Optimal Post-Workout Dose of Protein May be 20 Grams

The optimal dose of whey protein that exercisers and strength athletes can use after training may be 20 g, according to sports scientists at the University of Stirling in Scotland as reported in the American Journal of Clinical Nutrition. The subjects that the researchers used were in their early twenties. So the findings may not apply to older strength athletes. The researchers discovered that, at least in young men, 20grams of whey protein after a weight training session provides the optimal stimulus for muscle building.

The researchers first got their 48 subjects to train their legs, doing 8 sets of 10 reps on the leg press, with 80 percent of the weight with which the subjects could just manage 1 rep. Ten minutes later the subjects were given 0, 10, 20 or 40 grams of whey protein.

The rate at which muscle fibers were synthesized did not increase by a statistically significant amount after taking 10 grams of whey, but it did after taking 20 or 40 grams of whey. Although the FSR (fiber synthesis rate) was higher in the athletes that were given 40 grams whey, the difference in FSR between the 20 and the 40 gram group was not statistically significant.

The oxidation of the amino acid phenylalanine increased dramatically when 40 grams of whey was ingested. The researchers think that the body starts to burn amino acids at doses of whey above 20 grams.

“It remains unknown whether the optimal dose of protein for the maximal stimulation of muscle protein synthesis differs between the 120-kg athlete and 80-kg male exerciser compared with the 60-kg female exerciser”, the researchers write. “Future studies should be designed to fully elucidate how muscle mass or the amount of muscle mass exercised influences the response of MPS to different doses of protein.”

“GlaxoSmithKline Nutritional Healthcare was involved in the design, analysis, and interpretation of data”.

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.