Distribution of Dietary Protein Intake in Daily Meals Influences Skeletal Muscle Hypertrophy Via the Circadian Clock

Abstract

Meal distribution of protein throughout the day is usually skewed. However, its physiological implications and the effects of better protein distribution on muscle volume are largely unknown. Here, using the two-meal-per-day-feeding model, we found that protein intake at the early active phase, according to the circadian clock, promoted overloading-induced muscle hypertrophy. We found that mice that were fed branched chain amino acid (BCAA)-supplemented diets at the early active phase demonstrated skeletal muscle hypertrophy. However, distribution-dependent effects were not observed in ClockΔ19 mice. Additionally, we examined the relationship between distribution of protein in meals and muscle functions such as skeletal muscle index and grip strength. In humans, higher muscle functions were observed in subjects who took dietary proteins mainly at breakfast than at dinner. These data suggest that protein intake at breakfast could be better for the maintenance of skeletal muscle mass.