Art De Vany: Negatives, Protein Requirements, and Turnover

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Negatives, Protein Requirements, and Turnover

November 20, 2006 08:37 PM

An odd fact about exercise and protein requirements is this: aerobic exercise increases your protein needs. Anaerobic exercise decreases them. How could this be true?

The answer also explains why aerobic training diminishes muscle mass.

It isn't that hard, when you understand exercise theory at the Evolutionary Fitness level.

Aerobic exercise uses protein as an energy substrate; it burns protein to supply energy for aerobic exercise. It also diminishes the insulin response to protein intake. Anaerobic exercise induces protein sparing through the release of GH, the protein-sparing hormone. Consequently, aerobic exercisers require more protein than anaerobic exercisers do [W. Evans, Protein Nutrition, Exercise, and Aging: Review in Journal of American College of Nutrition, Vol. 23 (2004)].

Even older people, whose dietary intake of food is limited, require 1.6 g of protein per kilogram of body mass per day. Few, if any, take in this amount. The RDA for older people is half that. Pitiful, I say. Aerobic exercise at the RDA will lead to sacropenia, impoverished muscle mass and poor body composition.

A brief look at the evolutionary evidence would be enough to demonstrate this latest discovery of exercise and nutrition science. But, we already knew this. Our ancestors did little of what passes for aerobic exercise. They walked and engaged in intermittent, intense activities. They got plenty of rest and play. They did not jog or run 10Ks, except for fun and to demonstrate their fitness to others.

Since about half or more of their caloric intake was in wild animal sources, they had protein far beyond the RDA. If you combine aerobic exercise, and no anaerobic, high intensity activities...

and live on the RDA, you will lose muscle mass throughout your life. That is one of the primary reasons for the so-called age-related sarcopenia that most of people evidence. They develop a lower rate of protein turnover; the pool of protein in the lean body mass is reduced and the rate of intake and excretion is diminished.

It does not have to happen. Our ancestors did not lose muscle mass at a rate comparable to modern humans, nor do I and other followers of Evolutionary Fitness. Lifting and lowering weight induces muscle micro-damage. This increases muscle and protein synthesis and whole body protein mass. Shortening the muscle in the eccentric phase tears fibers, induces GH release, and increases RNA synthesis and muscle gene expression while it reduces protein loss per gram of muscle mass. The result is increased protein mass, ie. muscle. The body's response to protein intake in the post-exercise state is increased insulin secretion and an anabolic state.

In contrast, aerobic exercise induces protein metabolism, lower protein and muscle mass, low insulin response to protein intake, and aging in the form of sarcopenia (a fancy word for poor body composition).

And you wonder why I emphasize eccentric moves in my workouts.

· Evolutionary Fitness

Comments

Elam, flight wouldn't be considered an aerobic activity, one is sprinting from danger not jogging from it. Also, strictly speaking, increasing muscle mass is undesirable for aerobic activity because of the inefficiency of having to move the extra weight. Art outruns his buddies, in part, because he has developed strength proportionately over muscle mass. This is because strength does benefit endurance because it contributes to the efficiency of the running movement itself. I think it is also fair to say that jogging requires mini bursts of strength (type 2 muscle fiber recruitment) as the rear foot propels the body forward. Have you ever noticed the size of the calf (gastrocnemius) muscles on runners? One would not see those increases in size if they were only using endurance (type 1) fibers. There are other issues here though, as well, as far as increasing VO2 max and the lactic acid threshold that come from aerobic conditioning.

Posted by: Yuneek at November 22, 2006 4:35 PM

Correct me if I'm wrong but:
aerobic exercise: Uses protein as energy substrate, even from muscle mass.

Anerobic exercise: Uses less protein and builds muscle mass (increasing protein stores)

So, wouldn't a body that has be exercised primarily through anerobic means have a higher reserve for aerobic exercise (i.e. flight) than one that exercises primarily aerobically? That is to say, anerobic exercise can create a situation where you are better prepared for aerobic exercise, thus sprints help better for long runs, or Art's stories of running faster than his slow running-obsesed friends?

Is this logic right?

Posted by: Elam Bend at November 22, 2006 8:27 AM

Another interesting couple of posts today. Just one quick comment on the accuracy of part of the piece today on negatives. Art says there that "Shortening the muscle in the eccentric phase tears fibers..." In fact, you cannot shorten muscle during an eccentric contraction. An eccentric contraction, by definition, is when the muscle is being lengthened under control. As in when you are lowering the dumbell after curling it up (which is the concentric phase). Just to clarify any confusion for readers. Love the site and have visited to read daily for about a year now. Has turned my thinking upside down. Please continue!

Posted by: KMan at November 21, 2006 2:02 PM

I believe eccentric contractions occur with lengthening of the muscle; concentric with shortening.

Posted by: auntulna at November 21, 2006 11:32 AM

Very interesting, as always. One questions comes to mind though. I've taken it from your previous posts that one goal in EF is to minimize insulin production. You observe in this post, however, that anaerobic exercise, and EF exercise in general, increases insulin response to protein (a significant component to an EF diet, and which in this post you urge people to consume at rates higher than the RDA). Is this just a case of "there's no free lunch" or do you believe that this sort of insulin response is heathful?

Posted by: Anthony Candido at November 21, 2006 11:07 AM

Negatives, Protein Requirements, and Turnover

November 20, 2006 08:37 PM

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