More Muscle Mass Means a Higher Protein Intake, Right?
New research from the University of Stirling has found individuals with more muscle mass do not need relatively more protein after resistance training.
Young, resistance-trained males were recruited for the study and divided into two groups. The first group had a lean body mass (LBM) of less than 65kg and the second had a higher LBM of more than 70kg. Each participant took part in two trials where they consumed protein after resistance exercise. In one trial, participants consumed 20g of whey protein and in the second, participants consumed 40g of whey protein after exercise. Scientists measured the muscle’s growth ability at an increased rate with metabolic tracers and muscle biopsies.
A member of the research team, Keith Tipton, highlighted the study’s use of whole body exercises as opposed to earlier studies which examined the response to leg-only exercise. These studies, Tipton claimed, are the basis on which current protein recommendations are based.
“There is a widely-held assumption that larger athletes need more protein, with nutrition recommendations often given in direct relation to body mass. 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.”
The research corroborated Tipton's point. The study's findings found no difference in the muscle growth response between the larger and smaller participants. Their muscles were able to grow and recover from exercise better after a higher dose of protein – i.e., consuming 40g of protein after exercise was more effective at stimulating muscle growth than 20g - but this increase occurred irrespective of the size of the participants.1
So Who Do We Believe?
Macronutrients and calorie recommendations are an inexact science. The most popular caloric equations used by nutritionists and registered dietiticians worldwide have an acceptable fallibility rate of around 10%, which rises to around 40% when treating obese populations.2 Their use is as a baseline from which individual adjustments and ameliorations can be made. Experimenters with intermittent fasting and the ketogenic diet also insinuate that traditional protein consumption guidelines (that stipulate intake should be regular, frequent, and at least 30-40% of our total caloric intake) overstress protein’s input to training recovery and general wellbeing. Their evidence at this time is anecdotal, but certainly provocative.
This study's finding that protein intake is correlated to the type of exercise, not the exerciser, is a novel one. But the need for more research is clear. As the research sample was limited to younger and well-trained men, women and populations who are not acclimatized to regular resistance training may yet need protein adjustments according to their LBM distribution.
1. The response of muscle protein synthesis following whole‐body resistance exercise is greater following 40 g than 20 g of ingested whey protein Lindsay S. Macnaughton et al. Physiological Reports Aug 2016, 4 (15) e12893; DOI: 10.14814/phy2.12893
2.The Essentials of Sport and Exercise Nutrition. Berardi, John & Andrews, Ryan (Precision Nutrition, 2014)