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Bulletin #48 – Exploring The High Fat Diet, Part 2

As I mentioned in Part I of thisseries last month, any energy deficient dietwill result in fat loss. So the high fat dietwill work for weight loss, providing youeat fewer calories than you burn (it hasto). The biggest problem comes duringweight gain. There are several big theo-retical problems with using the high fatapproach for weight gain. First is the factthat insulin is the most important anabolichormone in the body, and on these cyclicdiets we only get the benefit of insulinaround two days every week. Second isthat during energy excess (that is, duringweight gain) excess dietary fat is prefer-entially stored as body fat. There is nobiochemical pathway in the human bodyfor converting fat into carbohydrate, soexcess dietary fat cannot be stored as gly-cogen. Fatty acids cannot be incorporatedinto protein either. Possibly the carbonsderived from fatty acid metabolism couldbe used to build the carbon skeleton ofnonessential amino acids, but since fattyacids do not contain nitrogen, a nitrogenfrom the pre-existing amino acid poolwould have to be donated to form a newamino acid molecule.

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Therefore, net pro-tein synthesis cannot occur from fat.Thus, dietary fat really has only two quan-titatively significant metabolic fates: to beused as energy or be stored as body fat.(Of course, dietary fats are also used toform structural components of cell mem-branes, steroid hormones, eicosanoids,and many other extremely important bio-logically active molecules, but this ac-counts for only a tiny fraction of ingestedfat, especially during a high fat diet.) Sincedietary fat cannot be converted to proteinor glycogen, excess dietary fat can onlybe stored as fat. By definition, duringweight gain we must be in a calorie sur-plus. This means that not all of the in-gested fat can be burned as fuel, sincewe are by definition consuming an excessof fuel. To gain weight you must con-sume more calories than you expend(simple thermodynamics) and if thoseexcess calories are supplied in the formof dietary fat, then it seems inescapablethat they must be stored as fat.So where have we come so far?The high fat-low carb approach has a goodtheoretical basis for working to maximizefat loss while on an energy deficient diet,but would be expected to result in fat gainduring an energy sur-plus. This leads to ageneral principle inbodybuilding nutrition:Diet composition ismore critical duringweight gain thanweight loss. Duringweight loss, you willbe in an energy deficit.Over a 24 hour periodessentially all of the fatand carbs you eat willbe burned as fuel.

Theprotein that you eatwill be used to main-tain protein tissues andto replenish worn outenzymes and otherprotein cellular com-ponents (that is, for protein turnover). Anyextra dietary protein left over will also beused as fuel. Finally, body fat will also beused as fuel to supply whatever amountof expended energy was not supplied bythe diet. So when you’re in an energy(calorie) deficit, it does matter that youget enough protein, but after that the pre-eminent consideration is just how muchenergy you consume. As a first approxi-mation, it appears as if it doesn’t matterthat much if you supply the rest of theenergy as carbs or fat or some mixture ofthe two, because it’s all going to be burnedanyway. (Actually, it does matter, but I’llget to that later.) So during weight loss allof the food you eat will be burned for fuel,and none of it will be retained by the body(except some protein). During weightgain, on the other hand, diet compositionis everything.

As explained above, if youconsume excess energy in the form of(conventional) dietary fat, it is extremelyprone to be stored as body fat (1-13).Although I’ve had good success with lowcarb diets to lose fat, I’ve never had goodresults from low carb diets in terms ofgaining muscle. I think you need insulin,which seems to have asynergistic interactionwith growth hormoneand testosterone, to geta good anabolic effect.Now back tothe issue of diet com-position during weightloss. Like I said above,after meeting your pro-tein requirement thenext most importantthing is how manycalories you consume.You will lose weight re-gardless of how thosecalories are supplied solong as you maintain anenergy deficit. But notall weight loss is cre-ated equal. Really we’re not interested inweight loss per se but in fat loss, and wewant to preserve as much muscle duringthe diet as possible. Serious bodybuilderscarefully follow their body composition(using a tool such as The Parrillo BodyStatKit) during their diets to make sure they’relosing fat and not muscle. Adjustmentsare made along the way to keep thingsmoving in the right direction. While dietcomposition has only a minor effect onoverall weight loss, it has a more substan-tial effect on determining how much ofthat weight is fat versus muscle.

Whatwe’re trying to do here is prevent muscleloss. In my experience with bodybuild-ers, carbs work better than fat to spareprotein (the technical term for preventingthe use of protein as fuel) during energy restricted diets. In other words, both ap-proaches (the high fat diet and the highercarb diet) work in terms of losing fat, butthe higher carb diet results in less muscleloss during the diet. Overall, you end upleaner (lower percent body fat) becauseyou have more lean body mass remainingafter you’ve lost the fat. Why is this? Thebiochemistry is fairly straight-forward.The brain’s preferred fuel is glucose, andyour body will go to extraordinary mea-sures to provide glucose for the brain. (Af-ter several days of glucose deprivation,the brain can adapt and switch over touse ketones as fuel, but this is not it’s pre-ferred choice.) Following a very low carbdiet, liver glycogen stores are depleted inabout a day or two. (Note: muscle glyco-gen can only be used as fuel by the muscle,and cannot be released back into thebloodstream for use by the brain. Musclecells lack the glucose phosphatase enzymeneeded to release glucose stored as gly-cogen back into the blood. Therefore, onlyliver glycogen is available to help main-tain blood glucose levels.) Therefore, af-ter a day or so of severe carb depletionblood glucose levels begin to fall. Unfor-tunately, fatty acids cannot be convertedto glucose by humans (although bears can,and this is why they can hibernate). Thebody has another way of maintaining bloodglucose levels, however, and this is tobreak down skeletal muscle protein (andvisceral, or organ, proteins too, for thatmatter).

The muscle proteins are brokendown into their constituent amino acids,the amino group is then removed formingan alpha-keto-acid, and these “carbonskeletons” of amino acids are transportedto the liver which can use them to makeglucose. To sum up, if you use a low fat-moderate carb diet to lose weight yourbody doesn’t have to break down muscleto convert amino acids into glucose, be-cause you’re getting enough glucose inthe diet. If, however, you use an extremelylow carb diet you will necessarily breakdown some muscle. This catabolic pro-cess is reduced during ketosis, but it takesabout two days or so of carb restrictionto get into ketosis. So there will be twodays during every seven day cycle whenyou’re breaking down muscle.Another problem with the verylow carb approach is that energy levelsfall dramatically. Recall that anaerobicexercise, such as weight lifting, is fueledalmost exclusively by carbs.

Fat cannotbe used as an anaerobic energy source, itcan only be oxidized aerobically. There-fore strength and energy levels fall dra-matically without carbs. This results inmore muscle catabolism, as the musclesturn to branched chain amino acids asfuel.There are also several technicalaspects of energy metabolism that sug-gest severe carb restriction might not bethe best way to go. Low carbohydratediets have been found to reduce thyroidhormone level, which is one of the chiefcontrollers of metabolic rate. After a pe-riod of carbohydrate restriction (probablyon the order of several weeks to a coupleof months) you will likely find your weightloss plateaus. This is probably due to de-creased thyroid level and decreased meta-bolic rate. The only real cure for this (be-sides taking thyroid medication) is to in-crease calories and add some carbs backto your diet. Unfortunately, since yourmetabolic rate is slow and your thyroidhormone level is low, when you do thisyour body is primed for fat storage andyou’ll likely put on a few pounds of fat.Also, there’s the issue of thermogenesis.After you eat a meal some portion of thedietary energy is released as body heat.This process is called diet-induced ther-mogenesis (DIT) and the amount of heatenergy released is called the thermic ef-fect of feeding (TEF).

Protein and carbo-hydrate both have a significant ther-mogenic effect, but (conventional) dietaryfat has virtually no thermogenic effect.Carbohydrate feeding stimulates thesympathetic nervous system which in-creases metabolic rate. What this meansis that for a given level of energy intake(caloric consumption) more of the foodenergy will be given off as heat if youeat a high carb diet as compared to ahigh fat diet. With the high fat diet lessof the food energy is lost as heat, leav-ing more available for use as fuel (or evenworse, for storage as body fat). If moredietary energy is available for use as fuel,then you’ll burn less body fat as fuel.Energetic and metabolic considerationsexplain why most people get better re-sults using a higher carb diet.So are there any useful lessonswe can learn from this? You bet thereare, some very important ones that canpropel you to the next level of physiquedevelopment. First off, notice that it’snot the carbohydrates themselves thatmake fat loss more difficult, but ratherthe insulin release they induce. Insulin in-hibits lipolysis, not carbs per se. There-fore, by proper food selection and mealstructuring we can do a lot to reduce in-sulin levels and still be able to eat somecarbs. First off, avoid all simple sugars,including not only refined sugar andsweets but also foods that contain naturalsugars such as fruit, juice, dairy products,honey, and syrup. Limit your carbohydrateselections to natural, unrefined, complexcarbohydrates such as potatoes, rice, andvegetables. Avoid refined carbohydratessuch as bread and pasta. Always consumeyour carbs with protein, and make sureto eat plenty fibrous carbohydrates, such as brocolli, cauliflower, asparagus, greenbeans and other salad vegetables, alongwith your starches.

These measures dra-matically slow the rate of release of glu-cose into your bloodstream, which helpskeep insulin levels low. Eat many smallfrequent meals instead of a few big ones,for the same reason. Also, as you getleaner gradually consume less starches andmore vegetables. Start by eliminatingstarch from your last meal of the day.During the last week or two you may vir-tually eliminate starches, but you can stilleat vegetables.So does the high fat-low carbapproach have anything going for it? Youbet it does. The strategy of reducing carbsto lower insulin and stimulate fat burningreally works. I’ve used this approachmyself and it works very well, especiallywith endomorphic type people who havea hard time losing fat. Like I said in thebeginning, my point is not to insult theauthors of the high fat diets. But there aretheoretical reasons having to do with en-ergy metabolism, thermogenesis, endocri-nology, and protein catabolism (see above)which explain why reducing carbs toomuch is not a good idea. The ideal ap-proach would be if we could combine thebest aspects of both diets to generatesomething even better. Technology hasmade this possible, with the developmentof CapTri®.

CapTri® is a specially engi-neered fat, and by incorporating it in thediet in place of starchy carbohydrates wecan lower insulin levels and achieve thefat burning effect of the high fat diets.It’s unique molecular structure overcomesthe problems of conventional dietary fats,making it the ideal energy source for body-builders. For example, CapTri® has vir-tually no tendency to be stored as bodyfat (14,15). It is metabolized in the liverwhere it is converted to ketones whichthen are used as fuel by muscles (14,15).It has a very high thermogenic effect andis converted into energy much morereadily than regular fat. Since it is rapidlyused for energy it has very little tendencyto be stored as body fat. CapTri® is con-verted into ketones, which block proteincatabolism. In fact, CapTri, unlike otherfats, can be digested and converted intoketones even when there are ample carbsalready in the system. In short, CapTri®allows us to reap the benefits of the highfat approach without the problems thatgo along with conventional dietary fat.To use CapTri® during fat loss, keep yourprotein intake high at about one to 1.5grams per pound of body weight per day,then reduce carbohydrate intake and pro-vide an equivalent number of calories fromCapTri®. For example, if you normallyconsume 300 grams of carbs per day(1200 calories worth), reduce that to 150grams per day and add 5 tablespoons ofCapTri® per day (providing 570 calories).A good way to gauge how far to reducecarbs is to gradually decrease them untilyou find that you lose your pump aboutone-half to two-thirds of the way throughyour workout.

This means that glycogenstores are depleted, and this is where youwant to be for maximum fat loss. TheCapTri® diet allows you to reduce carbswithout cutting calories, which wouldslow your metabolism and cause muscleloss. Many people find they don’t need toreduce caloric intake below maintenancewhile using this regimen since the ther-mogenic effect of CapTri® provides a“built in” energy deficit (more of the di-etary energy contained in CapTri® is lostas body heat than for regular foods). Thisapproach allows you to reduce carbs with-out having to use regular dietary fat as anenergy source. I have a problem going aslow in carbs as the other diets recom-mend. I think you should eat some carbsso you can continue to perform intensetraining while you diet. Plus, if you’ve evertried the near-zero-carb diet you know thatit makes you feel like death. By reducingcarbs and always combining your starcheswith protein, vegetables, and CapTri® ateach meal, you will dramatically reduceinsulin levels and maximize fat loss. Un-like conventional fats, CapTri® alsoworks well during weight gain because itdoesn’t contribute to fat stores (14,15).The Parrillo Performance NutritionManual contains much more detailed in-formation about how to design your dietfor maximum muscle gain and fat loss. Ifyou want more information on CapTri®call and request our CapTri® TechnicalReports.I expect over the next few yearsdrugs will become relatively less impor-tant in bodybuilding and precision nutri-tion and supplementation will becomemore important. The next generation ofCapTri® will undoubtedly help propeltomorrow’s competitors to the next level.


1. Horton TJ, Drougas H, Brachey A,Reed GW, Peters JC, and Hill JO. Fat andcarbohydrate overfeeding in humans: dif-ferent effects on energy storage. Am. J.Clin. Nutr. 62: 19-29, 1995.

2. Flatt JP. Importance of nutrient balancein body weight regulation. Diabetes/Me-tabolism Reviews 4: 571-581, 1988.

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

4. Hill JO, Peters JC, Reed GW, SchlundtDG, Sharp T, and Greene HL. Nutrientbalance in humans: effects of diet com-position. Am. J. Clin. Nutr. 54: 10-17,1991.

2018-03-13T11:10:36-04:00 May 29th, 2009|Technical Supplement Bulletins|

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