New research from the University of Stirling, Scotland suggests that, contrary to popular belief, people with more muscle mass do not need more protein after resistance exercise, a development that could have significant implications for sports nutrition recommendations.

Health scientists observed no differences in the muscle growth response to protein between larger and smaller participants following a full body workout.

"There is a widely-held assumption that larger athletes need more protein, with nutrition recommendations often given in direct relation to body mass" said Kevin Tipton, Professor of Sport, Health and Exercise Science in the Faculty of Health Sciences and Sport.

"In our study, participants completed a bout of whole-body resistance exercise, where earlier studies – on which protein recommendations are based – examined the response to leg-only exercise. This difference suggests the amount of muscle worked in a single session has a bigger impact on the amount of protein needed afterwards than the amount of muscle in the body."

The researchers also found that muscles grew and recovered better after higher doses of protein. For example, consuming 40 grams of protein post-workout was more effective at stimulating muscle growth than 20 grams. Notably, however, this increase occurred irrespective of the size of the participants.

"Until now, the consensus among leading sports nutritionists, including the American College of Sports Medicine and the British Nutrition Foundation, is that weightlifters do not need more than around 25 grams of protein after exercise to maximally stimulate the muscle's ability to grow", Tipton said.

"In order for nutritionists to recommend the correct amount of protein we first need to consider specific demands of the workout, regardless of athletes' size. This throws commonly held recommendations into question and suggests the amount of protein our muscles need after exercise may be dependent on the type of workout performed. These results are limited to younger, trained men so we may see different results with other groups, such as older individuals or females digesting different amounts of protein."