How often have you heard that you need 1g of protein/lb of body weight? It sounds logical right, I mean when you're working out you need to increase your protein intake and a gram is a nice round number... What if I were to tell you that it's a bunch of hokum? What if I were to tell you that you can get the same benefits with much less protein intake? And, What if I were to tell you that you're wasting your money on protein supplements? I'm suspecting that some of you will not like me very much.
Here's the actual truth.
Firstly, protein is essential for hypertrophy (muscle growth).
In order for muscles to grow protein synthesis has to be greater than protein breakdown
Resistance training stimulates breakdown of muscle protein and increase of muscle protein synthesis
Breakdown of muscle protein happens quicker than synthesis following resistance training and proteins will need to replaced through diet
Protein synthesis will plateau even with increased intake at a certain point. This means that no matter how much protein you take in, there will be a point where synthesis will no longer need the added protein and what's left over more-or-less becomes urea.
So yes, you will need more protein when you are exercising, but how much exactly? Here's what the literature says:
Well, first the Recommended Dietary Allowance (RDA) of protein is 0.8g/kg (0.36g/lb) for the general population. It has been suggested in laboratory studies that athletes required up to double the RDA, roughly 1.6g/kg-1.8g/kg (0.72g/lb - 0.81g/lb). This is still far less the the amount commonly recommended by fitness professionals of 1g/lb, so let's dig a little deeper.
Lemon (1991) suggests that endurance athletes require up to 1.4g/kg (0.63g/lb) and strength training athletes require up to 1.8g/kg (0.81g/lb); what about the bodybuilders or people who have been lifting for years, surely they require even higher protein intake than that. Not according to Phillips et al. (1999). They found that for trained lifters - those who had be lifting for at least 5 years with at least 3 sessions per week - had a reduced rate of protein breakdown following exercise than untrained lifters, suggesting that they would require less protein than their novice counterparts. More to that point, Lemon et al. (1992) found that experienced lifters required only 1.04g/kg (0.47g/lb) compared to 1.5g/kg (0.67g/lb) for novice lifters.
A more recent study by Hoffman et al. in 2006 confirm the findings of earlier studies. They found that collegiate athletes did not benefit from higher protein intakes of >2.0g/kg (0.90g/lb) compared to recommended levels fot athletes of 1.8g/kg (0.81g/lb).
Now, there are other issues that effect hypertrophy with relation to protein intake such as the timing of when protein is consumed, the quality of the protein, overall calorie intake and where these calories come from (fats or carbs), and the type of sport involvement. However, I've yet to read a study that supports a total protein intake greater than 1.8g/kg (0.81g/lb). I'd be happy to read any study that supports a greater intake if any someone can find me one.
Now, I'm not saying that protein supplements are an entirely bad thing. There are days when reaching the RDA may be difficult or certain groups of people (such as those with celiacs) may find it difficult to reach the amount through diet alone. In these cases I can support the use of protein supplements. I just want you guys to understand that protein requirements are much lower than the industry may have you believe, and the widely perpetrated myth that 1g/lb is needed has no scientific basis. I will concede that it is a nice round number, so it makes the math easy. It is, however, more than double what most people actually require.
Bohé, J. et al. (2003). Human muscle protein synthesis is modulated by extracellular, not intramuscular amino acid availability: a dose-response study, J Physiol, 552 (1), 315-324
Hoffman, J. et al. (2006). Effect of Protein Intake on Strength, Body Composition and Endocrine Changes in Strength/Power Athletes, Journal of the International Society of Sports Nutrition, 3 (2), 12-18
Lemon, P. (1991). Effect of exercise on protein requirements, Journal of Sports Sciences, 9, 53-70.
Lemon, P. et al. (1992). Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. J Appl Physiol, 73, 767– 775.
Phillips, S. et al. (1999). Resistance training reduces the acute exercise-induced increase in muscle protein turnover, Am J Physiol Endocrinol Metab, 276, E118-E124.
Tipton, K. and Wolfe, R. (2007). Protein and amino acids for athletes, Journal of Sports Sciences, 22 (1), 65-79.