Wednesday, 16 Jul 2008
How Much Protein Should You Be Taking?
As an athlete and semi-experienced “body-builder” I’ve been taking protein for years (since 1997). In that time I’ve heard a lot of different suggestions for how much protein one should take when actively lifting weights. Most of my influences have come from the “muscle-head” camp where more protein = more muscle.
However as I grow older and more curious about what we accept as fact, I’ve begun to rethinking the age-old question, “How much protein should I be taking?”
The following sources all suggest that the RDA (recommended daily allowance) of protein is more than sufficient for 97% of Americans. Furthermore they propose that most Americans eat approximately 1.2-1.5x the RDA. The RDA is calculated by 0.8 g/kg body weight. That is you should eat 0.8 grams of protein per kilogram of bodyweight. For my 68.6 kg body my RDA of protein is 55 grams. These sources mostly suggest that the more exercise you get, the more protein you will need. That said, the sources differ on the type of exercise that cause an increase in protein need. For example, weighttraining.about.com proposes that only endurance sports create a physical demand for more protein and that normal weightlifting does not require increased protein intake.
All three sources below recommend NOT taking protein in excess of 2.0 g/kg body weight. For me, that would be not exceeding 140 g.
Since I do still occassionally perform the long swim, bike, or run, I have prescribed myself a 100 grams of protein a day, which is just under 1.5 g/kg body weight. This shoudl be more than adequate for my body to perform optimal protein synthesis.
Personally, while I agree that there are no short-term side-effects for active and healthy people overdosing on protein, I would err on the side of caution for taking too much protein over time. Excess protein must be processed by your kidneys and taking too much protein over prolonged periods of time puts unnecessary stress on your kidneys (possibly causing early kidney failure). In the example of my dog that suffered end-stage renal failure, we had to minimize protein in his diet because the proteins would make him nauseous and throw up. This was because his kidneys were no longer able to process the proteins in his blood and therefore the proteins would act as toxins.
For my purposes, I’m going to limit my protein intake from 80-100 g daily (approximately 1.2-1.5 g/kg body weight) and not to exceed 130 g daily.
Sources:
http://www.thedoctorwillseeyounow.com/articles/nutrition/protein_2/
http://exercise.about.com/cs/nutrition/a/protein.htm
http://weighttraining.about.com/od/nutritionforweights/qt/protein_howmuch.htm
