Sunday, July 26, 2009

Protein Requirements

10:28 AM by dody ·
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As most people who lift weights are well aware, the “one gram of protein per pound of body weight” rule has been the mainstay advice for protein intakes for decades. But is it correct? In the past, mainstream nutritionists and medical doctors have warned of dire consequences from such intakes of protein, which we now know is total bunk.

They also maintained for decades that athletes didn’t need additional pro-
tein above the RDA.

For the past half-century or so, scientists - using crude methods and poor
study design with sedentary people - have held rm to the belief that
bodybuilders, strength athletes of various types, runners, and other highly
active people did not require any more protein than Mr. Potato Head ...err,
I mean the average couch potato.

However, in the past few decades, researchers using better study designs
and methods with actual athletes, have come to a di erent conclusion al-
together - a conclusion hard-training bodybuilders have known for years.
The fact is that active people should consume far more protein than the
RDA to maintain hard-earned muscle tissue when dieting, and to increase
muscle tissue during the o -season.

As one of the top researchers in the eld, Dr. Peter Lemon, stated:

“These data suggest that the RDA for those engaged in regular endurance ex-
ercise should be about 1.2 - 1.4 grams of protein/kilogram of body mass (150%
- 175% of the current RDA) and 1.7 - 1.8 grams of protein/kilogram of body
mass per day (212% - 225% of the current RDA) for strength exercisers.”

Another group of researchers in the eld of protein metabolism found that
strength-training athletes eating 0.86 grams per kilogram of body weight
(close to the RDA for protein) showed a decreased whole body protein syn-
thesis (that’s losing muscle, jack!). They came to an almost identical conclu-
sion to that of Dr. Lemon in recommending at least 1.76 g per kilogram of
bodyweight per day for strength-training athletes to stay in positive nitro
gen balance/increases in whole body protein synthesis
This same group found in later research that endurance athletes also need
far more protein than the RDA/RNI and that men catabolize (break down)
more protein than women during endurance exercise. They concluded:

"In summary, protein requirements for athletes performing strength training
are greater than sedentary individuals and are above the current Canadian
and US recommended daily protein intake requirements for young healthy
males."

It should be noted that there is still some confusion on this point. In fact,
some prominent researchers have suggested that protein metabolism ac-
tually becomes more e cient with training, and that there is no evidence
of increased protein needs for either strength or endurance athletes. How
do we resolve this con ict?

First of all, we need to acknowledge a critical fact: there is a di erence be-
tween what's needed to maintain lean body mass, and what's optimal for
increasing it. As a recent review on the subject acknowledged:

"...for athletes desiring muscle hypertrophy, there is little reason to limit protein
intake and relatively high intakes might be the best recommendation...Even if
2.5 - 3.0 g protein * kg-1 BW *day-1 is consumed and this amount of protein is
more than the synthetic machinery can process, the excess will simply be oxi-
dized. As long as the intake of other nutrients important to the success of an
athlete is not compromised, there appears to be little harm in ingesting these
high amounts."

How does this information relate to the eating habits of the average ath-
lete following the one gram per pound of body weight rule? Well let's see.
Given that scientists work in kilograms we have to do some converting.

Recall that a kilogram weighs 2.2 lb. So, 200 divided by 2.2 gives us 90.9.
Multiply that times 1.8 (the high end of Dr. Lemon's research) and you get
163.6 grams of protein per day.

Now this is an average gure, that doesn't take biochemical individuality
into account. As with vitamins and other nutrients, you identify what looks
to be the precise amount of the compound needed for the e ect you want
(in this case positive nitrogen balance, increased protein synthesis, etc).
Then add a margin of safety to account for the biochemical individuality
of di erent people, remembering the fact that there are low grade protein
sources the person might be eating and other variables. Since there’s no
evidence of harm, it’s best to err on the high side of the range, rather than
the low.

So the current recommendation by the majority of bodybuilders, writers,
coaches and others, of one gram per pound of body weight, does a good
job in taking into account the current research and adding a margin of
safety. In my view, one thing is for sure: a little too much protein is far less
detrimental to the athlete’s goal of increasing muscle mass than too little
protein.

The truth of the matter, of course, is that many strength training athletes
exceed the one gram per pound of body weight rule and are often closer
to 1.5 to 2 grams of protein per lb. of body weight.

There are no particular reasons why readers can’t eat intakes higher than
one gram per lb. of body weight, if they so desire, but we will stick to the
one gram per lb. gure for this chapter. This makes it relatively simple to
determine total protein intake. An example calculation is shown below.


Example:

It’s simple to determine the protein intake for a 200 lb. person:

Total protein: 200 lb. x 1 g /lb. = 200 g
Total calories from protein: 200 g x 4 calories/g = 800 calories
Percentage of cals. from protein: 800 kcal/3640 kcal = 0.22 (22%)

If the person was eating 1.5 to 2 grams of protein per LB of BW as some
do, that percentage gure would be higher. The same person eating
1.5 g of protein per pound of BW would be getting:

Total protein: 200 lb. x 1.5 g/lb. = 300 g
Total calories from protein: 300 g x 4 calories/g = 1200 calories
Percentage of cals. from protein: 1200 kcal/3640 kcal = 0.33 (33%)
On the ip side, there is some evidence that suggests an upper limit, be-
yond which additional protein is useless. There appears to be a dose-re-
sponse relationship between ingestion of essential amino acids and mus-
cle protein synthesis, but only to a point. Protein synthesis in response to
the ingestion of 6 g of essential amino acids was nearly twice that of 6 g of
mixture containing only 3 g of EAAs; but the response was similar after the
ingestion of either 20 g or 40 g or EAA.

The bottom line is that high protein intakes are bene cial, but there’s no
reason to go overboard! There is no evidence that going over 2 g protein
per lb. will be useful for most athletes wishing to build muscle.
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