Using egg protein, one study showed that muscle protein synthesis reached a plateau when 20 grams of protein was consumed. When 40 grams was consumed, there was no further increase in muscle protein synthesis.
A similar study was conducted with whey protein isolate. Study participants consumed whey after a session of single leg knee extensions, using the non-exercised leg as a control.
After exercising one leg, they consumed a drink containing 0, 10, 20 or 40 grams of whey protein isolate. Measures of muscle protein synthesis were taken for 4 hours after exercise in the control (non-exercised) leg (to determine the effects of simply ingesting whey without exercise), and in the exercised leg (to determine the effects of whey plus resistance exercise). Muscle protein synthesis was higher in the exercised leg compared to the control leg at all doses of whey, consistent with the complimentary effect of whey and exercise.
In the non-exercised leg, there was a significant increase in muscle protein synthesis with the 20 gram dose, but no further increase with 40 grams. In the exercised leg, there was a significant increase in muscle protein synthesis with 20 grams of whey, and a further 32% increase with the 40 gram dose.
Dominick Walsh is a blogger for Performance Nutrition and TMRzoo.com and covers all men’s health topics and exercise issues including protein powders, diets, weight loss, weight lifting supplements, fat burners and supplement reviews. Dominick’s columns cover everything you need to know about your pre, during and post workout nutrition.