In this series to date I’ve been talking about the needs of strength training athletes in regard to protein and so far have shown that at most a modest amount of protein is enough to build bigger and stronger muscles. Is it possible that too much protein can actually be a bad thing? I’m not talking about the kidney problems or bone loss that so many physicians have warned will happen with high protein diets, as there has never been a documented case of protein causing kidney issues in regular, healthy individuals and the bone loss warnings seem to be overstated as well. If that’s the case then what’s the big deal about a high protein diet?
The biggest issue with high protein diets is that many nutrients must be removed from what was a balanced and healthy diet in order to have high protein consumption without increasing overall energy intake. The most often-victimized macronutrient is the carbohydrate. Carbohydrates are required to fuel performance, which is especially true of endurance training, but it as also true of high intensity resistance training. This means lifting weights effectively enough to stimulate hypertrophy will only occur if properly fueled. Touching on the endurance training for a second – does any good workout ever NOT feel like a test of endurance? Obviously, as your workout progresses your strength will falter if you are not adequately fuelled as well. This means that dieting or not, you can’t maintain or grow your muscles without the carbs it takes to be at your strongest.
Put another way, energy intake is the most important nutritional factor for increasing muscle mass. You all know that you need above your maintenance calories in order to grow. Similarly, it is impossible to maintain a positive nitrogen balance when in a caloric deficit, even when protein intake is high(1).
On the other hand as long as the energy balance is in the positive then many different protein intakes will yield newly built muscle tissue. If we want to look at a very old example, it was shown that soldiers will build muscle at fairly low levels of protein intake, meaning one gram per kilogram of body weight per day or less than half a gram of protein per pound of body weight a day(2). That’s really not very much by our modern measuring stick.
A much more recent study showed that increased muscle mass during resistance training was equivalent when athletes were fed 2,000 extra calories on top of their normal dietary intake in the form of either carbohydrate alone or carbohydrate plus protein(3). Both of these studies suggest that as long as protein is adequate, meaning as little as .45 grams per pound of body weight, then it is energy that is required to do the growing of the muscle. Although I’m interpreting those studies, what they show is that the body will repair its muscle with very little protein but in order to grow it will require a lot of carbohydrate. Of course energy can be supplied with any macro but you get my point.
One thing that all of us who train regularly do without even realizing it is consume more calories than we would if we didn’t get to the gym several days every week as this type of training requires more fuel(4). This means that by our increase in calories we will already be consuming more protein and that means we don’t need to try as hard as we think to make sure we’re getting enough. If we are hitting the minimum requirements for protein which can be as little as 10-15 percent of our total calories, we will grow muscle based on a positive nitrogen balance.
The body appears to respond to nutrition uniquely to each training session and this makes it difficult to determine a general amount of protein to apply to everyone. Timing of protein intake as well as protein quality and the type of other nutrients ingested will all have an impact on the result. This is why following someone else’s diet never seems to get you the same result as it got them.
The type of protein ingested appears to influence the anabolic response as well. Research shows that milk will stimulate muscle anabolism following exercise more so than will soy protein(5). It is possible that animal proteins elicit a superior anabolic response although I’m not sold on that theory at all. It is just as possible that milk is a food and soy protein is a supplement and as such the body responds better to milk as it’s a whole food rather than a supplement.
If you’re buying in up to this point then you realize that energy intake is more important than protein intake when it comes to muscle hypertrophy. Protein is of course essential for muscle growth but it is the energy that will be responsible for providing the fuel needed to grow. Next up I’d like to look at amino acids and protein timing. Until then,
1.J Nutr 1984; 114(11):2107-2118
2. Chittenden RH: The Nutrition of Man. London, Heinemann, 1907.
3. J Sports Med Phys Fitness 2002; 42(3):340-347
4. J Appl Physiol 1992; 72(4):1512-1521
5. Am J Clin Nutr 2007; 85(4):1031-1040
This article was written and researched by Matt Taylor
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