Bulletin #110 – Pre-Exercise Supplementation

If your training, whether it is aerobic, strength, or both, is destined for super-intensity, then you’ve got to pay attention to your pre-exercise nutrition, particularly supplements. In case you don’t know it, there is an exact science to pre-exercise supplementation, and I’m going to cover it for you here and specify what you need to take and when you need to take. If you are going to get serious about your training, you must get serious about pre-exercise supplementation .Three to Four Hours Prior to Train-ing A carbohydrate-rich meal eaten ap-proximately four hours prior to exercise significantly pumps up muscle and liver glycogen content for better intensity for workouts, according to research. You can increase the carbohydrate content of your meal by including Parrillo ProCarb For-mula, Parrillo Energy Bar, or one of our new Parrillo puddings as part of that meal .

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Incidentally, any interval greater than four hours just won’t cut it. In a University of North Carolina study, women who ate a moderately high carbohydrate, low fat meal three hours prior to aerobic exercise performed with more energy and less fa-tigue than a group who ate their meal six hours prior to exercise.(1)Exactly how much carbohydrate should you consume in this critical pre-exercise period? An Ohio State University study determined that eating 200 to 350 grams of carbohydrate improves performance substantially.(2)30 Minutes Prior to TrainingAlso, I recommend that you take Par-rillo Max Endurance Formula 30 minutes to an hour before training. This supple-ment contains the following endurance-enhancing nutrients: inosine; a nutrient that improves oxygen utilization for better stamina, possibly by forcing additional production of energy-producing ATP; l-phenylalanine, an essential amino acid that acts as a potent mental stimulant for improved concentration during workouts; d-phenylalanine, an amino acid that pro-motes a higher pain threshold; and ferulic acid (FRAC), a nutrient stimulates the en-docrine system to aid recovery and boost workout capacity.

This supplement also contains mag-nesium and potassium aspartates, which help filter waste products from the sys-tem, giving you extra stamina and extend-ing endurance .Immediately Prior to TrainingSupplementing with a dose of creatine monohydrate right before your work-out provides energy-giving benefits too. Among other effects, creatine increases levels of a high-energy compound called creatine phosphate, which also allows more rapid production of ATP. The more ATP that is available to muscle cells, the longer, harder, and more powerfully you can work out.By supplementing with Parrillo Creatine Monohydrate right before your workout, you can load it into your muscles at just the right time to maximizing muscular reserves and restocking ATP.To use creatine in your supplement program, there is a specific dosage pro-gram to follow. I recommend taking four 5-gram doses a day for five days. (Take one of these doses prior to your workout, as noted above.) This is known as the “loading phase.” From there, two to 5 grams once a day — about half a teaspoon — will keep your muscles saturated with enough extra creatine.

This period is called the “maintenance phase.”Another strategy is to combine Cap-Tri®, our medium chain triglyceride oil (MCT oil), with a carbohydrate supple-ment such as ProCarb. For background, CapTri® provides twice the energy of protein and carbohydrate (8.3 calories per gram versus 4 calories per gram for carbohydrates and protein) and is ab-sorbed into the bloodstream as rapidly as glucose or blood sugar, the cellular fuel made available from the breakdown of carbohydrates. Second, CapTri®, is preferentially used as fuel for energy, instead of being stored by the body. Medium chain fatty acid fragments can diffuse into the cell very quickly, where they are burned immedi-ately for energy — at the same time as glucose. The ability of MCTs to enter the cells in this manner has a glucose-spar-ing effect, meaning that glucose and its stored counterpart, muscle glycogen, last longer without being depleted. The longer glycogen reserves last, the more energy you have for activities and fat-burning exercise. So to boost your endurance during exercise, take CapTri® with a carbohydrate-based beverage (again, ProCarb is a good choice). A similar combo has been tested scientifically. At the University of Cape Town Medical School in South Africa, researchers mixed 86 grams of MCT oil (nearly 3 tablespoons) with two liters of10 percent glucose drink to see what effect it would have on the performance of six endurance-trained cyclists .

The cyclists were fed a drink consisting of glucose alone, glucose plus MCT oil, or MCT oil alone. In the laboratory, they pedaled at moderate intensity for about two hours and then completed a higher-intensity time trial. They performed this cycling bout on three separate occasions so that each cy-clist used each type of drink once. The cy-clists sipped the drink every ten minutes. Performance improved the most when the cyclists supplemented with the MCT/glu-cose mixture. The researchers did some further biochemical tests on the cyclists and confirmed that the combination spared glycogen while making fat more acces-sible for fuel.When you supplement with CapTri® by itself, start with 1/2 tablespoon at every meal. After a few days, increase to one tablespoon with each meal. During hard training, many athletes go as high as two to three tablespoons per meal - a level they have found to be beneficial.

References

1. Maffuci, D.M., et al. 2000. Towards optimizing the timing of the pre-exercise meal. International Journal of Sport Nutri-tion, and Exercise Metabolism 10: 103-113 .

2. Coggan, A.R., et al. 1992. Nutritional Manipulations before and during endur-ance exercise: effects on performance. Medicine and Science in Sports and Exer-cise 24: S331-335 .

3. Lambert, E.V., et al. Nutritional strat-egies for promoting fat utilization and delaying the onset of fatigue during pro-longed exercise. Journal of Sports Science 15: 315-324 .

Bulletin #90 – Doing Carbs Right: Controlling Insulin Release

These days you can’t pick up a magazine or look at the best seller list in the bookstore without seeing something about low carbohydrate diets. Low carbohydrate ketogenic diets have their primary applica-tion in facilitating fat loss. Such diets work to help you lose weight in part by reducing insulin levels. Insulin is a storage hormone and promotes the storage of carbohydrate as glycogen as well as promoting the use of carbohydrate as fuel. What many people don’t realize is that insulin also inhibits lipolysis, the release of stored fat from fat cells. Insulin shifts the body’s metabolism into a carbohydrate mode and shuts off fat burning. This all makes perfect sense if you think about it. The role of body fat is primarily to store energy for times when food is not available. When you eat, insulin is released in response to the carbohydrate content of the meal and acts to promote the utilization of that carbohydrate for energy. If carbohydrate is available as a fuel source your body will prefer to use it instead of fat, since it wants to save body fat as an insurance policy against starvation.If your only goal is fat loss, reduced carbohydrate diets do make some sense. We’ve used this strategy with our bodybuilders for years, hav-ing them progressively reduce starch intake before a contest to help get them ripped.

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During this time we have them increase their intake of CapTri® to make sure energy levels don’t suffer. CapTri® is a proprietary medium chain triglyceride (MCT) formula that is used immediately for energy-more rapidly than glucose in fact. CapTri® has minimal effects on insulin so it is an ideal energy source during reduced carb dieting. Using CapTri® in place of some portion of your normal starchy carbohydrate intake will reduce insulin levels and shift your metabolism into a fat-burning mode. CapTri® itself is used immediately for en-ergy and is not stored as body fat. CapTri® is a dieter’s dreams come true .While reducing carbohydrate intake works well to assist fat loss, it’s not the best diet for all situations. Athletes, particularly endurance athletes and team sports players, need the quick energy that carbohydrates provide.

Bodybuilders are equally as inter-ested in gaining muscle as they are in losing fat, and carbs provide energy for muscular growth. Bodybuilders also enjoy having full, hard muscles, and that comes, in part, from glycogen stored in the muscle cells . Athletes, whether they are aware of it or not, want to store glycogen in their muscles in order to look and perform their best, and glycogen storage requires eating carbohydrates. Is there some way we can derive the benefit of carbohydrates and still get leaner?Yes, there is . You can include a sig-nificant amount of carbo-hydrate in your diet and still lose fat-if you do it right. The strategy behind a reduced carbohydrate diet is not to avoid carbohydrates per se-but rather to reduce insulin levels. Carbs don’t make you fat-it’s the insulin release fol-lowing carbohydrate ingestion that is the culprit. This biochemical sequence prevents you from losing the stored body fat you already have. At Parrillo Performance we have developed a dietary plan that allows you to eat carbohydrates while minimizing the insulin response.

This gives you the best of both worlds: the benefits of carbohydrate in providing energy for growth and athletic performance-plus the benefit of reducing insulin levels.Understanding how the Par-rillo diet works is really not too complicated once you understand some basics about metabolism. Both protein and carbohydrate stimulate insulin release from the pancreas, but carbs are a significantly more potent stimulus than protein is . And not all carbs are created equal. Gram for gram, some carbs elicit a much stronger insulin response than others. We divide carbs into four cat-egories . First are simple sugars and refined carbohydrates, then there are starches and fiber. You want to avoid simple sugars and refined carbs since these are the most potent insulin se-cretors. Simple sugars are found in desserts and sweets and are major in-gredients in soft drinks. Last month I stated that the average American consumes a staggering 153 pounds of refined sugar per year. Most of this is concealed in processed foods, convenience foods, soft drinks, and sweets. Many cereals also are very high in sugar. When you’re reading the labels to check for sugar content remember that high-fructose corn syrup is a sweetener loaded with the sugar fructose, which is even more potent in promoting fat storage than table sugar.You might be surprised to learn that fruit, fruit juice and milk are high in sugar. Almost all of the calories in fruit and juice derive from natural fruit sugars.

Although milk is an outstanding protein source, it contains more calories from sugar than from protein. Fruit and dairy products have many healthy attributes but are relatively high in sugars and the fact that these sugars occur naturally doesn’t make it any better for you. So for people seeking to achieve ultimate leanness, I strongly suggest they avoid fruit, juice, and dairy products. Refined carbohydrates are made from grains milled to produce flour. The problem is that in the manufacturing process the fiber is removed from the grain, leaving only starch. Then the grain is pulverized to produce a fine powder. This greatly increases the surface area of the starch, thus increasing it’s rate of digestion and absorption. Refined carbs are absorbed as quickly as sugar, and thus have essentially the same effect on insulin levels as eating sugar does. Anything made from flour is a refined carbohydrate. This includes bread and pasta and baked goods like cakes and muffins. Most snack foods (including pretzels, commonly misconstrued as being a healthy snack) are made from refined car-bohydrates. Most cereals are made from a mixture of refined carbohydrate and sugar. If you want to reduce insulin levels and still be able to eat carbohydrates, start by eliminating the carbs that are the most potent insulin releasers . This includes simple sug-ars, sweets, refined carbs, fruit, milk, bread, pasta, and most cereals . Eliminating these foods from your diet will make you notice-ably leaner.

The best carbohydrate choices are unrefined, complex carbohydrates and fibrous vegetables. Good starchy carbs are oatmeal, whole grain rice, potatoes, sweet potatoes, corn, peas, lentils, beans, legumes, and any whole grain. While primarily starch, these foods are natural and unrefined and are high in fiber. The presence of fiber in the stomach reduces the rate of digestion and absorption of the carbohydrate, thus reduc-ing its insulin response. Good examples of fibrous carbohydrates include salads and other greens, broccoli, cauliflower, Brussels sprouts, green beans, onions and peppers. The Parrillo Performance Nutri-tion Manual™ contains a food composition table giving an extensive list of this type of category, and the best food choices, along with the nutritional breakdown of the indi-vidual food.If you want to do carbs right the first step is to avoid the carbohydrate sources which elicit a big insulin release and instead select foods that are digested more slowly. Two important concepts are meal structur-ing and meal patterning . Meal structuring is simply the proper construction of each individual meal. Each meal should contain a protein source, an unrefined complex car-bohydrate to provide starch, and a fibrous vegetable. (The exception to this is the pre-contest diet in which starch is eliminated from some meals, particularly those late in the day.)

The presence of protein in the stomach slows the rate of digestion and ab-sorption of carbohydrate, as does fiber. The exact ratio of protein to carbohydrates varies among individuals depending on what are the specific training and dietary goals. If you want to do carbs right the first step is to avoid the carbo-hydrate sources which elicit a big insulin release and instead select foods that are digested more slowly.As a good rule of thumb, during a weight gain period eat one to two grams of protein per pound of body weight each day and supply the rest of your calories from unrefined, complex starchy carbs and fibrous vegetables. Minimize fat intake. For weight loss, most people get good results by increas-ing their protein intake and simultaneously decreasing carbohydrate intake. The ratio of protein to carbs will change depending on whether your goal is weight gain or fat loss. This will vary from individual to individual. People who store fat easily do better with less carbs and more protein. People who are naturally thin and want to get bigger achieve better results by consuming more carbohy-drates. Some people are more sensitive in their metabolic response to carbohydrates than others . Thin people generally tolerate more carbs without getting fat.

The Parrillo Performance Nutrition Manual goes into extensive detail in teaching about food com-bining and meal structuring and does a more complete job than I have room for here.Meal patterning refers to how many times you eat per day. Eating small, frequent meals gives better results than eating a few larger ones. That’s because a large meal supplies more calories and generates a larger insulin response. By eating small, frequent meals you never get that big insulin release. Also, you have a more uniform energy level. I recommend eating six small meals per day spaced out evenly every two-and-a-half to three hours. Try to get at least a minimum of five meals. If you have trouble eating regular food meals that frequently, make two meals a day supplement meals. Our 50-50 Plus drink mix and the Parrillo Nutrition Bars are ideal for this purpose. Implementing these dietary concepts will allow you to eat carbohydrates while also moderating insulin levels. You will feel better, have more energy and get leaner and stronger. Eliminating sweets and refined carbs makes most people feel more energetic, not less . For more detailed information re-fer to the Parrillo Performance Nutrition Manual™.

Bulletin #86 – Carbohydrates: The Bodybuilders Best Friend or Worst Enemy?

Your body needs fuel to power its activities. During low level activity, like casual walking, fat serves as a pri-mary fuel source. As exercise intensity increases your body comes to rely more heavily on carbohydrates for its source of energy. During prolonged endurance activities such as aerobics (and especially after glycogen reserves become depleted), amino acids can contribute significantly to the fuel mix, accounting for as much as ten percent of oxidized substrate. Since most of us exercise intensely, we are de-pendent on carbohydrates for optimal performance. This is true for both body-builders and endurance athletes. Of all the ergogenic (performance enhancing) substances available, evidence suggests that carbohydrates and water work best for powering through a workout. Without these critical nutrients the body cannot generate power and perform work at the optimal level.

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When endurance athletes “bonk” or “hit the wall” glycogen stores are depleted and blood sugar levels start to drop . This causes a dramatic reduction in muscular power output and causes fa-tigue of the central nervous system. The human body can store roughly 400 grams of glycogen, which is the storage form of carbohydrates. This amounts to about 1,600 calories and is not enough energy to last most of us even one day. Since we can’t store very much, it is critical to maintain an adequate supply of carbohydrates. The optimal carbohydrate intake varies from person to person, de-pending on athletic goals, body size and training pattern. Endurance athletes burn the most fuel and thus have the highest carbohydrate requirements. Bodybuilders who follow our Parrillo prescription of high intensity aerobics and weight training should consume a diet fairly high in carbo-hydrates. During the growth season, while the emphasis is on gaining lean muscle, a diet relatively higher in carbohydrates will help support weight gain. During pre-contest dieting, when the goal is fat loss, a reduction in carbohydrates works bet-ter. Carbohydrates are almost exclusively derived from plant sources.

Meat is a very poor source of carbohydrates. We divide carbohydrates into several categories. The first two are simple sugars and refined carbohydrates. Simple sugars include sugar and honey as well as fruit and fruit juice. Fruit is sweet because it contains the sugars glucose and fructose. It is advisable to avoid simple sugars and refined carbo-hydrates because they readily promote fat storage. To some extent they are converted into fat, but more importantly they cause a big insulin release from the pancreas and this blocks the use of fat as fuel. If you don’t burn any fat as fuel then it slowly accumulates. Fructose is found primarily in fruit but also in artificial sweeteners like high fructose corn syrup – which is especially bad since it is preferentially converted to fat in the liver. Examples of refined carbohydrates include bread, pasta and anything made with flour. That would include muffins and cookies, cake, crackers, pretzels and so on. Chips, even the low fat kind, will fall into this cat-egory since their carbohydrates are refined. During refining the grain which supplies the carbohydrate is pulverized and the fiber is removed. The carbohydrates are ground into a fine powder and this increases its surface area-to-mass ratio .

These factors, taken together, result in certain carbohydrates being di-gested, entering the bloodstream very rap-idly and triggering a powerful release of insulin. Refined carbohydrates behave in the body much like simple sugars and we recommend that athletes trying to get in shape avoid all simple sugars and refined carbohydrates, including sugar, fruit, fruit juice, bread and pasta. Milk is not a good bodybuilding food since it is rich in the simple sugar lactose. A glass of milk ac-tually contains more sugar than protein, something a lot of people don’t real-ize. Starches and fibrous vegetables are “good” carbohydrate sources and we en-courage our athletes to eat these . Starch is a long chain of glucose. Glucose is sugar released into the bloodstream and a primary fuel for muscles. Glucose is the storage form of carbohydrates in plants. Glycogen is very similar to starch and is the storage form of carbohydrates in animals. The difference between starch and glycogen has to do with the branch-ing pattern and starch is a good energy source that is digested slowly compared to refined carbohydrates. This results in a more favorable insulin profile for starch.

Starch is the best food source of carbohydrate for athletes. Good examples of starchy carbs include oatmeal, corn, peas, rice, beans, potatoes, sweet potatoes, lentils, legumes, and whole grains. Fibrous vegetables don’t supply many calories but are the prime sources of fiber, a critical nutrient for bodybuild-ers. Fiber slows the rate of release of glucose into the bloodstream thus helping to moderate insulin levels. Good fibrous vegetables are lettuce, spinach, aspara-gus, broccoli, cauliflower, brussel sprouts, beans (not canned), lentils, peas, turnip greens, squash, zucchini, okra, oatmeal, oat bran, All-Bran cereal or Fiber-One cereal (check to make sure these have no sugar), cabbage, celery, peppers, sweet potatoes, eggplant, cucumbers, onions and whole grain brown rice. Generally any other vegetable is acceptable. I would stay away from avocados, olives and nuts, as they are high in fat. It is important to combine foods properly when you prepare a meal. We call this “meal structuring.” Each meal should contain a protein source, a starchy carbohydrate and a fibrous vegetable.

By combining protein and fiber with your starch, and by avoiding simple sugars and refined carbohydrate, the rate of release of glucose into the bloodstream is greatly reduced. This helps keep insulin levels low which permits the continued use of fat as fuel. This style of eating encourages ingested nutrients to be stored as muscle or glycogen rather than compartmentalized in fat storage. How many carbohydrates should you eat in a day? This varies from person to person, so I can’t give you some magic number, but I can teach you how to figure it out for yourself. The first thing to con-sider is your daily caloric requirement. If you don’t already know what that is, start weighing your food and use a calorie chart to calculate how many calories you are consuming each day. The Parrillo Per-formance Nutrition Manual comes with a food scale and diet trac sheets along with detailed instructions.

Next, construct your diet so that fat is limited to 5-10% of calo-ries consumed and eat one to two grams of clean (low fat) protein per pound of body weight each day. If you’re lean and are try-ing to gain weight add more carbohydrates. If you are trying to strip off fat try eating two grams of protein per pound of body weight each day and cut back on your carb intake. Establish your daily intake of calories from fat and protein and derive the rest from quality carbohydrates. Include starchy and fibrous carbs at each meal, avoiding the other carb sources.Did you ever wonder how carbo-hydrates are metabolized in the body? The starch is broken down into glucose units inside the small intestine and absorbed into the bloodstream. From there it is carried to the liver by the portal vein. Much of it is retained in the liver where it is converted into glycogen. Once liver glycogen stores are filled to capacity the remainder of the glucose load is released into the gen-eral circulation where it is taken up by the muscles, brain, or other organs and used as fuel. As long as blood glucose levels are normal, glucose is (generally) used pref-erentially as fuel over fat or amino acids. Muscle has the ability to store glycogen, so whatever glucose is taken up by muscle - but is not needed immediately for fuel - is retained as glycogen .

Under normal conditions not much glucose is converted into fat, although this can happen during prolonged periods of over-eating. Glucose can be used as fuel or stored as glycogen by liver and muscle. Several hours after the meal, when blood glucose levels start to drop, liver glycogen is broken down and the stored glucose is released into the bloodstream. You can maintain fairly uni-form blood glucose levels without having to eat constantly .Parrillo’s Pro-Carb Powder™ and 50-50 Plus™ are both excellent sources of Carbohydrates: The Bodybuilders Best Friend or Worst Enemy?slow-release carbohydrates and ideal for both improving exercise performance and providing post-workout glycogen replace-ment. In terms of convenience it’s impos-sible to beat Parrillo Bars. Keep some in your gym bag and have one when you finish your workout to start replenishing glycogen right away. Try and get a handle on the different types of carbohydrates. Eliminate the refined carbs and those that contain sugar . Manipulate your starch and fiber intake to achieve your desired results. Keep tabs on your carbs and how much you ingest. You will be well on your way to achieving the physical goals to which you aspire .

References

1. Flatt JP. Dietary fat, carbohydrate bal-ance, and weight maintenance: effects of exer-cise. Am. J. Clin. Nutr. 45: 296-306, 1987.

2. Flatt JP. Use and storage of carbohydrate and fat. Am. J. Clin. Nutr. 61: 952s-959s, 1995.

3. Acheson KJ, Flatt JP, and Jequier E. Gly-cogen synthesis versus lipogenesis after a 500 gram carbohydrate meal in man. Metabolism 31: 1234-1240, 1982 .

4. Liebman M and Wilkinson JG. Carbohydrate metabolism and exercise. Chapter 2 from Nutri-tion in Exercise and Sport, edited by Wolinsky I and Hickson JF, CRC Press, Boca Raton, 1994.

5. Miller GD. Carbohydrates in ultra-endurance exercise and athletic performance. Chapter 3 from Nutrition in Exercise and Sport, edited by Wolinsky I and Hickson JF, CRC Press, Boca Raton, 1994.

6. Hargreaves M. Skeletal muscle carbohydrate metabolism during exercise. Chapter 2 fro-mExercise Metabolism, edited by Hargreaves M, Human Kinetics Publishers, Champaign, IL, 1995.

7. Coggan AR and Williams BD. Metabolic adaptations to endurance training: substrate metabolism during exercise. Chapter 6 from Exercise Metabolism, edited by Har-greaves M, Human Kinetics Publishers, Champaign, IL, 1995.

Bulletin #58 – Carbohydrates — The Optimal Fuel For Success, Part II

In the last article we began ourdiscussion of carbohydrates as the pre-ferred fuel for athletic performance. It iswell known that the ability to sustain mod-erate to heavy exercise for prolonged pe-riods of time is related to initial muscleglycogen concentration (1). The moreglycogen you have stored in yourmuscles, the longer you can exercise at agiven work load. One experiment showedthat when muscle glycogen levels were0.63 grams of glycogen per 100 gramsof muscle, a standard exercise load couldbe maintained for 57 minutes before fa-tigue. When glycogen levels were in-creased to 1.75 grams per 100 grams ofmuscle, the same exercise could be per-formed for 114 minutes. And if the initialglycogen level was 3.31 grams per100 grams of muscle the exercisecould be continued for 167 minutes(1,2). The close correlation betweenmuscle glycogen levels and time toexhaustion is a good reason to fol-low a high carbohydrate diet. It hasbeen suggested that glucose andfatty acids cannot cross the cellmembrane (that is, enter the cell)fast enough to provide adequate fuelfor intense exercise (1). This is whymuscle glycogen (glycogen alreadystored inside muscle cells) is themost important fuel for exercise.Now let’s talk about somespecific dietary strategies to maxi-mize endurance performance. It isvery important to fill glycogenstores completely before participating inan exhaustive endurance event.  

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Endur-ance athletes who train on successive daysare likely to require 65-75% of their calo-ries from carbohydrates to optimize per-formance (1). It may be that feelings oftiredness which are attributed to overtrain-ing are in fact due to low glycogen stores(1). Some cases of “overtraining” mayreally just be under-nutrition. Foods richin complex carbohydrates are preferableto refined sugars because they are morenutrient dense and result in lower bloodglucose and insulin levels. This makes itmore likely that the carbohydrate will bestored as glycogen rather than being con-verted to fat. It is recommended that thelast meal consumed before an enduranceevent be relatively light and contain a mix-ture of easily digested complex carbohy-drate and protein (1). This meal shouldbe eaten about two to three hours prior toexercise to allow time for the stomach toempty. Improvements in exercise perfor-mance from pre-exercise carbohydrateingestion is probably due to a delay in thenormal decline of blood glucose duringexercise (1). Most likely, this works bysupplementing hepatic (liver) glycogenreserves. A recent study has shown thatingestion of one to two grams of carbo-hydrate per kilogram of body weight onehour before exercise can improve perfor-mance (1). In this experiment the carbo-hydrate was given in liquid form, whichis what we would generally recommendif you’re going to eat something withinan hour of exercise. This allows for morerapid digestion and absorption than is pos-sible with solid food.

Pro-Carb Powder™(original Vanilla or the new Chocolate fla-vor) is ideal for this, supplying 22 gramsof medium-chain carbohydrate(maltodextrin) along with four grams ofprotein per scoop. That means a 180pound athlete would need about fourscoops taken 30-60 minutes before com-peting.Consuming carbohydrates duringexercise can also improve performance.This works by helping to maintain bloodglucose levels and preventing hypoglyce-mia, rather than by sparing muscle gly-cogen (1). Keep in mind I’m talking aboutmaximizing exercise performance here,not fat burning. If you’re doing aerobicssimply to burn fat then you don’t wantto eat anything during exercise be-cause this will decrease the utiliza-tion of body fat as fuel. Competitiveendurance athletes may however im-prove performance by consuming acarbohydrate drink during exercise.This will help replace fluids as wellas maintain blood glucose.

The rateof gastric (stomach) emptying is keyhere, as this ultimately controls theavailability of the ingested carbohy-drate. The stomach empties faster thefuller it is, so it is advised to keep thestomach volume relatively high bytaking frequent small drinks.Maltodextrin theoretically should exitthe stomach faster than glucose so-lutions due to its lower osmolality (theconcentration of particles in a solution).A rate of about 45 grams of supplementalcarbohydrate per hour seems adequate tomaintain blood glucose levels during mod-erate exercise (1). This would be onescoop of Pro-Carb Powder™ every 30minutes.Whatever you do, stay awayfrom fructose as an exercise fuel. Fruc-tose is the sugar found naturally in fruit and, ironically, in most sports bars (theParrillo Bar uses rice dextrin, not fruc-tose). Some people recommend fructosefor athletes because it has a low glycemicindex and results in a low insulin response.This line of reasoning however fails toconsider the big picture of fructose me-tabolism. Fructose is a bad choice for ath-letes for two reasons. First, a significantproportion of it is converted to fat by theliver. This is probably the reason it has alow glycemic index and a low insulin re-sponse. Second, it does not work well forrestoring muscle glycogen. Fructose ismetabolized by the liver, not by muscle.

Trials with fructose supplementation dur-ing exercise have failed to demonstrate animprovement in performance (1) and us-ing fructose as a carbohydrate source toreplenish muscle glycogen stores follow-ing exercise does not work as well as glu-cose or glucose polymers (1,2).Restoration of muscle and liverglycogen reserves after exercise is criti-cal for recovery and subsequent exerciseperformance (1). I feel it is also very im-portant in order to derive the maximaltraining effect from exercise, so that youcan go out and have improved perfor-mance next time. Now we will discussthe type, timing, and amount of carbohy-drate needed to maximize recovery of gly-cogen stores after exercise.Research shows that glycogenlevels can be restored within 24 hours fol-lowing exhaustive exercise if 600 gramsof carbohydrate are consumed (1). Thismakes good theoretical sense, becausemost people can store around 400 gramsof carbohydrate as glycogen (and maybetwice that much using carb loading tech-niques). So 600 grams provides enoughto replenish glycogen stores plus a littleleft over to use as fuel during your recov-ery day. (It is assumed that you will notbe exercising during this 24 hour period.)The rate of glycogen synthesis is mostrapid immediately following exercise.

This is due to several factors, includingincreased activity of the enzyme thatmanufactures glycogen, increased perme-ability of the muscle cell membrane to glu-cose, and increased sensitivity of muscleto insulin following exercise (1). Youshould try to consume one to one-and-a-half  grams of carbohydrate per kilogramof body weight every two hours for thefirst six hours after exhaustive exerciseand a total of 600 grams during the first24 hours.The type of carbohydrate usedalso affects the degree of glycogen reple-tion. This effect is most likely due to theglycemic and insulinemic responses ofvarious carbohydrates. Fructose causesa much lower blood sugar level and insu-lin level than glucose-based carbohydrates.It is well known that fructose is not nearlyas effective as glucose at restoring muscleglycogen (1,2). This is probably becausefructose metabolism is essentially confinedto the liver. Several studies have comparedsimple sugars versus complex carbohy-drates, with various results. Some stud-ies have found no difference, and somehave suggested that simple sugars resultin better glycogen recovery during the first24 hours.

One study found that complexcarbohydrates resulted in higher rates ofglycogen synthesis after 48 hours (1,2).Apparently complex carbs work betterover the long term and higher levels ofglycogen can ultimately be achieved us-ing complex carbs. My recommendationis to avoid sugar but to use a relativelyshort chain glucose polymer such asfound in Pro-Carb Powder™ or theParrillo Bar for the first six hours afterexercise and then rely on complex carbsfor the remainder of glycogen repletion.This should result in optimal glycogenrecovery. Simple sugars are more easilyconverted to fat than complex carbohy-drates, and this may be the reason thathigher glycogen levels are seen after 48hours with complex carbs. The complexcarbs are more prone to be stored as gly-cogen while simple sugars more readilyspill over into fat stores. The best carbchoices for glycogen repletion are com-plex starches such as rice, potatoes, sweetpotatoes, beans, oatmeal, and so on. Con-trary to what some proponents of the highfat diet say, current research proves thatcomplex carbohydrates have very little ten-dency to be converted to body fat (3,4,5).Several studies have directlycompared the effects of carbs versus faton endurance. One compared a high carb- low fat diet (83% carbs, 3% fat) to ahigh fat – low carb diet (94% fat – 4%carbs).

They found that the group con-suming high carbs burned more carbo-hydrate during exercise and had an en-durance time of 210 minutes comparedto 88 minutes for the high fat group (2).A high carbohydrate diet results in greatermuscle and liver glycogen stores plushelps maintain blood glucose levels longer,resulting in greater endurance. Hard train-ing athletes need extra carbohydrate tosupport their exercise activity. When agroup of athletes was fed a diet contain-ing 40% carbohydrate, their muscle gly-cogen levels steadily declined over a fewdays of training. When they wereswitched to another diet containing thesame number of calories but 70% carbs,their glycogen stores were maintained (2).This is very important. It means that notonly do athletes need extra calories to fueltheir exercise activity, but it also matterswhere the calories come from. A high fatdiet cannot maintain glycogen stores evenif it is adequate in calories. This is be-cause fat cannot be converted to glycogen. Also keep in mind that athletes needmore protein than sedentary people. Thishas been proven in many studies usingnitrogen balance techniques.We recommend a diet providingone to one-and-a-half grams of protein perpound of body weight each day with therest of the calories provided by complexcarbohydrates.

Try to limit fat to 5-10%of calories. Use high quality, low fat pro-teins such as chicken breast, turkey breast,egg whites, and fish. Good starchy carbsare things like potatoes, rice, beans, andoatmeal. At each meal you should alsoinclude a fibrous carb, such as broccoli,asparagus, salad greens, or other veg-etable. Each meal should be balanced,containing one complete protein source,a starch, and a fibrous vegetable. Try todivide your daily grams of protein and yourtotal calories evenly among six smallmeals. The Parrillo Performance NutritionManual contains exact instructions onwhich foods to eat, which foods to avoid,and how to structure your diet. It alsocontains a detailed food composition guideand comes with a food scale, so you candetermine how many calories and howmany grams of protein, carbs, and fatyou’re consuming. It contains precise di-rections on how to modify your diet tooptimize gaining lean mass or losing bodyfat.Regarding supplementation,Parrillo Performance Hi-Protein Powder™is a high efficiency protein mixture pro-viding a high level of glutamine, branchedchain aminos, and essential aminos. Thisis an excellent way to get your proteinintake up where it needs to be. It’s nowavailable in chocolate, which is delicious.Endurance athletes and bodybuilders try-ing to gain weight will do well with Pro-Carb Powder™, a maltodextrin-based car-bohydrate supplement. This is an idealsupplement for glycogen repletion andcarb loading.

We have had great successusing it alone or in combination withCapTri® before and during enduranceevents.Another product that we’ve justintroduced called 50/50 Plus™ fits thisneed for additional carbs and proteinnicely. With 20 grams of protein and 17grams of complex carbohydrate in eachtwo scoop serving, 50/50 Plus™ providesyour body with the protein necessary tostave off muscle catabolism for energyas well the extra carbs to supply energywhen you need it and help replenish gly-cogen stores when you’re finished withyour activity. 50/50 Plus™ comes in fourdelicious flavors — Vanilla, Chocolate,Orange Cream, and Milk — and can bemixed with water or stirred into your foodto boost your nutrient levels.Endurance athletes should also considerLiver-Amino Formula™. This supplementis the ultimate source of heme iron, whichis a superior iron source for building bloodcells. Creatine is another supplement thatcan help extend your energy base. And allserious athletes should be using EssentialVitamin Formula™ and Mineral-Electro-lyte Formula™.Even if you’re a bodybuilder andnot an endurance athlete, vigorous aero-bic exercise will help you get bigger andleaner. Aerobics helps build capillary den-sity in muscle tissue, allowing for betternutrient delivery and more growth. Aero-bic conditioning also trains your musclesto rely more on fat as a fuel source butincreasing mitochondria and the level offat burning enzymes (6,7). This helps youCarbohydrates—The Optimal Fuel For Success, Part IIget leaner plus spares muscle glycogenfor a better pump. Until next time, goodtraining.

References

1. Liebman M and Wilkinson JG. Carbo-hydrate metabolism and exercise. Chap-ter 2 from Nutrition in Exercise and Sport,edited by Wolinsky I and Hickson JF, CRCPress, Boca Raton, 1994.

2. Miller GD. Carbohydrates in ultra-en-durance exercise and athletic perfor-mance. Chapter 3 from Nutrition in Exer-cise and Sport, edited by Wolinsky I andHickson JF, CRC Press, Boca Raton,1994.

3. Flatt JP. Dietary fat, carbohydrate bal-ance, and weight maintenance: effects ofexercise. Am. J. Clin. Nutr. 45: 296-306,1987.

4. Flatt JP. Use and storage of carbohy-drate and fat. Am. J. Clin. Nutr. 61: 952s-959s, 1995.

5. Acheson KJ, Flatt JP, and Jequier E.Glycogen synthesis versus lipogenesisafter a 500 gram carbohydrate meal inman. Metabolism 31: 1234-1240, 1982.

6. Hargreaves M. Skeletal muscle carbo-hydrate metabolism during exercise.Chapter 2 from Exercise Metabolism, ed-ited by Hargreaves M, Human KineticsPublishers, Champaign, IL, 1995.

7. Coggan AR and Williams BD. Meta-bolic adaptations to endurance training:substrate metabolism during exercise.Chapter 6 from Exercise Metabolism, ed-ited by Hargreaves M, Human KineticsPublishers, Champaign, IL, 1995.

Bulletin #57 – Carbohydrates — The Optimal Fuel For Success

Recently we talked about the ben-efits of a high carbohydrate diet as com-pared to the high fat diet in terms of get-ting lean. Not all calories are cre-ated equal. Dietary fat is preferen-tially stored as body fat, whereascarbohydrates do not significantlycontribute to fat stores (1,2,3). Mostof your body fat is derived from thefat you eat and very little comesfrom conversion of protein or car-bohydrate into fat (1,2,3). So itmakes sense that if you want to re-duce body fat the first place to startis to eat less fat. Proponents of thehigh fat diet say that carbohydratescause insulin release which in turnstimulates fat storage. On the Parrillodiet we teach you how to select car-bohydrate sources and structureyour meals so that carbohydrates arereleased into the bloodstream veryslowly, so this isn’t a problem. Tolook at the big picture, if you con-sume too many calories from anysource for a prolonged period oftime some of these calories will end up asbody fat. Conversely, if you operate in acalorie deficit for a prolonged period oftime you will lose some fat. However, theresults you will get in either of these situ-ations are different depending on if yousupply the bulk of those calories in theform of fat or carbohydrate. We havefound that if you eat a diet higher in carbsand low in fat you will end up being leanerand more muscular whether you are us-ing the diet to gain weight or lose weight.

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This month I want to talk aboutthe other half of the story, that carbohy-drates are a superior fuel for exercise per-formance compared to fat. Not only willcarbs make you leaner, they’ll also giveyou more energy, strength, and endurance.We’ll start with a review of energy sub-strate utilization during exercise, and thentalk about dietary strategies to maximizeyour exercise performance. This discus-sion will apply equally well to bodybuild-ers and endurance athletes.Adenosine triphosphate (ATP) is the mol-ecule that directly provides energy for yourmuscles. Before any foods can be usedto fuel exercise, the energy they containmust be converted into ATP. When ATPis broken down it forms adenosine diphos-phate (ADP) and free phosphate. To dothis a phosphate bond is broken. Whenthis happens energy is released and it isthis energy which powers muscular con-tractions.

You know that when you burnwood in your fireplace heat is released.Heat is a form of energy. When food isburned inside your body the energy whichis released is used to manufacture ATP.The ATP is then broken down releasingthat energy which it captured from thefood, and this energy is the fuel your bodyuses at the cellular level to do its work,including muscular contractions.The amount of ATP stored insideyour cells is very small. Muscle cells con-tain enough ATP to power a maximal con-traction for about two to four seconds(4). So the ATP has to be continu-ally replenished as it is used. Thereare three energy systems in placefor making new ATP so you cancontinue to exercise beyond fourseconds. These are the phosphagensystem, the lactic acid system, andthe aerobic system. The phosph-agen system is comprised of the“high energy phosphate com-pounds,” which include ATP andcreatine phosphate (CP). This isby far the fastest energy systemand can provide for rapid burstsof high intensity exercise such asweight lifting, sprinting, football,and some track and field events.Muscle cells contain from three tofive times more CP than ATP, andthe phosphagen system can sus-tain maximal exercise for about sixto eight seconds. After that, the CPis also used up and we have to ac-tivate another energy system. You can seewhy creatine is such an effective andpopular sports supplement. It helps to pro-vide more immediate energy allowing forhigher intensity exercise.

This is why cre-atine increases strength in weight lifters.As a nice “side effect” it also attracts waterinto the cell, making the muscles fullerand harder.The next energy system is the lactic acidpathway. This can provide maximal en-ergy for periods lasting up to one-and-a-half or two minutes. This pathway con-sists of the anaerobic conversion of glu-cose into lactic acid (anaerobic means“without oxygen”). This is actually a rela-tively long and complicated process in-volving several steps, and the overall path-way is called “glycolysis.” The end resultis that one glucose molecule is brokendown to form two lactic acid molecules, releasing energy in the process. This en-ergy is used to form ATP. Where doesthis glucose come from? By far the mostimportant source of glucose for this pro-cess is stored muscle glycogen (4,5).Let’s think about that for a minute. Howlong do most of your sets last in the gym?I’m not talking about the rest period, butthe amount of time you’re actually liftingweight with the muscle under tension.Probably anywhere from 30-60 seconds,generally.

This is definitely longer than thephosphagen system can hold out withoutbeing replenished from some other energysource. Without calling in reinforcements,the phosphagen system by itself couldonly get you through the first rep or two.So what this means is that for very in-tense (maximal or near maximal) exerciselasting about a minute or so, such asweight lifting, the lactic acid system is theprimary energy-producing pathway atwork (4,5,6). And the primary fuel sub-strate for the lactic acid system is storedmuscle glycogen (4,5,6). When you do aset in the gym most of the energy comesfrom stored muscle glycogen. So muscleglycogen is the most important fuel sourcefor weight lifters, sprinters, football play-ers, and other athletes performing shortbursts of maximal exercise. A high car-bohydrate diet is best for athletes becauseit helps maintain a high level of stored gly-cogen in muscle.The problem with fat as an en-ergy source for resistance exercise is thatfat cannot be converted into glucose orglycogen, at least in humans. So a highfat diet cannot maintain muscle glycogenand therefore cannot support as high alevel of exercise performance. You mightwonder how people on extremely lowcarb diets can manage to lift weights atall.

While fat cannot be converted into glu-cose, amino acids from protein break-down can. So even if you don’t eat anycarbs at all you can still get a little muscleglycogen from breakdown of protein andconversion of amino acids into glucose.Also, the high fat diet results in the pro-duction of ketones which can be used bymuscles as fuel for weight lifting. I sus-pect that most people who follow the highfat diets have extremely low muscle gly-cogen levels and in fact are able to per-form some degree of resistance trainingusing ketones as fuel. We have seen thatwhen CapTri is used as an energy supple-ment during low carb “cutting” diets thisgreatly improves the ability to continue lift-ing. And we know that CapTri works bybeing converted into ketones by the liver.So I suspect the same process is goingon with the high fat diets, except that itdoesn’t work nearly as well with conven-tional fats as it does with CapTri becauseCapTri is converted into ketones muchmore rapidly and completely than are con-ventional fats. On the Parrillo Programeven when we use CapTri in this way,the bodybuilder is still eating some carbs,just not as much as usual. So he still has asignificant store of muscle glycogen.

Theproblem with the high fat diet is not onlythat you have virtually no muscle glyco-gen, but also that the ketones which areavailable are not stored to any appreciableextent in muscle cells. So on low carbdiets you have no muscle glycogen, mean-ing that you’ve knocked out the primaryenergy pathway used in weight lifting-typeexercise. You do have ketones, but thesecan’t be stored inside the muscle. You haveless strength, less endurance, and sinceglycogen stores are depleted your musclesare flat and you have no pump. Not a verygood way to go. There can be no doubtthat carbohydrates are a much better fuelsource for bodybuilders and enduranceathletes than fat, and this is backed up bybiochemistry, by the scientific literature,and by our own testing here at ParrilloPerformance.The third energy pathway is theaerobic system. This system can provideenergy continuously for hours, but at alower level of intensity compared to theother pathways. This pathway can useboth carbohydrate and fat, and in fact isthe only energy system that can use fatas a fuel substrate. As explained above,very brief and intense exercise such asweight lifting and sprinting is fueled bythe lactic acid system (an anaerobic en-ergy-producing pathway) and very long,low intensity exercise such as walking isfueled by the aerobic system. Moderateintensity exercise such as jogging or bik-ing is fueled by a combination of both path-ways.

When the energy requirement de-manded by the exercise does not exceedthe ability of the aerobic system to supplyATP, then this is the primary energy sys-tem. A leisure walk is powered by theaerobic pathway, and you can sustain thislevel of activity for hours. If you pick upthe pace and start jogging at a comfort-able pace you can maintain for some time,this is still fueled by the aerobic pathway.If now you begin running fast, the aero-bic energy system can no longer supplyenough ATP to meet the energy require-ment of your muscles and the lactic acidsystem kicks in. You can keep up thispace for several minutes – longer than the2 minutes the lactic acid system could lastby itself because it is being supplementedby the aerobic system. Now if we moveup one more notch of intensity, such asweight lifting or an all-out sprint, the lac-tic acid system is operating at full boreand when muscle glycogen becomes de-pleted (among other factors) the exercisewill stop. The aerobic system simply can-not supply energy fast enough to keep upwith the demands of the muscle.Now let’s discuss how your bodyselects energy substrates during exercise.After we understand the patterns of en-ergy substrate utilization we can design effective dietary strategies to maximize ourresults. Glucose stored as glycogen inmuscle and liver, and fatty acids storedas triacylglycerols (fat molecules) in adi-pose depots, are both important fuelsources for exercise.

Factors which de-termine the balance between carbohydrateversus fat which is used as fuel includethe intensity of exercise, the duration ofexercise, the athlete’s level of condition-ing, and initial glycogen levels (4). Aminoacids can also be oxidized (burned) to pro-vide fuel, but normally contribute less than10% of the energy cost of exercise. Onthe Parrillo Program we do everything pos-sible to prevent the use of amino acids asfuel, because we want to maximize musclemass. So for people on our program thecontribution of amino acids to the fuel mixis even less than 10%.By far the most important thingyou can do to prevent use of protein asfuel is to make sure your muscle glyco-gen stores are always “topped off.” That’sanother serious draw-back of the verylow carb diets. Glycogen levels are so lowthe muscle protein is very vulnerable tobe broken down so that the aminoacids can be converted to glucoseand used as fuel. Adequate glyco-gen availability “spares” aminoacids, meaning that if your bodyhas carbs available to use as fuelit won’t need to use any protein.The next thing you can do is touse a scoop of Hi-Protein Powderright before your aerobics so thatif any amino acids are going to beused as fuel they will be derivedfrom the protein powder insteadof your muscles.

The Hi-Proteinis probably superior to regularfood for this purpose since it isdigested rapidly and the aminos arereleased into the bloodstreamfaster than from whole, solid pro-tein foods. I recommend doingyour aerobics first thing in themorning before breakfast, be-cause it’s at that time that bloodsugar levels are low and muscleglycogen is at the lowest level itwill be throughout the day. Thisresults in greater use of stored body fatas a fuel source during your aerobics sinceless carbohydrate energy is available. Thisdoes however put you at some risk forbreaking down muscle, so that’s why it’sa good idea to have a serving of Hi-Pro-tein Powder before your morning aero-bics. Keep in mind however that this con-dition of relative glycogen depletion I’mtalking about is a far cry from the near-zero levels resulting from low carb diets.Even first thing out of bed before break-fast, Parrillo bodybuilders have a lot ofglycogen on board. This just turns out tobe the time which it will be lowest duringthe day, so it’s the best time to burn fat.So, if we control things such that we usevery little or no protein as fuel, the energycost of our exercise is supplied by a mix-ture of carbohydrate and fat. The relativecontribution of carbohydrate and fat tothe substrate mix being oxidized can bedetermined by measuring the respiratoryquotient (RQ). This gets a little technicalhere, so I’ll be brief.

Carbohydrate mol-ecules such as glucose contain oxygen,so the carbon atoms in the carbohydratemolecule are already partially oxidized.However, the carbon atoms in a fatty acidmolecule are not partially oxidized. There-fore, when fat and carbohydrate areburned (oxidized) separately differentamounts of oxygen are consumed peramount of carbon dioxide produced. Soif we measure the amount of oxygen con-sumed and carbon dioxide produced byan athlete while he’s exercising, we can“back calculate” if he’s burning fat orcarbs as fuel. (I hope that wasn’t too pain-ful.) An RQ of 1.0 indicates that essen-tially pure carbs are being used as fuel,and an RQ of 0.7 indicates that fat is thefuel source. Intermediate values of RQdemonstrate that a mixture of carbohy-drate and fat is serving as the fuel supply.What experiments like this haveproven is that during very low intensityexercise (like walking) fat is the predomi-nant fuel source (4,5,6). During sleep orrest almost exclusively fat is used. So ifyou believe these guys who advocate lowintensity aerobics because it uses a higherpercentage of calories from fat, then justsitting around and watching TV shouldget you ripped. As the intensity of exer-cise increases, we see that more carbo-hydrate is used as fuel (4,5,6).

This pro-gression continues until exercise intensityreaches V02max, at which time carbohy-drate becomes the sole energy substrate(4). You will recall that V02max (vee-oh-two-max) represents the maximal rate ofoxygen consumption by an athlete. Thismeans that the aerobic energy system iscompletely maximized, and any furtherincrease in energy needs must be met bythe anaerobic (lactic acid) system. Sincefat cannot be used by the lactic acid sys-tem, the energy at this point can only besupplied by carbs. This all makes goodsense. We know that we can maintain lowintensity exercise for prolonged periodsof time (you could walk all day if youwanted to). That’s because this activityis powered by the aerobic energy path-way, which can use fat as a fuel source.Your body has many more calories storedas fat than it can store as glycogen, be-cause fat is a much more compact wayto store energy and because you have limited space to store glycogen. You can carryon this low level of activity indefinitelybecause you won’t run out of fat. But wecan only sustain maximal exercise for arelatively short time, because this relieson the lactic acid system which can onlyuse glucose as fuel (other factors con-tributing to muscle fatigue are also at playhere).

After the glucose (stored as glyco-gen) is used up the fat can’t burn fastenough to meet the demands of the exer-cise. At very high exercise intensity oxy-gen cannot be delivered to the muscle fastenough to allow the aerobic energy sys-tem to operate, so the muscle must relyon the anaerobic (lactic acid) system,which can only use carbohydrate. Thebottom line: fat cannot serve as the fuelsource for very high exercise intensity,because it cannot undergo anaerobic me-tabolism. Carbs are the only fuel that cansupport maximal exercise intensity.As you would expect, moderateintensity exercise uses a mixture of carbsand fat. As the duration of exercise pro-ceeds, muscle glycogen gradually be-comes depleted so oxidation of fat beginsto make a greater contribution. We alsosee greater uptake of glucose from thebloodstream. This is attributable to greatermuscle blood flow during exercise as wellas more efficient extraction of glucosefrom the blood by the muscle. After 20minutes of exercise muscle glycogenstores become partially depleted and theuse of muscle glycogen slows (4). Thisis accompanied by increased use of bloodglucose. The liver acts to help maintainblood glucose levels by breaking down itsglycogen stores and releasing glucoseunits into the bloodstream. After bothmuscle and liver glycogen stores are de-pleted, which takes about two or threehours of moderate intensity exercise(marathon running or long distance cy-cling for example), is when we really getin trouble.

At this point one of three thingsmust happen: the exercise must be stoppedor significantly reduced in intensity, bloodglucose must be maintained by carbohy-drate ingestion during exercise, or muscletissue will be destroyed to supply aminoacids as fuel.Carbohydrates—The Optimal Fuel For Success, Part IIt is well known that aerobictraining allows one to perform “more aero-bically” at the same absolute level of ex-ercise intensity (4,7). This means that asyour level of cardiovascular conditioningimproves you can derive more and moreof the required energy from fat and relyless and less on carbohydrates. This hap-pens because cardiovascular training in-creases the number of mitochondria inmuscle cells and the level of fat-metabo-lizing enzymes (4,7). In other words, thecellular fat-burning machinery is built upand your muscle learns to use less carbsand more fat. This is a great benefit ofregular aerobic exercise. However, itwon’t happen if all you do is walk. In ourexperience here at Parrillo we have seenthat there is an intensity threshold requiredto elicit this metabolic adaptation. Youcan’t get your muscles to grow unlessyou lift intensely, and you can’t train yourmuscles to rely more heavily on fat un-less you do your aerobics intensely. In-tense aerobics will have a much moremarked effect in helping you get lean thanmall walking.

Trust me on this one.An added benefit here is that asyou train your muscles to use a higherproportion of fat in the substrate mix, thisspares muscle glycogen. If you can burnmore fat you don’t need to burn as muchglycogen. So you’ll have more enduranceplus greater strength as your workoutproceeds. Depletion of muscle glycogenis associated with exercise fatigue (4). Theglycogen-sparing effect resulting fromincreased lipid oxidation appears to be animportant mechanism explaining whyaerobic exercise causes an increase inendurance capacity (4). Furthermore,aerobically trained individuals seem tostore more fat inside their muscle cells,as well as increasing their ability for in-tramuscular glycogen accumulation (4).You want to get lean? You want to getpumped? You want to maximize yourstrength and endurance? Do your aero-bics and eat a high carb – low fat diet.You’ll be amazed at the results. Nextmonth we’ll continue our discussion ofcarbohydrates and exercise and talk aboutdietary manipulation of fuel stores and en-ergy substrates. What kind of carbs arebest? When? How much? Stay tuned.

References

1. Flatt JP. Dietary fat, carbohydrate bal-ance, and weight maintenance: effects ofexercise. Am. J. Clin. Nutr. 45: 296-306,1987.

2. Flatt JP. Use and storage of carbohy-drate and fat. Am. J. Clin. Nutr. 61: 952s-959s, 1995.

3. Acheson KJ, Flatt JP, and Jequier E.Glycogen synthesis versus lipogenesisafter a 500 gram carbohydrate meal inman. Metabolism 31: 1234-1240, 1982.

4. Liebman M and Wilkinson JG. Carbo-hydrate metabolism and exercise. Chap-ter 2 from Nutrition in Exercise and Sport,edited by Wolinsky I and Hickson JF, CRCPress, Boca Raton, 1994.

5. Miller GD. Carbohydrates in ultra-en-durance exercise and athletic perfor-mance. Chapter 3 from Nutrition in Exer-cise and Sport, edited by Wolinsky I andHickson JF, CRC Press, Boca Raton,1994.

6. Hargreaves M. Skeletal muscle carbo-hydrate metabolism during exercise.Chapter 2 fromExercise Metabolism, ed-ited by Hargreaves M, Human KineticsPublishers, Champaign, IL, 1995.

7. Coggan AR and Williams BD. Meta-bolic adaptations to endurance training:substrate metabolism during exercise.Chapter 6 fromExercise Metabolism, ed-ited by Hargreaves M, Human KineticsPublishers, Champaign, IL, 1995.

Bulletin #52 – Endurance Performance, Part 2

Scientific BackgroundLast month I explained the conceptsof VO2 max and the lactate threshold. Theseare simply scientific ways of measuring car-diovascular fitness. Briefly, VO2 max is thebody’s maximum rate of oxygen consump-tion (1,2). This determines the maximal in-tensity of aerobic exercise which you cansustain. The lactate threshold is the percent-age of VO2 max at which lactic acid first ap-pears as a waste product in the blood (1,2).Lactic acid is a byproduct of anaerobicmetabolism when glucose is broken downwithout oxygen. Thus the terms “lactatethreshold” or “anaerobic threshold” areoften used interchangeably. This repre-sents the rate of energy production whichcan be sustained aerobically before theanaerobic pathways kick in.These concepts may sound com-plicated but a simple example will make themclear. Let’s take a sedentary person whohasn’t exercised in years and put him on atraining program. Initially he can only ridethe stationary bike for 20 minutes at low in-tensity because he’s so out of shape. Aftersix months of consistent training he can ridefor 20 minutes at high intensity. He has justincreased his VO2 max, his maximal level ofsustainable exercise.

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At the beginning of histraining program if he tried to peddle againsthigh resistance, after a few minutes his thighswould begin to burn and ache from lacticacid accumulation. After six months of train-ing he can peddle for 20 minutes against highresistance with no thigh pain. He has justincreased his lactate threshold.An aerobic exercise training pro-gram will increase both VO2 max and anaero-bic threshold. What does this mean? Themeaning of an increase in VO2 max is prettyobvious: it means you can exercise harder.An increase in anaerobic threshold meansthat you can exercise at a higher percentageof your maximal ability before anaerobic me-tabolism begins to contribute to energy pro-duction. So not only can a trained athleteexercise harder, he can exercise more effi-ciently. He can exercise at a higher percent-age of his maximal ability before the lacticacid burn begins to set in.

That implies hecan maintain a higher percentage of his maxi-mal output for a longer time before reachingfatigue. So now you can see that VO2 maxand anaerobic threshold describe somewhat different aspects of endurance performance.Another fundamental concept we need tounderstand is the respiratory quotient (RQ).This is defined as the ratio of carbon dioxideproduced to oxygen consumed during en-ergy production (1,2). What does this haveto do with anything? It has everything todo with fat loss and body composition.Respiratory quotient is measured by ana-lyzing the amount of oxygen a personextracts from the air and the amount ofcarbon dioxide he exhales into the atmo-sphere as he breathes. We can learn somevery interesting things using this tech-nique. It turns out that if a person is burn-ing pure carbohydrate as his energysource the respiratory quotient is 1.0. Ifhe is burning fat as his fuel source therespiratory quotient is 0.7. This differencecomes from the fact that the carbon at-oms  in carbohydrate molecules are al-ready partially oxidized (the carbon at-oms are bound to oxygen in the sugarmolecule).

In fatty acids the carbon at-oms are bound to hydrogen, and are said tobe “reduced” (the chemical opposite of oxi-dized). It makes sense then that fat shouldcontain more calories per gram than sugar,because in sugar the carbon atoms are al-ready partially oxidized before you eat it. Ina fatty acid molecule the carbon atoms arenot oxidized at all, so when they are burnedinside cells more energy is released per car-bon atom than for glucose. Also, since thecarbohydrate molecule already containssome oxygen atoms built into it, it takes fewermolecules of oxygen to complete its oxida-tion than for a fat molecule. This is the rea-son burning fat as your fuel source resultsin a different respiratory quotient than burn-ing carbs. A typical mixed diet containingprotein, carbs, and some fat results in a RQaround 0.8.Whew! So what does this have todo with bodybuilding and fat loss? By mea-suring the RQ of people while they are exer-cising we can determine the fuel substratewhich is being used. At rest and during sleepmostly fat is used as the body’s fuel source.During low intensity exercise, such as walk-ing or low intensity biking, still mostly fat isused.

At the other extreme, during very highintensity exercise such as weight lifting thepredominant fuel source is carbohydrate.And at moderate exercise intensity a mixtureof fat and carbs is used for fuel. If you thinkabout the biochemical pathways of energyproduction this makes perfect sense. Highintensity exercise like weight lifting is prima-rily fueled by the anaerobic pathway. This isbecause the muscle’s demand for energy isso high that oxygen cannot be supplied tothe muscle fast enough to keep up with thedemand, so the muscle has to turn to anaero-bic metabolism. Anaerobic metabolism cansupply rapid bursts of energy very quickly,but cannot be sustained for a very long time.This is why you can ride the bike for hoursbut can only do squats for about a minutebefore you fatigue. The body can use car-bohydrate as a fuel for anaerobic energy pro-duction (glucose is converted to pyruvatein the glycolytic pathway and pyruvate issubsequently converted to lactate). How-ever, there is no such thing as anaerobic fatmetabolism. Fat requires oxygen to be con-verted to usable energy. Simply put, youcan’t burn fat fast enough to keep up withthe rigorous energy demands of intenseweight lifting, so you have to use carbs.

Onthe other hand, the oxidation of fat makesthe perfect energy source for lower inten-sity exercise such as walking.Many people use this rationale toadvocate low intensity exercise (such aswalking) as the ultimate exercise for fat loss.At first thought, this makes good sense. It istrue that during low intensity exercise ahigher percentage of the energy expendedis derived from fat. The problem is that dur-ing low intensity exercise you burn very fewcalories, so even if almost all of the caloriesare derived from fat, that’s still not much fatloss. During moderate intensity aerobic ex-ercise, such as jogging or a brisk bike rideagainst moderate resistance, a higher per-centage of the calories you burn come fromcarbs, but you burn so many more total calo-ries that the overall result is still greaterfat loss. So it’s not just the percentage ofenergy derived from fat that’s important,but also how many total fat calories youburn. If you do your aerobics at moder-ate to high intensity you will burn morecarbs along with the fat, but you’ll endup burning a greater amount of fat in thelong run because you expend more calo-ries.To put this in perspective, don’t letme leave you with the wrong message.Walking is a great exercise for fat loss,it’s just that you’ll have to walk for hourseveryday to see really noticeable results.I’m not against walking, I just don’t thinkit’s the best choice for serious fat loss.Just as there are plateaus you encounterwhile gaining muscle, you will also hit pla-teaus during fat loss.

Probably the best wayto stimulate accelerated fat loss is to increasethe intensity of your aerobics. In your ownexperience, who’s leaner – the guy who walksthree miles a day or the guy who runs threemiles a day? The runners I know are leanerthan the walkers. I’ve worked with a lot ofbodybuilders who could never really get intocontest shape until they started running.Last month I talked about some ofthe metabolic adaptations that occur as aresult of endurance training. One is an in-crease in the vascular supply to muscles.The harder the muscles are forced to work,the more blood they need. Another impor-tant adaptation is an increase in the fat-burn-ing capacity of muscle cells. Endurance train-ing causes an increase in the cellular contentof mitochondria and enzymes responsible forburning fat. I don’t think you get much of ametabolic adaptation to low intensity exercise.Sure, you can burn fat if you walk longenough, but you really won’t increase yourcapillary density or beef up your fat-burningenzyme pathways significantly unless youtrain hard. The concept of intensity applies toendurance training just like it does to resis-tance training. If you want to see a big changein your body you have to force it to adapt byproviding an intense training stimulus.  

If you still don’t believe me, justtry it. It won’t cost you anything and youhave nothing to lose. Try doing low inten-sity aerobics for a month (walking) and mea-sure your body composition before and af-ter. Then do moderate to high intensity aero-bics for a month (jogging or fairly strenuousbiking) and again measure your body com-position. You’ll see. I’ve done this kind ofthing with competitive bodybuilders abouta zillion times, so I know what will happen.Practical ApplicationsHow do we put this all together toget the best results? Do moderate to highintensity aerobics for 30 to 60 continuousminutes a minimum of three days a week,and seven days a week is better. You shouldbe breathing hard and sweating. Remember,fat metabolism requires oxygen. If you’re notbreathing hard you’re not consuming muchoxygen and so you can’t be burning muchfat. It’s not that complicated. What aboutheart rate? If you want to measure heart rate,that’s fine. Probably between 70-85% of yourtheoretical maximum heart rate is a good goalto both burn fat and accrue the metabolicadaptations of endurance training (increasedcapillary density and increased fat-burningmachinery). Your theoretical maximum heartrate is 220 minus your age.

This is a prettycrude way to do it however because howyour heart rate responds to exercise dependson your level of training.Do your aerobic exercise for at least30 minutes per session. It takes a while toliberate fatty acids from adipose tissue andreally start burning much fat. You probablydon’t burn much fat until about 15 minutesor so into the exercise session. Do your aero-bics on an empty stomach. First thing in themorning before breakfast is a great time. Thenyour glycogen levels are somewhat depletedfrom your overnight fast and insulin levelsare low. Since insulin blocks fat metabolism,aerobic exercise right after eating carbs is abad idea. No carb drinks before or duringyour aerobics. Another good time to do youraerobics is right after weight training. Theweight training depletes your glycogen lev-els so your body will be forced to burn fatinstead of carbs. Also, weight training in-creases catecholamine levels (epinephrineand norepinephrine) which stimulate fat me-tabolism. So you’ll start burning fat rightfrom the start of your aerobic exercise ses-sion that way.The particular type of exercise youdo doesn’t matter. Running, rowing, biking,stair climbing, skiing, in-line skating, and aero-bics classes are all okay. Pick something youlike and can stick with. I suggest mixing it upfor variety. Just make sure you are breathinghard and try to work up a sweat. One tech-nique to help keep the intensity up is circuitaerobics.

Five minutes on the stair climber, fiveminutes on the treadmill, five minutes on thebike, and five minutes on the rowing machine,then repeat the circuit.So we’ve covered the type of exercise,the training intensity, the trainingduration, the training frequency, andthe timing of the training session. Ican’t close without talking a littleabout nutrition. There are four keypoints I’d like to make. First, don’t cut calo-ries too much. If you are faithful to the dietas outlined in the Nutrition Manual, youprobably won’t have to cut calories at all. Ifyou eat according to the diet, do your weighttraining, and do your aerobics, you will au-tomatically get lean without having to cutcalories. If you do need to reduce calories,do so very modestly. Ten percent below yourmaintenance requirement is plenty. If youreduce calories too drastically you will losemuscle, and thereby decrease your metabolicrate and your ability to burn fat. Remember,muscle is the engine that burns fat. Main-taining muscle mass is a priority. Second,eat a low fat diet. The aerobics program asdescribed here is designed to maximize fatburning. If you don’t eat any fat in your diet,then the fat you burn during your aerobicshas to come from stored body fat. If youhave much fat in your diet then when youexercise you’ll simply burn the fat you justate. You’ll be spinning your wheels andwon’t get leaner. If you burn fat during exer-cise, but don’t eat fat, then you’ll have tolose body fat. It’s that simple. Third, getplenty of protein.

This is key to preservingmuscle mass while losing fat. During aero-bic exercise, especially at high intensity,some of the fuel is derived from amino acids.This can result in muscle loss if you’re notcareful. I’ve had very good results using ascoop of Hi-Protein powder before aerobics.This supplies very little carbohydrate anddoes not raise insulin levels significantly. TheHi-Protein increases the blood levels of aminoEndurance Performance, Part IIacids, so that any aminos which are oxidizedduring the exercise session are derived fromthe protein powder instead of being ex-tracted from muscle tissue. Here’s the strat-egy: if you exercise in the morning, get upand have a cup of coffee and a scoop of Hi-Protein powder, then do your aerobics. If youdo your cardio work after weight training,then have a scoop of Hi-Protein between theweight training and the aerobics. This willprevent any loss of muscle tissue and willnot inhibit fat metabolism. Fourth, followyour body composition. All serious body-builders follow their percent body fat andlean body mass. You have to in order to knowwhat’s going on with your body composi-tion. Scale weight is just not enough. TheBody-Stat Kit is an invaluable tool in thisregard. It includes a detailed manual that ex-plains how to modify your diet and exerciseto keep things moving in the right direction,and discusses specific problems commonlyencountered while dieting for contests.Parrillo Performance. We’re here to show youhow.

References

1. McArdle WD, Katch FI, and Katch VL.Exercise Physiology: Energy, Nutrition, andHuman Performance. Lea & Febiger, Phila-delphia, 1991.

2. Wilmore JH and Costill DL. Physiology ofExercise and Sport. Human Kinetics,Champaign, IL, 1994.

Bulletin #37 – Carbohydrates: Mega Fuel For Growth And Energy

Some debate has appeared in thebodybuilding magazines recently aboutwhat’s the best dietary fuel for bodybuild-ers. Some people are advocating the high-fat diet, in which most of the day’s calo-ries are derived from fat while keepingcarbohydrate consumption to a minimum.The rationale for this approach is to avoidcarbohydrates in order to keep insulin lev-els as low as possible, thus promoting useof stored body fat as energy. This is atopic near and dear to my heart, so let’stake a close look at the facts.Let’s begin our analysis with the mostbasic concepts and move to more spe-cific considerations later. What thehigh-carb diet and the high-fat diethave in common is that they bothemphasize consuming adequate pro-tein to maintain positive nitrogenbalance.

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This is the first consider-ation of any bodybuilding diet.Many studies have documentedthat bodybuilders and enduranceathletes need a lot of protein tomake up for the loss of aminoacids which are oxidized asfuel during exercise and torepair muscle tissue which isdamaged during exercise. (See the July‘95 issue of The Parrillo PerformancePress for an extensive reference list.)Most bodybuilders do well on one gramof protein per pound of body weight perday, while others may need as much asone-and-a-half or more.

The primaryfunction of protein in the diet is to supplyamino acids which are used to supportprotein synthesis in the body. This is re-quired to repair muscles that are damagedduring exercise, to support growth of newmuscle tissue, and to allow for proteinturnover, which is the replacement of allsorts of cellular proteins that “wear out”from every day wear and tear.The rest of your daily calorie intakeis to provide energy, and this is where thetwo diets differ. One strategy is to supplymost of this energy in the form of com-plex carbs, while the other approach is tosupply the energy as fat. The truth is thateither approach can be made to work, andthe question is which one works best? Topromote the use of stored body fat asenergy the one crucial requirement whichmust be met is the body must function ina net energy deficit. This means that en-ergy consumed (dietary calories) must beless than the total amount of energy (calo-ries) the body expends. Only when yourbody burns more calories than you con-sume will it draw on stored fat for en-ergy. This is a fine line to walk, however,because if the energy deficit is too greatyou will also draw on stored protein fromskeletal muscle and internal organs forenergy.

This is why it’s important to keepprotein intake high while losing body fat,to minimize these losses. If you are fa-miliar with my program you know that Ido not advocate cutting calories to loseweight, since this slows your metabolicrate and sets into play an adaptive responsethat actually causes your body to hoardfat at the expense of protein (1,2). (Thebiochemistry and endocrinology of thiswere explained in detail in previous is-sues.) A much better way to achieve anenergy deficit is to increase your energyexpenditure by doing more aerobicexercise.You burn fat while doing theaerobics and burn more fat afterwardsbecause your metabolism has increased.So to lose body fat while maintainingmuscle mass we need to consume a dietadequate in protein and deficient in calo-ries (that is, we need to burn more calo-ries than we consume). After meeting theprotein requirement, the rest of the calo-ries can come from carbohydrates, fat,or some combination.  Just so we burnmore calories than we eat, we will losebody fat. So both diets will work, butthat’s not to say they work equally well.I believe that it is best to supply the bulkof dietary energy in the form of com-plex carbohydrates and to keep con-ventional dietary fat to a minimum.

Three general categories of reasonshave lead me in this direction: per-sonal experience with real-life body-builders, general health consider-ations, and the scientific literature.The simple truth is that the vastmajority of bodybuilders stick tothe high-carb approach becausethey have found it works bet-ter for them. Almost all of theprofessionals I’ve trained just seem to dobetter on the high-carb/low-fat diet. Be-lieve me, what matters at this level is re-sults.  If the high-fat diet gave better re-sults, that’s what I would use. But thefact is that in my experience with elite ath-letes the high-carb diet works better.That’s not some fancy technical explana-tion, it’s just the bottom line, plain andsimple.The second reason I favor the lowfat approach is for general reasons of goodhealth. The number one killer of people inthis country is heart disease, which ac-counts for as many deaths as all othercauses of death put together (includingcancer). Coronary artery disease occurswhen cholesterol plaques build up inside the arteries supplying the heart muscle,cutting off some of its blood supply (3).When the heart muscle can’t get enoughoxygen angina (chest pain) occurs.

Some-times the cholesterol plaques rupture(break), causing a blood clot to form inthe coronary artery. This completely cutsoff blood supply to part of the heart re-sulting in myocardial infarction, or a heartattack. Doctors and nutritionists all sug-gest following a low fat diet to help re-duce blood cholesterol level and preventcoronary artery disease. A diet high in con-ventional fat has also been associated withsome cancers, including breast cancer andcolon cancer (3). Furthermore, doctorsand nutritionists suggest eating a low-fatdiet to help lose weight, because gram forgram fat contains more than twice asmany calories as protein or carbohydrate,so cutting down on fat is the easiest wayto cut down on calories. So from the pointof view of general health concerns, suchas heart disease, cancer, and obesity, eat-ing a low-fat diet seems to be the way togo.Finally, there is quite a body of re-search literature supporting carbohydratesas the preferred energy source for ath-letes (see chapters 2,3, and 7 in reference4). In contrast, I don’t know of any sci-entific studies which have found conven-tional fat to be a superior energy sourcefor athletes.

As you know, weight liftingis an anaerobic activity. That means theenergy is produced without using oxygen.Carbohydrate is the body’s preferred fuelsubstrate which can be broken down toyield energy without reacting with oxy-gen. Here’s what’s going on: Let’s sayyou’re doing a set of bench presses tofailure, and you can get 8 reps with 225pounds but you fail on the ninth rep andyour training partner has to help you rackthe weight. Your pecs are working as hardas they can for about 30 seconds and thenthey give out and can’t do another rep.They fail because they run out of energyand because waste products accumulatewhich inhibit further contraction. Whilethis is happening blood is flowing to themuscle supplying it with nutrients andoxygen. The problem is the blood canonly flow so fast, so there’s a limit to howfast it can supply fuel and oxygen. Fur-thermore, it takes some time for thesechemicals to move from the bloodstreaminto muscle cells.When you go for a walk there’s noproblem supplying oxygen and fuel fastenough to keep up with the demands ofyour leg muscles. This is a low intensityexercise and you can keep it up for hoursbecause the blood flow is adequate to sup-ply the muscles with fuel and oxygen asfast as it’s being used. Weight training,on the other hand, is very intense and themuscles are performing work at the fast-est rate they can.  

This means they areconsuming energy as fast as they can—faster than can be supplied by the blood-stream.  So during a set the muscles relyon fuel already stored inside the cell. Thefirst few seconds are fueled by the phos-phate energy system, ATP and creatinephosphate. After that muscle glycogen isbroken down to pyruvate and then to lac-tic acid without reaction with oxygen. Thisbiochemical pathway is called glycolysis,and is a way for muscles to perform workfaster than would be possible if they hadto wait for oxygen to be delivered by theblood. The glycolytic pathway can sup-ply energy for a minute or two, until en-ergy substrates within the cell are depletedand waste products accumulate.The point of all this is that fat cannotbe readily used as a fuel for lifting weightsbecause fat REQUIRES oxygen to be bro-ken down (3,4). Carbohydrates are es-sentially the only fuel your body can useto lift weights, because it’s the preferredfuel the muscles can break down withoutusing oxygen (4). So right off the batthere’s a pretty good reason why body-builders should eat a high carbohydratediet. How can people on the high fat dietstill manage to lift weights?  Because theyare breaking down protein and the aminoacids are converted to glucose in the liverin a process called gluconeogenesis.

Tome it makes more sense to let dietary pro-tein be used as protein instead of beingconverted to glucose (a simple carbohy-drate) so it can be used as fuel. If yourbody requires carbs to lift weights, thenfeed it carbs. Is that so complicated?So high intensity exercise such as lift-ing weights is fueled almost exclusivelyby carbohydrates, while low intensity ex-ercise like walking or riding the station-ary bike can be fueled by carbs or fat.This is why I recommend aerobic exer-cise for bodybuilders: fat oxidation is bynecessity an aerobic activity, so this makesaerobics the best way to lose body fat. Ifyou’re going to do some aerobic exerciseactivity to burn fat, why supply fat in thediet? Would you rather be burning fat thatyou just ate or stored body fat? It makesmore sense to me to supply dietary en-ergy in the form of carbohydrates, whichcan be used as fuel for weight training,and to burn body fat to fuel my aerobicexercise. Why burn 300 calories worthof fat on the stationary bike and then turnaround and eat 300 calories worth of fatyour next meal? That just puts the sameamount of fat right back into your sys-tem. Keep in mind that fat cannot be con-verted into carbohydrate. (Technicallyspeaking, fatty acids cannot be convertedinto carbohydrate, but the glycerol back-bone can.

This only represents a few per-cent of the calories in a triglyceride mol-ecule however.) So you cannot use fat toreplenish glycogen stores.  Neither canfat be converted to protein. Dietary fatcan do two things in your body: it can be burned for energy or it can be stored asbody fat. So if you want to try the highfat diet just keep in mind that you have toburn off all those fat grams or else storethem in adipose tissue. They can’t end upanywhere else.Besides providing energy substratefor weight training, there are several otheradvantages to supplying the bulk of di-etary energy as carbohydrate instead offat. First is that excess carb calories areused to replenish glycogen stores beforethey are converted to fat. Remember, youcan convert carbs to fat, but not fat tocarbs.  If you’re on the high fat diet andconsume too many calories, the excesswill appear as body fat.  That’s the onlymetabolic fate available to it. On the otherhand, if you consume excess calories onthe high carb diet the excess carbs will beconverted to glycogen and stored in themuscles and liver. If the glycogen storesare filled up and you still have more ex-cess carb calories around, then they willbe converted to fat and stored as adiposetissue. Remember, too many calories fromany source can make you fat.

The silverlining to this black cloud is that convert-ing a carbohydrate molecule into a fat mol-ecule takes some energy. In fact, about25% of the energy in a carbohydrate mol-ecule is spent in the process of digestion,assimilation, transport, and conversion tofat. In contrast, only about 3% of the en-Carbohydrates: Mega Fuel For Growth and Energy, Part Iergy in dietary fat is used to get it fromyour mouth to your waist. Calories fromdietary fat are thus stored as body fatmuch more efficiently than are caloriesfrom carbs. Again, carbs sound like abetter deal to me.What got this debate started was theidea that by lowering carbs we couldlower insulin. Since insulin promotes fatstorage and blocks fat breakdown, thisseems like a good idea. What if I told youhow to keep insulin levels low but stillconsume a high carbohydrate diet?Sounds like the best of both worlds. Thefirst thing to do is to choose only com-plex carbohydrate sources and to avoidsimple sugars. The trick is to combine thefoods you eat at each meal so you get aslow release of carbohydrate into your sys-tem so it won’t be turned into fat. Eachmeal should contain at least one servingof  fibrous vegetables, which are digestedand released into the blood slowly. Also,by combining your carbs with protein andCapTri® you can further slow the releaseof carbs. By proper meal combining, asoutlined in the Parrillo Nutrition Manual,you can eat a diet high in complex carbo-hydrates and low in fat and still keep in-sulin at a steady, low level.  Finally, ourcarbohydrate supplement “Pro-Carb™” isspecially formulated to be slow releasing,based on a complex carbohydrate pow-der called maltodextrin.

We’ve blended 4grams of protein along with 22 grams ofcarbs into each serving, which furtherslows digestion. The product contains nosugar or artificial sweeteners. It is forti-fied with amino acids which are requiredin increased amounts during periods ofrapid growth. Pro-Carb™ is the idealsupplement to supply high quality com-plex carbohydrates in a form that digestsslowly, thus minimizing the tendency tostore as fat. Unlike the other carb drinkson the market, ours contains no sugar.Pro-Carb™ is an excellent way to supplycarbs to fuel your workouts, and worksvery well to replenish glycogen stores af-ter training. Take one or two scoops 30-60 minutes before you train and againimmediately when you finish your work-out, and see your intensity and recoveryability skyrocket. Pro-Carb™ also is anexcellent supplement to add quality calo-ries to your meals when you are trying togain muscular weight.

References

1. Bjorntorp P, and Brodoff BN. Obe-sity. J.B. Lippincott Co., Philadelphia,1992.

2. Remington DW, Fisher AG, andParent EA. How to Lower your Fat Ther-mostat. Vitality House International,Provo, 1983.

3. Linder MC. Nutritional Biochem-istry and Metabolism with Clinical Appli-cations. Elsevier Science Publishing Com-pany, New York, 1991.

4. Wolinsky I and Hickson JF. Nutri-tion in Exercise and Sport. CRC Press,Boca Raton, 1994.

Bulletin #12 – Carbs: Ultimate Food Fuel Part IV

In carbohydrate metabolism, therate of glycogen utilization is directly pro-portional to the intensity of the exercise(1).  In other words, the faster the bodyneeds to produce energy, the more it re-lies on carbohydrates.  This is becausefat cannot be metabolized fast enough tomeet the energy demands of high exer-cise.  Furthermore, carbohydrates can bemetabolized to produce energy anaerobi-cally (in the absence of oxygen) while fatmetabolism requires oxygen. Also, dur-ing aerobic metabolism, it takes less oxy-gen to burn carbs than to burn fat.  For agive amount of oxygen, the body can pro-duce more ATP from carbs than from fat.This makes carbohydrate a better fuelsource during intense exercise when oxy-gen is a limiting factor.The respiratory quotient (RQ) isthe ratio of carbon dioxide produced tooxygen consumed. One liter of oxygen isable to produce 5 calories from carbohy-drates but only 4.7 calories from fat (2,3).Since carbohydrates and fat require dif-ferent amounts of oxygen to burn, youcan tell from the respiratory quotientwhat kind of fuel is being used by thebody.  An RQ of 1.0 indicates carbsare being used exclusively for en-ergy (4).Intermediate values ofRQ indicates that a mixtureboth fuels are being used.  Us-ing this sort of measurementduring cycling exercise, re-search found that carbohydrate,when available, is the body’spreferred fuel.  Radioisotopestudies and muscle biopsy as-sessments of energy stores be-fore and after exercise have con-firmed this finding (4).In general, as intensity of exer-cise increases, the relative contri-bution of carbohydrate as the fuelsource increases (1,2).

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Furthermore,a low-carbohydrate diet reduces exercisetime to exhaustion (1).  At rest, musclesrely mostly on fat as their energy source(5).During low intensity exercise (40-50%VO2max) such as walking, the primarymetabolic fuel is fat, while muscle glyco-gen degradation is minimal (1). As theexercise intensity increases, more muscleglycogen is used as fuel. Moderate inten-sity exercise (50-60% VO2max) is fueledby roughly equal amounts of fats and car-bohydrates (2, 4).  At 90-95% VO2max,carbohydrate provides as much as 95%of the energy and the RQ approaches 1.0(1, 2, 4).  Many athletes train at intensi-ties above 70% VO2max which precludesthe use of fat as fuel.Although high-intensity exerciseburns more calories per hour, more ofthose calories come from carbs.  Low-intensity exercise is fueled mostly by fat,but doesn’t burn very many calories perhour. One of the best exercises for losingfat is running. Although running is highintensity and is fueled partially by carbs,it has the additional benefit of loweringyour set point — the amount of fat yourbody is programmed to store.When glycogen stores are limit-ing, the body also draws on amino acidsas fuel (4, 5). The liver can convert mostamino acids into glucose in a processcalled “gluconeogenesis.”  The branchedchain amino acids (BCAAs) leucine, iso-leucine and valine can be oxidized as fueldirectly in the muscles (5).  One studyshowed that as much as much as 57grams of protein — equivalent to the rec-ommended daily allowance — could beburned as fuel during a 10-12 mile run(6).  Lemon and Mullen showed that dur-ing a cycling effort lasting over an hourat 61% VO2max, 10.4% of the energywas derived from protein if the subjectswere in a glycogen-depleted state (7).  Ina glycogen-loaded state, only 4.4% ofenergy derived was from protein.  

Thisis another important reason why body-builders need to ensure adequate carbo-hydrate intake: Carbs have a protein-spar-ing effect, meaning that if adequate carbsare available, they will be used instead ofprotein.  Obviously, bodybuilders wanttheir amino acids to be used for buildingprotein, not as fuel.  Pro-Carb is the ultimate carbo-hydrate supplement.  Carbohydrates area great energy source for fueling athleticactivities and supporting weight gain.Pro-Carb is ideal for carb loading, for useduring training and athletic competitionand as a source of extra calories.  Notonly is it high in carbohydrates, but a Pro-Carb drink also supplies water which isneeded for glycogen storage.  Liquid car-bohydrate meals can be consumed closerto competition than solid foods becauseof their shorter gastric emptying time (2).Liquid meals also produce a low stoolresidue and thus minimize intestinal bulk.Liquid meals are a good way to get calo-ries in without filling up your intestines.Pro-Carb is also an excellent supplementto add extra calories during heavy train-ing.  Pro-Carb utilizes maltodextrin as itscarbohydrate source.  Maltodextrin is acomplex carbohydrate derived fromstarch with a low glycemic index (rang-ing from 22 to 29), meaning that it is re-leased into the bloodstream more slowlythan simple sugars (glucose has a glyce-mic index of 100).  That way, you don’tget a large insulin surge with subsequenthypoglycemia.  Using Pro-Carb, you geta more even energy level because thecarbs are released slowly, minimizing thechance that any will “spill over” into fatstores.  Maltodextrin is a glucose poly-mer, making it ideal for replenishing gly-cogen stores.  Pro-Carb mixes instantlyand tastes great, and contains no simplesugars or artificial sweeteners.  Onescoop provides 22 grams of complexcarbs, 4 grams of high quality protein,with less than a gram of fat.  Mixed without Hi-Protein powder, it makes a balancedliquid meal.

References

1. Sherman, W. Carbohydrates, muscleglycogen, and muscle glycogensupercompensation.  In: Ergogenic aidsin sport, ed. Williams, M. Human Kinet-ics Publishers, 1983

2.  Coleman, E. Carbohydrates: the mas-ter fuel.  In: Sports Nutrition for the 90s,eds. Berning, JR and Stenn, SN.  AspenPublishers, 1991.

3.  Guyton, Textbook of Medical Physi-ology. Published by W.B. Saunders, chap-ter 71, 1976.

4.  Nagle FJ, Basset, DR Jr.  Energy Me-tabolism in Exercise.  In: Nutrition in Ex-ercise and Sports, eds. Hickson, JF andWolinsky, I.  CRC Press, 1989.

5.  Miller, GD and Massaro, EJ.  Carbo-hydrate in ultra-endurance performance.In: Nutrition in Exercise and Sports, eds.Hickson, JF and Wolinsky, I.  CRC Press,1989

6.  Dohm, GL, Williams, RT, Kasparek,GJ and Van Rij, AM.  Increased excre-tion of urea and N-methylhistidine by ratsand humans after a bout of exercise.  JAppl Physiol: Respirat Environ ExcerisePhysiol 52: 27, 1982.

7.  Lemon, PWR and Mullen, JP.  Effectof initial muscle glycogen levels on pro-tein catabolism during exercise.  J ApplPhysiol 48: 624-629, 1980.

Bulletin #10 – Carbs: Ultimate Food Fuel Part II

High intensity exercise of short du-ration, such as weight lifting, relies onthe anaerobic pathway for adenosinetriphosphate (ATP is the fuel sourceused directly by the muscles to powermuscular contractions.) Under theseconditions, only glucose can be used asfuel (1).  Exercise of low to moderateintensity (up to 60 percent of aerobiccapacity) can be fueled almost entirelyaerobically (1).  This means that carbo-hydrate, fat, and amino acids can all beused as fuel for low intensity exercise.Hormones are released into thebloodstream during exercise, and thesepromote fat mobilization and the use offat for energy.  At low to moderate in-tensity exercise, fat and carbohydrateeach supply about half of the energy (1).Fat cannot be metabolized rapidlyenough to meet the energy requirementsof intense exercise (above 70 percentaerobic capacity).  Furthermore, it takesmore oxygen to burn fat than to burncarbohydrate (1,2).  This makes carbo-hydrate a better fuel choice for intenseeffort, when oxygen supply is limited.For a given amount of oxygen, moreenergy can be obtained from carbo-hydrate than from fat.  Muscleglycogen is the fuel source usedfor most forms of exercise, es-pecially weight training.

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 It takes30 to 60 minutes of exercise forfatty acids to be available to themuscles to use as fuel (1).  Upuntil this time, glucose derivedfrom muscle glycogen is the pri-mary fuel.This is why it’s best to doyour aerobics when you’re gly-cogen depleted, and the hor-mones released during exercisehave had time to mobilize fatty ac-ids.  An excellent time for aero-bics is in the morning before break-fast, because you’re glycogen de-pleted then.  And, the longer you spendexercising, the more fat will be used asthe fuel source.Exercise training, especially endur-ance exercise, increases aerobic capac-ity.  As the heart, lungs, and blood sys-tem get bigger and stronger, they candeliver more oxygen to the tissues.  Thisallows relatively more fat to be used ata given level of exercise intensity.  Theanaerobic threshold is the intensity ofeffort at which lactic acid begins to ac-cumulate and is usually expressed as apercentage of aerobic capacity (1).Lactic acid is produced from anaerobicmetabolism of glucose, so the anaero-bic threshold is a measure of how wellyour body is trained for aerobic energyproduction.  

Trained athletes start toaccumulate lactic acid at about 70 per-cent of aerobic capacity, while untrainedindividuals begin to accumulate lacticacid in their blood at about 50 percentaerobic capacity.Furthermore, if aerobically trainedand untrained individuals exercise at therelative intensity (the same % VO2max),the untrained individual will accumulatemore lactic acid in the muscles and bloodthan the trained individual (3).  The dif-ference would be even greater if exer-cise was performed at the same abso-lute oxygen requirement.  This is ex-plained in part by decreased clearanceof lactic acid through the liver by un-trained individuals (3) and also by moreefficient aerobic metabolism of carbo-hydrates and fat in the trained athlete(4).In addition to increasing muscleglycogen storage, endurance trainingalso increases the muscles’ ability to usefat as an energy source.  This increasedability to burn fat spares glycogenstores, thus further increasing endur-ance (4).  Endurance training increasesthe size and number of mitochondria inthe muscles and activates enzymes in-volved in the Krebs cycle and oxidativephosphorylation – the central energyproducing pathways of the body (1,3).

This is one reason why bodybuildersshould engage in aerobic exercise:  Itincreases the ability to burn fat for en-ergy.  This not only helps you stay leanbut also spares glycogen so you can trainharder and longer.Muscle glycogen reserves becomeprogressively lower during exercise.During long bouts of  exercise, glyco-gen reserves may drop to critically lowlevels – to the point of glycogen deple-tion (1).  The athlete then feels ex-hausted and must stop exercising ordramatically reduce the intensity.  Thepoint of muscular fatigue coincides withglycogen depletion (5).  This is sepa-rate from momentary muscular failureat the end of a set which is due to lacticacid accumulation.  Glycogen reservescan also be depleted gradually over a period of days if carbohydrate intakedoes not match that utilized during ex-ercise.  This feeling of fatigue from fail-ure of adequately replenish glycogen re-serves is often interpreted as overtrain-ing.  In some cases, overtraining maybe alleviated by increased carbohydrateconsumption.  Not getting a good pumpin the gym is a clue that you’re prob-ably glycogen deficient.The amount of carbohydrates youtake in affects your training intensity.A group of athletes consuming 300 to350 grams of carbohydrate per day wasseen to become progressively more gly-cogen depleted during successive daysof training (6).  After several days, theseathletes were unable to continue withheavy training.  In contrast, a diet pro-viding 500 to 600 grams carbohydrateper day was seen to result in completerepletion of glycogen reserves, and ath-letes on this diet were able to maintain aheavy training schedule.Of course, these numbers are notprescriptive.  

An individual athlete’s car-bohydrate requirement depends on hisenergy needs, which in turn depend onthe type, intensity, duration, and fre-quency of exercise.  Endurance athletesrequire the most energy and the mostcarbohydrates.  The longer and harderyou train, the more carbohydrate calo-ries you need.Some athletes train so heavily thatthey have trouble consuming enoughhigh carbohydrate foods to fuel their ac-tivities and replenish glycogen stores(1).  Also, consuming a huge volume offood can cause gastrointestinal distress,bloating, or discomfort, and is not con-ducive to optimal exercise performance.  Carbohydrate drinks are veryuseful in this situation, as well as forathletes trying to further increase ca-loric intake.  Carbohydrate beveragesare also useful during training and ath-letic competitions to help maintain en-ergy.  The best carb drinks containslow-release glucose polymers (dex-trins) rather than simple sugars such asglucose, sucrose, or fructose.  This isthe formula contained in our Pro-Carb™powder drink mix made frommaltodextrin, a slow-releasing carbohy-drate. To order Pro-Carb™, simply callour toll-free orderline at 1-800-344-3404.

REFERENCES

1. Coleman,E. Carbohydrates: themaster fuel.  In: Sports Nutrition for the90’s, eds. Berning, JR and Stenn, SN.Aspen Publishers, 1991.

2. Guyton, Textbook of MedicalPhysiology.  Published by W.B.Saunders, chapter 71, 1976.

3. Nagle FJ, Bassett DR Jr. En-ergy Metabolism in Exercise.  In; Nu-trition in Exercise and Sport, eds.Hickson, JF and Wolinsky, I. CRCPress, 1989.

4. Sherman, W. Carbohydrates,muscle glycogen, and muscle glycogensupercompensation.  In: Ergogenic Aidsin Sport, ed.  Williams, M. Human Ki-netics Publishers, 1983.

5. Vander, Sherman, and Luciano,Human Physiology – The Mechanismsof Body Function, p. 236.  Publishedby McGraw-Hill Book Company, 1980.

6. Costill DL, Bowers R, Branam G,Sparks K.  Muscle glycogen utilizationduring prolonged exercise on succes-sive days.  J.  Appl. Physiol. 31: 834-838, 1977.

Bulletin #9 – Carbs: Ultimate Food Fuel Part I

Carbohydrates are grouped into twogeneral classes: complex carbohydratesand simple sugars.  Complex carbohy-drates are nothing more than simple sug-ars linked together into long chains.  Yourbody digests the complex carbs intosimple sugars and releases them into thebloodstream as glucose.  In the end, then,all carbohydrates are converted into glu-cose before they are used.  Based on this,you might think it wouldn”t make any dif-ference whether you get your carbs fromstarch or simple sugars—but it does.Simple sugars are released into thebloodstream immediately, causing a rapidincrease in blood sugar level and an insu-lin surge.  Because simple sugars are re-leased faster than the body can burn themfor energy or store them as glycogen, in-sulin causes the access to be convertedto fat.Complex carbs, on the other hand,must be digested, a process that slowsdown their rate of release into the blood-stream, resulting in a more moderate in-sulin release and a more uniform energylevel.  Also, since they don’t cause as bigan insulin release, complex carbs are notas prone to be converted to fat.  

Parrillo Performance
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Onehundred grams of sugar will have adifferent effect on your body thanone hundred grams of starch, eventhough both supply 100 grams ofcarbohydrate.The Parrillo PerformanceNutrition Program further subdi-vides complex carbs into twoclasses:  starchy carbs and fibrouscarbs.  Good sources of starchycarbohydrates are potatoes, rice,beans, oatmeal, and whole grains,and good sources of fibrous carbsinclude broccoli, lettuce, spinach,green beans, asparagus, and otherfresh vegetables.  On The ParrilloPerformance Nutrition Program, youeat at least one to two servings of starchycarbs and one to two servings of fibrouscarbs at each meal, along with a lean pro-tein source.High fiber foods such as fibrouscarbs contain cellulose, a plant carbohy-drate that humans cannot digest.  Cellu-lose, provides bulk which helps with elimi-nation and is good for your intestines.Also, fiber and protein slow the digestionof starchy carbs, resulting in a moregradual release of glucose into the blood-stream and more sustained energy levels.This way, insulin release is more moder-ate, rather than the sharp spike of insulinreleased in response to simple sugars.When you combine foods in the way rec-ommended by our nutrition program, youhave more energy and less fat storage.Plus, you can eat all the vegetables andsalad greens you want and still stay lean.Be sure to avoid simple sugars.These include not only processed sugarbut also foods like honey, milk, and fruit.Milk contains lactose, or milk sugar.  Fruitcontains a simple sugar known as fruc-tose, which is easily converted to fat inthe liver (1).  Although fresh fruit and lowfat dairy products are healthy, nutritiousfoods, they contain a lot of natural sugarswhich are easily converted into body fat.If you’re striving for ultimate leanness anda high energy level, avoid the consump-tion of sugary foods, including fruit anddairy products.

Animals have a very limited abilityto store carbohydrate and instead rely onfat as the storage form of energy.  Fat is amore efficient way to store energy be-cause it contains nine calories per gram,as compared to four calories per gram incarbohydrate, and because it does not re-quire water for storage, as does carbohy-drate.  Since animals are mo-bile, they store energy as fat.That way, they can store moreenergy in less space and withless weight.Only about 600 gramsof glycogen (the body’s stor-age form of carbohydrate) canbe stored by the human, al-though this probably variesaccording to the individual’straining state, diet, and amountof muscle mass.  Glycogen is storedmostly in the muscles where it will beused, and also to a small extent  in theliver.  Muscle glycogen is not released intothe bloodstream and is only used by the muscle in which it’s stored.After muscle glycogen stores be-come depleted, liver glycogen is brokeninto glucose units and released into thebloodstream for use by working musclesthroughout the body and by the centralnurvous system.  Because the human bodycannot store much carbohydrate, it isvery important, especially for athletes, toregularly consume a diet high in complexcarbohydrates to fuel the body.

Many experiments indicate that car-bohydrate is the body’s preferred fuelduring exercise.  More than 99 percent ofthe carbohydrate is used in the body toform adenosine triphosphate, or ATP (2).ATP is the fuel source used directly bythe muscles to power contractions.  ATPis not stored by the body so it must beconstantly produced from the aerobicmetabolism of carbohydrates, fatty acids,and amino acids (aerobic means “withoxygen”).Carbohydrate is unique in that it canalso be metabolized anaerobically (with-out oxygen).  The anaerobic productionof ATP from carbohydrate is called gly-colysis.  Glycolysis makes a big contri-bution to the energy expended during veryintense exercise of short duration, suchas weight lifting.  Lifting weights requiresso much energy so fast that aerobic me-tabolism can’t keep up with the demand.By the time oxygen can get from the lungsto the muscles and inside the cells, yourset is already over.Although glycolysis is relatively in-efficient, it offers the advantage of gen-erating energy instantly upon demand.One disadvantage of anaerobic metabo-lism is that it produces lactic acid as awaste product.  Lactic acid accumulatesinthe muscles and the blood and is respon-sible for the burning sensation at the endof the set.  

The accumulation of lacticacid shuts down energy production andforces you to stop and rest.  Most of thelactic acid makes its way from themuscles into the bloodstream.  The liveris able to convert the lactic acid back intoglucose so it can be used as fuel again.The conversion of lactic acid back intoglucose requires oxygen, and this is whyyou continue to breathe hard for a fewminutes while you’re recovering after aset.  This pay-back from anaerobic me-tabolism is called “oxygen dept.”In conclusion, your body likes toburn carbs for energy and to store en-ergy as fat.  Generally speaking, the morecarbs you eat, the more carbs your bodywill burn for energy, and the more fat youeat, the more fat you’ll store.  This is whyathletes—and especially bodybuilders—should eat a diet high in complex carbo-hydrates and low in fat,  In fact, anyoneinterested in having a lean, high-energybody should consume a high-carbohy-drate, low-fat diet.  We also recommendcarbohydrate supplementation with Pro-Carb™, which is formulated withmaltodextrin, a slow-releasing carbohy-drate.  Not only is it high in carbohydrates,but a Pro-Carb™ drink also supplies wa-ter which is needed for glycogen storage.To order Pro-Carb™, call our toll-freenumber at 1-800-344-3404.

REFERENCES

1.  Shafrir E. Fructose/sucrose me-tabolism, it’s physiological and pathologi-cal implications.  In: Sugars and Sweet-eners, Kretchmer N and Hollenbeck CB,eds.  CRC Press, 1991.

2.  Pate, TD and Brunn, JC.  Fun-damentals of carbohydrate metabolism.In: Nutrition in Exercise and Sport, eds.Hickson, JF and Wolinsky, I.  CRC Press,1989.3.  Zubay, Biochemistry.  Addison-WesleyPublishing Company, 1983.