What is the USRDA of protein?

Remember when, a long time ago, those nutrition information labels on food products got updated from a simple table to a more detailed label with a larger, snazzier font? On the old tables, protein was always at the top of the list, with a listed percentage of the RDA (Recommended Daily Allowance) – but on today’s labels, not only is it always at the bottom, it only shows how many grams of protein are present, with no % listed.

So, what’s the deal? Is there an official RDA for protein or not? Why did they change it? Is this a sign of vegetarian lobbyists infiltrating the FDA?

The amount of protein you need is dependent upon the amount of exercise you engage in. A sedentary person needs 0.8 grams of protein pwe kilogram of weight (2.2 pounds). However, if you engage in a heavy exercise schedule, you’ll need up to twice that much, depending upon how heavy.

This is one of the more controversial issues in gyms across America, as there appears no scientific consensus on (reasonable) upper limits for the highly athletic. What’s frightening are the gullible and desperate few who really do believe that more protein is always better.

I’ve met guys who load their diets with whey/soy protein supplements to reach their goals of ingesting 1.0 to 1.5 grams of protein per pound of body weight daily. For a 200-pound man, this translates into a daily intake of 200 to 300 grams; God only knows the long-term consequences of this dietary imbalance.

Most reasonable males I’ve met who are sports/workout fanatics seem to aim for somewhere in the 70 to 90 grams/day range–still quite high. Almost to a man, they sneer at the current RDAs as the stuff of 98-pound weaklings.

In addition to bodybuilders - protein needs vary not just with exercise but also with age (growing children need more per pound than an adult) and health. Illness, injury, or surgery can require increased protein for tissue repair and healing.

Folks with dysfunctional kidneys need to limit protein intake, since the kidneys process toxic byproducts of protein digestion and malfunctioning or non-functioning kidneys have a reduced capacity to cope.

So a 17 year old football player who is still growing taller is going to require much more protein per unit of body weight than a sedentary 80 year old with end stage renal disease.

That being the case - talking about a protein “RDA” is not practical. Better to list the grams of protein so those that have reason to be concerned can keep track for their own personnel needs.

Here is an interesting analysis about how the USDA came up with their .8g/kg recommendation:

“The best way out is always through.” – Robert Frost

*Originally posted by Lao Tzu *
**Here is an interesting analysis about how the USDA came up with their .8g/kg recommendation:

Lord, what sloppy methodology! Yet more proof that even government researchers have no problem cloaking their cluelessness in a veil of pseudo-science and quantitative mumbo-jumbo. I might note that a 70-kg person (approx. 155 pounds) is decidedly spindly for a man and certainly not representative of most athletes–or those who wish to be same. There’s got to be better research than this.

Depends upon how you define “athlete.” Look at those Ethiopians in the distance races. They barely weigh 100 pounds. Are they not athletes?

“Most athletes.”

The Recommended Dietary Allowances: 10th Edition was published in 1989. (Incidentally, it’s the National Academy of Sciences that sets the RDAs, not the FDA. More specifically, the RDAs came from the Subcommittee on the Tenth Edition of the RDAs, of the Food and Nutrition Board, of the Commission on Life Sciences, of the National Research Council, of the National Academy of Science.)

Anyway, according the guidelines on protein intake, the RDA for an adult males (19+) is 0.8 grams/kilogram, which using their average weight estimates is 58-63 grams per day. Adult females have the same ratio, which works out to about 46-50 grams per day. For pregnant women add 10 grams per day, and nursing women add 12-15 grams per day. The highest rate recommended is for infants during the first six months – 2.2 grams/kilogram.

And for some additional information, there is The Role of Protein and Amino Acids in Sustaining and Enhancing Performance, which was done for the U.S. military. The conclusion in the chapter on Exertion, Metabolism, and Protein Requirements is that as long as “energy balance” is maintained, the 0.8 g/kg ratio should be sufficient. I think this addresses the requirements of most athletes, though not body builders or those looking to add muscle mass. There is a chapter on Regulation of Muscle Mass: Aging and Hormones that might touch on this issues, but I don’t have time to read it (and I’m not sure I would understand it).

Athletes may require 1.2 - 1.6 grams of protein per kg of weight according to this .

Why was the methodology so sloppy? The researchers measured how much protein a population sample needed, e.g. the minimum value. For a reasonable sample size, this will likely produce a bell curve. Take 5 sample deviations and you have 98% of the sample population.

But the real population may differ from the sample population. And requirements are minimum requirements. What are the conseqences of coming up with a number lower than the minimum requirement in published recommendations? More people would falsely think they were getting adequate protein. A 30% increase makes this unlikely and has no obvious health risks. Would things be better if elevators collaped with 1200 lbs of passengers? Do you really need 2L (eight cups) of water to keep hydrated – your kidneys only need half that… but when a higher number is safer, why not quote a higher number?

As for too much protein, this could cause gout, kidney damage, uremia and hepatic encephalopathy. The needs of high school bodybuilders may not be as high as athletes who train six hours a day.

First, consider the reference 70-kg. person. Fine for most (non-athletic) women, not so fine for many, many men, athletic or no. For better or worse, people are getting larger/heavier each generation, so why establish a spindly 70-kilo standard befitting John Adams’ era? (I think this standard comes close to the current median weight of adult females.) Next, lacking confidence in their methodology, USDA boosts their minimum figure by 30 percent, then boosts it yet again just so they can speak authoritatively. What science drives this action? Third, athletic individuals are given no meaningful guidelines and appear essentially ignored, unless one assumes this group lies outside the five standard deviations, an unlikely assertion. Yes, USDA claims athletic people are accounted for. In what way? Which sports? What was the sample comprised of? How many sedentary or elderly persons were grouped in it? Are we to assume that a very active 22-year-old has the same nutritive needs as a sedentary 63-year-old watching Wheel of Fortune marathons? This one-size-fits-all thinking offers little guidance to many of us.

I’m not sure I entirely agree.

i) 70 kg is a pretty standard reference in physiology textbooks and is often used, wrongly or no, as a basis in many medical calculations. This number may seem small to you, but it isn’t tremendously unreasonable even today. If they determined the minimum protein for a large sample, it would be easy to calculate the amount per pound weight and it appears these figures are indeed available. If people are getting fatter, it is the interests of their health to consume fewer calories and this includes less protein and I don’t think using an ideal weight as the basis is way way off base.

ii) An increase of 30% and a titch is indeed arbitrary. Perhaps a little less arbitrary than the article implied. A recommendation along the lines of “we recommend you scrape by with the barest minimum amount of protein” could be dangerous advice. Adding thirty percent makes it less so. Engineers often use an arbitrary safety factor in design. Nutrition as a whole is far less precise than you think it is, and the danger is not guessing too high but too low.

iii) A sample population would include some athletes. If this does not include specific advice for weightlifters, tough. This is the realm of sports medicine research. The USDA recommendations are meant to apply to average individuals, children, pregnant women. It is not meant to fit all, nor should the USDA fund this research in every special population. Athletes who eat the USDA amounts of protein may or may not get an optimum result, but they will be healthy and have no problems with protein deficiency either. The USDA should be concerned with basic health needs and not gold medals.

Remember that the USRDA, at least that listed on most food containers, is scaled for a 2000 Calorie per day diet. They tell you, if you require more than 2000 Cal/day, then you’ll need to compensate. I think they were just being consistent.