Scientists have challenged sports nutrition recommendations on consuming protein after working out.

The research by Stirling University found no difference in response to protein after a full body workout between large and smaller participants.

Current thinking within sports nutrition suggests bigger athletes, such as body builders and weightlifters, need to consume more protein after exercising because of their body size.

The research found the nature of the exercise and amount of muscle worked are more significant factors in determining the amount of protein people consume after working out.

It also questioned if the guideline amount of 20g-25g post-workout protein was adequate for some.

Kevin Tipton, professor of sport, health and exercise science at the university said: "There is a widely held assumption that larger athletes need more protein, with nutrition recommendations often given in direct relation to body mass.

"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 research also found that in some cases the recommended protein intake after a workout - currently around 20g-25g - was not sufficient.

Professor Tipton said: "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 25g of protein after exercise to maximally stimulate the muscle's ability to grow.

"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."

The study took 30 young men and divided them into two groups - one with a lower body mass of 65kg and one with a body mass of more than 70kg.

They undertook two trials where all the athletes consumed protein shakes after resistance exercise.

In one they took 20g and in the other they had 40g of whey protein.

The scientists measured their muscles using metabolic tracers and found the growth rate increased for both groups equally after the larger intake of protein.