Minimal whey protein with carbohydrate stimulates muscle protein synthesis following resistance exercise in young men.

Whey protein is a supplemental protein source used by athletes, particularly those aiming to gain muscle mass; however, direct evidence for its efficacy in stimulating muscle protein synthesis (MPS) is lacking. We aimed to determine the impact of consuming whey protein on skeletal muscle protein turnover in the post‐exercise period. Eight healthy young men (BMI = 26.8±0.9; age = 21±1) participated in a double‐blind randomized cross‐over trial in which they performed a unilateral leg resistance exercise workout – EX – (4 sets of knee extensions and 4 sets of leg press – 8–10 reps per set), such that the other leg was not exercised and acted as a rested (RE) comparator. After exercise subjects consumed either an isocaloric whey protein plus carbohydrate beverage (10g whey and 21g fructose) – WHEY – or a carbohydrate beverage containing fructose and maltodextrin (21g and 10g, respectively) – CHO. Subjects received pulse‐tracer injections of L[ring‐2H5]phenylalanine and L‐[15N]phenylalanine to measure MPS. Exercise stimulated a rise in MPS only in the WHEY‐EX leg, which was greater than MPS in the WHEY‐RE leg and also the CHO‐EX leg (all P<0.01). We conclude that a small dose (10g) of whey protein with carbohydrate (21g) can stimulate a rise in MPS after resistance exercise which, overtime, would be supportive of a net muscle protein accrual and hypertrophy. Supported by the US National Dairy Council.