A new study challenges recommendation that men with more muscle need more protein

How much protein should we eat after exercise

In a recent study, researchers find that individuals with more muscle mass do not need more protein after resistance exercise. This means sports nutrition recommendations may undergo a significant shift.

In the study, health and exercise scientists from the University of Stirling found no difference in the muscle growth response to protein after a full body workout between larger and smaller participants.

There is a widely-held assumption that larger athletes need more protein, with nutrition recommendations often given in direct relation to body mass.

In the study, young, resistance-trained males were recruited and divided into two groups. One with lower lean body mass of less than 65 kg and one with higher lean body mass of more than 70 kg.

Both groups of participants completed a bout of whole-body resistance exercise.

The researchers found that 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.

In other words, how much protein you need is mainly determined by how many muscles you use in the exercise, not by your body size.

The experts also found that participants’ muscles were able to grow and recover from exercise better after a higher dose of protein.

Consuming 40 grams of protein after exercise was more effective at stimulating muscle growth than 20 grams. This increase occurred irrespective of the size of the participants.

The researchers suggest that 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.

In order for nutritionists to recommend the correct amount of protein, people 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.

However, these results are limited to younger, trained men. People may see different results with other groups, such as older individuals or females digesting different amounts of protein.

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Citation: Macnaughton LS, et al. (2016). The response of muscle protein synthesis following whole‐body resistance exercise is greater following 40 g than 20 g of ingested whey protein. Physiological Reports, 4: e12893. DOI: 10.14814/phy2.12893.
Figure legend: This Knowridge.com image is credited to University of Stirling.