DiPasquale vs. McDonald on Fat

Diet and Nutrition
1

When reading through some of Lyle McDonald’s work, I came across a section that piqued my interest. From McDonald’s own website “BodyRecomposition.com”, he states in his Baseline Diet Article:

www.bodyrecomposition.com/Articles/baseline2.html

While he doesn’t name DiPasquale by name, I know McDonald is familiar with his work and I can’t see how this could apply to anything but the Anabolic/Metabolic Diet (the well-meaning individual being Mauro DiPasquale).

It seems as though McDonald is refuting the central theme of the Metabolic Diet, which is that your body will adapt to become a fat-burning instead of carb-burning machine.

I could see this debate going two ways. While I haven’t read the primary literature, DiPasquale seems confident that lipolysis is increased on a high fat diet. I think McDonald is arguing that a high-fat diet would decrease training performance by depriving the body of available glucose. I think he would say that performance will necessarily be stunted due to the inability to properly load, and that while it is true that fat will be better and more quickly utilized in a general way, that it will not benefit a person in the short bursts that make up weight training.

Frankly, this is the point where my formal dietary training exceeds me. I have a fairly strong background in biology, but I simply don’t feel qualified to complete this argument or come down one side or the other. In fact, I may have misconstrued the argument all together. What I am quite sure of however, is that McDonald does feel there is an argument.

My gut instinct is to assume that Dr. DiPasquale, with his background would not miss something obvious and McDonald might just be making a little error. Of course, DiPasquale has build up a little brand name here so who can say.

I was hoping someone could come in and try to resolve the issue or at least throw a little light on the problem as I have not read anything by McDonald that addressed this issue directly.

2

Your liver breaks down triglycerides and converts the glycerol into glucose by a process called gluconeogenesis. That is the fuel your body uses during exercise. Fatty acids can be oxidized directly then. So your body is never really running of of “fat.”

No conflict.

Edit: Technically your muscles run off of ATP. Both glucose and fatty acids are sources of ATP, so your body doesn’t run directly off of either one. Both glucose and fatty acids enter the mitochondrea and are converted to acetyl CoA molecules. Glucose yields about 36 ATP while a 16 carbon fatty acid can yield 129 ATP.

Both authors have gotten results, so I don’ think it’s that big of a deal.

3

FYI, I found that Lyle has a forum of his own, so maybe I’ll get a reply and he’ll be able to inform us all.

There thread on his forums: forums.lylemcdonald.com/showthread.php?p=698#post698

4

[quote]Brant_Drake wrote:
Your liver breaks down triglycerides and converts the glycerol into glucose by a process called gluconeogenesis. That is the fuel your body uses during exercise. Fatty acids can be oxidized directly then. So your body is never really running of of “fat.”

No conflict.

Edit: Technically your muscles run off of ATP. Both glucose and fatty acids are sources of ATP, so your body doesn’t run directly off of either one. Both glucose and fatty acids enter the mitochondrea and are converted to acetyl CoA molecules. Glucose yields about 36 ATP while a 16 carbon fatty acid can yield 129 ATP.

Both authors have gotten results, so I don’ think it’s that big of a deal.[/quote]

Sigh…there is CLEARLY a conflict. Whether or not McDonald is right is another issue.

And yes, both glucose and FFAs are sources of ATP. However, FFAs take a longer time to convert to FFAs and glucose derived from carbohydrate sources is more accessible. I think McDonald is arguing that the glycolytic process that would be used for weight-training would not cause fat to be utilized, and there would be no way that it would be used “preferentially”, as DiPasquale claims.

As to whether they’ve both gotten results…who gives a crap? That wasn’t the point of the thread.

5

[quote]Fiction wrote:
FYI, I found that Lyle has a forum of his own, so maybe I’ll get a reply and he’ll be able to inform us all.

There thread on his forums: forums.lylemcdonald.com/showthread.php?p=698#post698[/quote]

Brant Drake’s answer is correct. That is the mechanism people are talking about for short, intenese, anaerobic bursts of exercise [lifting, sprinting, etc…] There is no DIRECT tapping into fat for this type of exercise but there can be INDIRECT

6

[quote]Fiction wrote:
Brant_Drake wrote:
Your liver breaks down triglycerides and converts the glycerol into glucose by a process called gluconeogenesis. That is the fuel your body uses during exercise. Fatty acids can be oxidized directly then. So your body is never really running of of “fat.”

No conflict.

Edit: Technically your muscles run off of ATP. Both glucose and fatty acids are sources of ATP, so your body doesn’t run directly off of either one. Both glucose and fatty acids enter the mitochondrea and are converted to acetyl CoA molecules. Glucose yields about 36 ATP while a 16 carbon fatty acid can yield 129 ATP.

Both authors have gotten results, so I don’ think it’s that big of a deal.

Sigh…there is CLEARLY a conflict. Whether or not McDonald is right is another issue.

And yes, both glucose and FFAs are sources of ATP. However, FFAs take a longer time to convert to FFAs and glucose derived from carbohydrate sources is more accessible. I think McDonald is arguing that the glycolytic process that would be used for weight-training would not cause fat to be utilized, and there would be no way that it would be used “preferentially”, as DiPasquale claims.

As to whether they’ve both gotten results…who gives a crap? That wasn’t the point of the thread.[/quote]

hmmm…if you get a response from Lyle, I’d be interested in what he said

7

[quote]jsbrook wrote:
hmmm…if you get a response from Lyle, I’d be interested in what he said[/quote]

Will do. It appears he posts there daily.

8

My point was that your body does not run DIRECTLY off of glucose or fats, that they are the first step in a process that ends up in the same place.

Also, your body never runs 100% off of either, there is always some synergy.

Add the fact that glucose is being produced from fatty acids, there is room for both to be correct.

Lyle: “Glucose in the cell is what is used during exercise.”

MD: “Glycerol is converted to glucose and then moved into the cell where it is used, but it all starts with fat.”

Do you see what I mean?

9

[quote]Brant_Drake wrote:
My point was that your body does not run DIRECTLY off of glucose or fats, that they are the first step in a process that ends up in the same place. [/quote]

Partially right. Your body runs off ATP, as you said, which is derived from glucose, which can be derived from either dietary protein, fat, or carbohydrates. While it’s true that they CAN end up in the same place, it doesn’t mean that the process to get there is the same nor does it mean that certain substances aren’t used preferentially.

Not necessarily. For example, when you do a 1 RM on the squat, you are not using any fat–it is all ATP. That is the point–even though fat CAN be utilized, it is made available slower. As Lyle noted, unless your sets are going for 3+ minutes, you’re not using fat.

[quote]Add the fact that glucose is being produced from fatty acids, there is room for both to be correct.

Lyle: “Glucose in the cell is what is used during exercise.”

MD: “Glycerol is converted to glucose and then moved into the cell where it is used, but it all starts with fat.”[/quote]

Yes, in this sense they ARE both correct, but this is not where the conflict lies I am quite sure. And there IS a conflict.

10

There are cho loads with the AD after all for this purpose.

11

Lyle’s response was oddly defensive–I’m not quite sure why. He made two responses, but I am condensing his writing into on for brevity:

[quote]depending on the type of lifting being done (i.e. purely low rep work vs higher rep bodybuilding work), lowcarb diets may affect performance. whether or not lipolysis is enhacned on lowcarbs (and it is) is irrelevant because:

anaerobic activities such as weight training can’t use fat for fuel as

a. fat can’t be oxidized without sufficient O2 (by definition not avaialble during anaerobic activities)
b. even if it could (which it can’t), fat metabolism can’t provide atp fast enough

fat cannot be oxidized under anaerobic conditions, I’d add that fat is oxidized in mitochondria, which is something that Type II fibers (the primary target of weight trainig) generally have low levels of.

this tends to be less of an issue for folks doing purely low rep work (where ATP/CP is the primary energy system) but for bodybuilders who typically muscle glycogen will sap generally intensity

there is also evidence that depleted glycogen harms expression of hte genes that stimulate hypertrophy (abstract below).[/quote]

He cites: http://www.ncbi.nlm.nih.gov/entrez/utils/fref.fcgi?PrId=3051&itool=AbstractPlus-def&uid=17218424&db=pubmed&url=http://jap.physiology.org/cgi/pmidlookup?view=long&pmid=17218424

His opinion as to why MD missed this is:

So the conflict appears to be that Lyle feels that bodybuilders and other athletes pursuing hypertrophy would be disadvantaged because the Anabolic/Metabolic Diet would rob them of the needed intensity to get the desired results.

This doesn’t sit well with me though. It seems to me that the body can typically hold 1500-2000 kcal in muscle glycogen. The body would mobilize fat during the period in between workouts to restore muscle glycogen to adequate levels, more than enough to provide for an exercise bout lasting approx. 60 minutes, making the performance issue not a problem. No new glycogen needs to be made DURING the training session, so I’m not sure that there is a problem.

I think Lyle assumes that glycogen would be depleted in an Anabolic Diet athlete, and I’m not sure that that is the case. If it is, then he would be right, and the study would further support his findings. If not, then the study is irrelevant and I don’t think his criticism is well founded.

12

Glycerol can be converted into glucose in the liver, but it is subsequently stored in the liver. Liver glycogen provides little support for short-term aerobic exercise like bodybuilding. It will certainly help maintain an overall level of energy, but not immediately to prolong a set. In the absence of carbs in the diet, glycerol is heavily relied upon for neural function, as the brain and nervous system require a large amount of carbohydrates to function. On top of that, glycerol is incorporated into phospholipids. Point is, it doesn’t do much to aid in bodybuilding.

13

Someone on the AD will typically take in 500-1000g of CHO on a carb load, so this is really a moot point. The only time when your workout might be “compromised” is your Thursday or Friday workout, and MD suggest making those lighter workouts anyway.

14

[quote]Schwarzenegger wrote:
Glycerol can be converted into glucose in the liver, but it is subsequently stored in the liver. Liver glycogen provides little support for short-term aerobic exercise like bodybuilding. It will certainly help maintain an overall level of energy, but not immediately to prolong a set. In the absence of carbs in the diet, glycerol is heavily relied upon for neural function, as the brain and nervous system require a large amount of carbohydrates to function. On top of that, glycerol is incorporated into phospholipids. Point is, it doesn’t do much to aid in bodybuilding.[/quote]

I see, so the glycerol from fat that converts to glucose and subsequently glycogen would not be available for the muscles and thus diminish muscular performance in prolonged sets? i.e. MD is mistaken?

Would the prescribed “carb-loading” on the weekends compensate for this?

15

Yes, you are correct. Liver glycogen will aid in aerobic activity, as the glycogen can be released into the blood and then used by the muscles. But this transportation process is too slow to aid in prolonging anaerobic exercise that relies only on stored ATP/CP and muscle glycogen.

DoubleSidedTape is correct in that the carb load is designed to replenish muscle glycogen. After adapting to a low-carb diet, which would result in a carb-sparing effect, most of the carbs you eat will be saved for only the most intense activities you perform (in this case working out).

Ultimately though, the AD or any low-carb diet limits high-intensity athletic performance. The only two scenarios where they may not be any detriment (but also no real benefit) are low-intensity prolonged endurance activities and super-high intensity weightlifting activities (as in 3-5 reps per set with etended rest periods).

16

I think I read this whole thread correctly and there seems to be something being left out, but I could be wrong about this:

Can’t you regenerate ATP (aerobically)between sets of high intensity exercise (which is ATP fueled more directly by glycogen)?

So there’s the first point of having a pretty hefty store of muscle glycogen in the first place.

And secondly, I could do one set of 8 very intense repetitions, and while I’m resting for my next set, my body could be using fatty acids to replenish glycogen/ATP stores.

Again, I am not formally trained in this stuff, but this makes sense to me, for now.

17

The only thing i’ll say is this. Mauro was/is a powerlifer…and was a good one.

Lyle looks like an IT guy.

18

ATP/CP stores can regenerate between sets, though maximum ATP/CP stores afford between 5-10 seconds of maximum muscular contraction. Muscle glycogen can be used anaerobically to produce ATP very quickly, but this results in lactate buildup (which must be removed during rest). This anaerobic metabolism allows for long sets of muscular effort between 30-90 seconds. The problem with low-carb diets (once carb-depleted after a couple days without carbs) is that the muscle glycogen just isn’t there in sufficient quantities. Thus strength training can rely mostly only on the ATP/CP energy system, which means that anything over a could (3-5) quick reps and you’re performance will begin to tank.

Fat can be used for energy, but requires oxygen (aerobic metabolism). It can not be used without available oxygen (this is why VO2 max is important to endurance athletes). ATP/CP is restored between sets using various sources (fats, carbs, etc.), and you’ll notice on a low-carb diet that it takes longer between sets to recover ATP/CP stores, due to the adaption to fat metabolism. The difference between carb-rich and carb-poor diets on ATP/CP resynthesis is actually not that significant, but the time to exhaustion with maximum exercise is (for reasons in the first paragraph).

I hope this makes some sense.

19

Makes sense.

Do you think muscle glycogen won’t be restored between sets? (unlike ATP as you’ve pointed out)

20

No, glycogen will not be “restored” or synthesized.

If you’re not taking in any exogenous glucose or your body doesn’t have enough plasma glucose and the muscles do not have enough glucose available, there won’t be any glycogen stored.