If you ask a room full of bodybuilders if there is any controversy about the importance of high-protein intake for muscle and strength gains, they will unanimously say, “Nope, more is better.” But can we really trust bodybuilders? They take just about everything to the extreme and protein is no exception. Interestingly, if we take that same question and ask a room full of academics you will undoubtedly get a 70/30 split with most saying that athletes, including weightlifters, will gain no benefit from eating a high-protein diet. Yet the minority that condones this type of diet seem every bit as confident as the naysayers. So why is this? It’s because the results from research on protein intake and strength training are all over the map. Interestingly, the majority of studies looking specifically at the impact of additional protein intake on resistance exercise outcomes show a significant positive effect. Nevertheless, to date there is still no consensus about the benefits of higher protein intakes for muscle mass and strength gains. This discrepancy in results from protein intake studies is precisely what a recent paper published in the Journal of the International Society of Sports Nutrition tried to settle, or at least explain.
The paper offers two theories for why studies on protein intake and gains in mass and strength with weight training do not always agree. The authors have named the two theories “sufficient spread” and “protein change.” Protein spread theory states that there must be a sufficient difference in the amount of protein intake between experimental groups to see muscle and strength differences. Many studies try to compare differences as small as 9% in grams of protein per day between groups. The authors postulate, and demonstrate with this latest paper that in fact, those studies that fail to show benefits from increased protein are comparing groups that differ very little in actual protein intake. So comparing the two is unlikely to show a significant difference.
The protein change theory states that in order to see an impact of increas ing protein intake, you have to increase beyond what the subject habitually eats. The average change in habitual protein intake in studies showing higher protein to be more effective was 60% versus 7% when additional protein was no more effective than control. The authors remind us that just because you are eating a relatively high-protein intake already, it may not be offering you the same benefits as actually increasing protein intake does. Your body will adapt and adjust to the amount of protein you eat each day by disposing of more each night, otherwise you literally would continue to grow and grow from diet alone. So, you are going to have to increase your protein intake by perhaps 50%. If you have been eating 1 gram per pound of bodyweight per day, consider slowly tapering down by 50 grams or so. Then, when you are ready to blast for a bit, up your protein abruptly and see if you can’t put some of that protein toward new gains.
