It’s well established that consuming protein after weightlifting helps repair and build muscle. But how much do you need in order to maximize muscle-protein synthesis? Experts have long believed that body weight dictates intake, but that anything above 25 grams of protein is moot. Not so fast.
A new study turns that whole more-brawn-more-protein thinking on its head. Exercise scientists from Stirling University in Scotland have determined that ideal post-exercise intake isn’t as much about body weight as the type and intensity of strength training. Also contrary to previous thinking, after certain resistance exercise sessions, 40 grams of protein is indeed more effective than 20 grams at stimulating muscle protein synthesis.
To determine this, the researchers recruited 30 resistance-trained men. They assigned those who weighed 143 pounds or less to the lower lean body mass group, and guys weighing 154 pounds or more to the higher lean body mass group. Both sets of men completed two sessions of whole-body resistance training in random order. After one, they were given 20 grams of whey protein; after the other, they got 40 grams. Next, the researchers took tissue samples to assess muscle-protein synthesis following each workout.