T Nation

Maximal Urea Sythethis Rate

I just finished an exhaustive article on hunter-gatherer diets, and I ran across something pretty interesting. It seems that Amerindians and early American settlers were familiar with a disease they called “rabbit starvation.” The researchers who wrote this article figured that the symptoms of this wasting disease were indicative of excess protein consumption (rabbits are only about 2% fat), and used their data and that of others to create a formula (range: 55–76 mg N•h-1•kg body wt-0.75) that predicts the maximal amount of protein a person can ingest before problems (hyperammonemia and hyperaminoacidemia) occur. Since the formula allows for deviation, an 80kg person would be OK consuming protein in the range of between 212 and 292 grams per day, with the average being 250g/d. I’ve been consuming about 370g/d at 180lbs for about 3 months and haven’t noticed any problems. Many feel that protein consumption in excess of 1.3g/lb of body weight is a waste of money, and now I’m leaning toward this camp of thought. Cutting down protein and upping good fat will certainly make my grocery bill easier to bear. Check out the full article at: www.ajcn.org/cgi/content/full/71/3/682.

Interesting article but I can’t agree
with all of your conclusions.

It’s sort of like finding an article where
someone claimed that, for example, performing
more than 8 sets per week led to overtraining and illness.

They may have published it. They may have believed it heart and soul. But looking around you, you can see they were in error.

Or for a more notorious example, someone may have published that anabolic steroids do not improve muscle mass or athletic performance.

Or that Nubain is non-addicting or has very low addictive potential. Sure, the scientists who wrote that, based on animal studies, no doubt believe it.

But in cases like this, where tons of evidence right in front of you contradicts some rather tunnel-visioned statement in an article, one should just consider the broader view rather than necessarily believing these probably-sincere but wrong claims.

An important point in the article was the
the problems in protein metabolism occurred
in the ABSENCE of fats or carbs. In athletic nutrition, we’ve known for a long time that protein-only is a horrible way to go: one must include carbs or fats, in amounts at least approximately equal to protein.

The “rabbit starvation” you and the article mention is in reference to diets with essentially no carbs or fats, only protein.
The article states, “Clinical documentation of this syndrome is virtually nonexistent,
except for a single case study.”

So this can hardly be broadly applied to bodybuilding or athletic nutrition.

And for all we know, the cited reference
that came to the conclusion on rate
of urea formation may have been derived
under conditions quite unlike athletic
use. I’d certainly read the article that
derived the equation before coming to
the first conclusion about the equation.
For example, suppose it was derived
from studying protein-only diets? Then
it would have no application.

However, I agree with your conclusion
that under natural training conditions,
most of the time, your 370 g/day was
a waste of money, and something around
250 g/day would probably do as well for
you in terms of muscular gains.

“Rabbit starvation” happens when you eat protein and nothing else. The thermic effect of protein is so strong that it actually takes more energy to digest the protein than the protein provides. This disease was relatively common in neanderthals and early humans.
The application of this type of diet is probably not a good idea. If you were to do this type of diet (only protein) for a VERY short time (2 weeks or so) I think you would be safe and could possibly see a significant decrease in fat without losing much muscle (depending on how many calories you are taking in).
Still, I wouldn’t suggest anyone try this type of diet, but if you are going to give it a go I would recommend that you go to your doctor and make sure your kidney function is optimal before you attempt it.

One question, how have the Eskimos and Inuits managed to stay so heathy all these centuries while subsiding on absolutely nothing but animal flesh (strictly high protein diet)? Studies have shown that heart disease and diabetes were unheard of in these cultures until they migrated into western communities and started to subsist on the traditional western diet. This artical sounds like another biased hyped protein scare. How come with all the athletes eating a high protein diet over the last 50 years, no protein diseases have been reported? Although I admit not bothering to read the artical, I am curious if the supposed “rabbit starvation disease” occured only with the consumption of rabbit as wild rabbits are notorious for playing host for a varity of organisms and associated diseases and that in my mind would more likely be the cause of health related problems. In the case with rabbits only causing the disease, why did not other animal consumption also not cause it as Indians and early settlers surely ate other animals besides just rabbit. Sounds like biased and bad science to me. As most other athletes, i’d rather error on the side of overconsumption when it comes to protein and besides, excess protein calories do not convert to fat as easily and directly as carbs or fats due to thermogenic effect of breakdown and conversion. Sounds like the biased preconceived “study” of a “scientist” with an agenda.

I expect Eskimos get a good deal of fat
in their diet as well, though I don’t
have definite information.

As for protein-only for brief periods
of time like one or two weeks, I tried
it myself once and considered it a failure,
at least for myself. Much better, for same
calories, to reduce protein to no more
than 50% of calories.

You’re right eskimos can eat all that protein because they’re also consuming a lot of fat along with the protein. If I remember correctly from what I’ve read rabbit starvation only occurs when one is consuming extremely lean protein (90%+lean) sources such as rabbit, venison, etc.

It’s due to the fact that rabbit meat is very lean. The lack of fat in the diet causes the problem, not the amount of protein consumed. Native Americans used to eat nuts to provide fat in their diets for this very reason. Many times scientists will jump to a conclusion based on what they want to see rather than what is actually true.

In 2001 at the American College of Nutrition annual conference Dr Peter Garlick discussed “rabbit starvation:” and limits on protein metabolism, but basically said the same things that Bill Roberts said herein. Do a medline search on Pete, he knows his stuff, is pretty entertaining and a legiot scientist at Stonybrook in NY

A lot of references about rabbit starvation used in that article are also annecdotal, as well as seeming very similar to food poisoning, which is highly likely considering the environment.

Eskimos diets were ~90% animal, wiht ~10% from plants (generally when available)

In the 80s there was a paper in the ajcn that compared eskimos to danish diets, the eskimos had lower heart disease risks, but also a lower fat intake (but drastically different sources). They (in this study) ate ~40odd% fat.