Category Archives: Exercise - Page 2

Protein for Athletes

How much protein should athletes consume?

Bodybuilders have long known that consuming extra protein makes it easier to add muscle. Yet low protein dieting can enhance immunity against viruses and bacteria, and extends lifespan in animals.

The Perfect Health Diet, because we’re positive toward saturated fats and starches, will often lead to lower protein consumption than other Paleo diets that restrict fatty or starchy foods. So it’s natural that some athletes and bodybuilders have asked how to optimize protein intake.

Robert recently asked about this, but let’s look specifically at the case of Advocatus Avocado:

I believe my performance improved (albeit marginally–the differences aren’t large) when I allowed my protein/carb/fat ratios to remain consistent despite my high caloric intake, which is ~3,600 calories/day. In other words, I had a sense of better performance when I lowered my fat% to around 65 and allowed around 200g/day of protein (I work out 2-3x a week for an hour).

At 3,600 calories per day, 65% fat is 2340 calories; 200 g protein is 800 calories; that leaves 460 calories carbs. How do these compare with Perfect Health Diet recommendations for athletes?

Nitrogen Balance, Exhaustion of Benefits, and Toxicity

There are a few magic numbers for protein intake that we want to be aware of:

  • Nitrogen balance. Nitrogen comes into the body in dietary protein and leaves the body in urine as ammonia, urea, and uric acid after proteins are metabolized. So when a person is in nitrogen balance, the amount of dietary protein matches the amount of metabolized protein, and the protein content of the body is unchanged. Very likely, the muscle content is unchanged too.
  • Exhaustion of benefits. We want to find the “plateau region” for nutrients. Athletes want to know: at what level of protein intake does protein no longer help build muscle?
  • Toxicity. At what level of protein intake does protein begin to damage health?

Luckily Ned Kock of the superb Health Correlator blog has done much of the work for us in his post “How much protein does one need to be in nitrogen balance?.”

He presents this chart, from a book on Exercise Physiology [1]:

There’s a great deal of variability across persons. Some people are in nitrogen balance at protein intake of 0.9 g/kg/day; others need as much as 1.5 g/kg/day. At 1.2 g/kg/day, half the sample was in nitrogen balance.

Various factors influence the interpretation of this data:

  • The sample was of endurance athletes. Endurance exercise increases protein needs, so most people would reach nitrogen balance at lower protein intakes. Resistance exercise doesn’t require as much protein: Experienced bodybuilders are typically in nitrogen balance at 1.2 g/kg/day. [2]
  • Most of the sample probably ate a high-carb diet. Glucose needs were met from dietary carbohydrates. Low-carb dieters would need additional protein for glucose manufacture.
  • As Ned states, in caloric deficit, protein needs are increased; in caloric surplus, protein needs are decreased. If you’re restricting calories for weight loss, expect to need a bit more protein to avoid muscle loss.
  • Supplementing leucine “increased protein synthesis and decreased protein breakdown” [2], thus leading to nitrogen balance at lower protein intakes.
  • The point of nitrogen balance is dynamic: if everyone in the sample ate 0.9 g/kg/day, then they’d eventually get into nitrogen balance at 0.9 g/kg/day. The body adjusts to conserve muscle at given food availability.

The average person needs much less protein to be in nitrogen balance. The US RDA for protein, 0.8 g/kg/day, was set so that 97.5% of Americans would be in nitrogen balance. [2] But just to be conservative, and because we’re developing advice for athletes, let’s consider 1.5 g/kg/day as the protein intake that brings our athletes into nitrogen balance.

What about the protein intake that exhausts benefits?  At what intake is muscle synthesis no longer promoted?

Ned, citing a review paper [2], offers the following answer: “[P]rotein intake beyond 25 percent of what is necessary to achieve a nitrogen balance of zero would have no effect on muscle gain.”

On my reading it’s not so easy to infer a clear answer, but let’s go with this. If so, then muscle gains would be exhausted at 1.25*1.5 = 1.875 g/kg/day even for the most strenuous athletes.

What about toxicity?

We deal with this in our book (p 25). At a protein intake of 230 g/day (920 calories), the body’s ability to convert ammonia to urea is saturated. [3] This means the nitrogen from every additional gram of protein lingers in the body as ammonia, a toxin.

Clearly marginal dietary protein is toxic, via ammonia poisoning, at this intake level. A reasonable estimate for where toxicity begins is between 150 to 200 g/day.

Putting it together: A prescription for athletes

Let’s say our athlete is an 80 kg man. Then maximum muscle gain will be achieved at a protein intake of 1.875*80 = 150 g/day. Toxicity will begin somewhere between 150 to 200 g/day. So the “plateau region” where all the benefits, and none of the toxicity, are achieved is between 150 g/day and some protein intake not much above 150 g/day.

The plateau region is quite narrow! What this tells us is that athletes should consume about 150 g/day protein.

This assumes a high-carb diet, so that no protein is needed for gluconeogenesis. The body utilizes about 600 calories/day of glucose, plus another 100 calories per hour of intense training.

With carb intakes below 600 calories/day, additional dietary protein would be needed, because protein would be consumed nearly 1-for-1 with the missing carbs.

So we can summarize these results as follows:

  • On a high-carb diet (>600 calories/day), 600 protein calories/day maximizes muscle gain.
  • On a low-carb diet (<600 calories/day), 1200 carb+protein calories/day maximizes muscle gain.

Looking back at Advocatus Avocado’s personal experience, he eats a low-carb diet with 460 carb calories per day. We predict therefore that he would need 740 protein calories a day to maximize his muscle gain (plus up to another 100 calories per hour of training, to replace lost glycogen).

Advocatus says he needs 800 protein calories/day to maximize muscle gain. Close enough for blog work!

At these protein intake levels, Advocatus is probably experiencing mild ammonia toxicity. He might slightly improve his health by eating a few more carbs, and cutting his protein intake a bit.

He might also find that leucine supplementation would reduce his protein needs a bit.

Overall, however, I think his experiences are consistent with our framework for understanding nutritional needs. Those who are content with maintaining an ordinary person’s muscle mass can get by with relatively low protein intakes of 0.8 g/kg/day or less. But muscle-building athletes need high protein intakes, around 1.9 g/kg/day, to maximize the rate of muscle gain. If they eat low-carb, they may need even more protein. Such high protein intakes are likely to exceed the threshold of toxicity.


[1] Brooks, G.A., Fahey, T.D., & Baldwin, K.M. (2005). Exercise physiology: Human bioenergetics and its applications. Boston, MA: McGraw-Hill.

[2] Wilson, J., & Wilson, G.J. (2006). Contemporary issues in protein requirements and consumption for resistance trained athletes. Journal of the International Society of Sports Nutrition, 3(1), 7-27.

[3] Rudman D et al. Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects. J Clin Invest. 1973 Sep;52(9):2241-9.

Art de Vany’s New Book and Video

Art de Vany’s long-awaited book, The New Evolution Diet, has finally been released.

For those who don’t know him, Art is an economist, former professional (minor league) baseball player, and early adopter of low-carb Paleo dieting, which he used to help address the diabetes of his first wife and son. He is also a fitness guru, and had one of the first popular Paleo sites. Now 73, he looks fantastic.

I discovered Art in 2005, thanks to a link from Newmark’s Door. At the time I had a chronic illness that had progressed steadily for 13 years and was becoming disabling. I had experimented that year with Chinese herbal medicines and found some dramatic effects, good and bad. This experience had persuaded me that what I ingested could have big effects on my health. I began to try to optimize my diet, and Art persuaded me to give low-carb Paleo a try.

Like the Chinese medicine, Art’s diet (or my implementation of it) had big effects, both good and bad. Our experience with it set my wife and I off on a search for the perfect diet for human health, and resulted 5 years later in our own book.

In the end, my health was repaired, but effecting a cure required significant refinements to the Cordain – de Vany style Paleo diet.  

I owe Art a great debt: without his work I would never have recovered my health. I’m pleased, therefore, to be able to link to his new book, which I intend to read soon. On his web site and DVD, Art has always had many excellent and interesting things to say, especially about fitness and lifestyle. I’ve implemented his “hierarchical sets” method of training in my own exercise routines; and he was the one who got me started on intermittent fasting. His idea that intermittency and variability are needed for optimal health is a seminal contribution which could prove important.

Melissa McEwen has a review with some quotes. Unfortunately, it seems that all of the major weaknesses of the diet which caused trouble for me 5 years ago are still present. Art advises, in my view, insufficient intake of two of the principal calorie sources of actual Paleolithic diets:

  • Safe starches. Starches have been a leading calorie source in the ancestral human diet for two million years; Richard Wrangham credits them with making us human. Yet Art restricts plant foods to vegetables and fruit – as if our ancestors were forest dwellers, like mountain gorillas and chimps, instead of the open woodland and shoreland dwellers they were.
  • Fat, especially saturated and monounsaturated animal fats. Cracked bones and skulls at Paleolithic sites testify to the hunger of our ancestors for marrow and brain. Yet Art advises eating lean muscle tissue.

Perhaps influenced by the lipid hypothesis, Art seems as positive toward industrial canola oil as toward animal fats and egg yolks.

Regarding the diet, I share Melissa’s feelings. It is a good, but flawed, diet. Our book is a much better source of diet advice. Yet I’m sure there will be much that can be learned from Art’s book.

I will always be grateful to Art for introducing me to Paleo eating. I encourage everyone to view Art’s promotional video; it’s a very impressive introduction to a remarkable man.