Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters

Abstract

Background: Acute consumption of fat-free fluid milk after resistance exercise promotes a greater positive protein balance than does soy protein.Objective: We aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on traininginduced lean mass accretion. Design: We recruited 56 healthy young men who trained 5 d/wk for 12 wk on a rotating split-body resistance exercise program in a parallel 3-group longitudinal design. Subjects were randomly assigned to consume drinks immediately and again 1 h after exercise: fat-free milk (Milk; n ҃ 18); fat-free soy protein (Soy; n ҃ 19) that was isoenergetic, isonitrogenous, and macronutrient ratio matched to Milk; or maltodextrin that was isoenergetic with Milk and Soy (control group; n ҃ 19). Results: Muscle fiber size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. No between-group differences were seen in strength. Type II muscle fiber area increased in all groups with training, but with greater increases in the Milk group than in both the Soy and control groups (P 0.05). Type I muscle fiber area increased after training only in the Milk and Soy groups, with the increase in the Milk group being greater than that in the control group (P 0.05). DXA-measured fat-and bone-free mass increased in all groups, with a greater increase in the Milk group than in both the Soy and control groups (P 0.05). Conclusion: We conclude that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.Am J Clin Nutr 2007; 86:373-81.

Postexercise protein ingestion increases whole body net protein balance in healthy children

“…In the present study, we provided milk proteins as the source of dietary nitrogen in the postexercise beverages given that they are complete, high-quality proteins that are generally associated with greater muscle remodeling and recovery after exercise in adults (32). For example, studies in adults have revealed that milk and associated dairy-based proteins (especially whey) support greater rates of muscle protein synthesis and net protein balance after exercise compared with plantbased proteins such as soy (38,46), which can ultimately translate into greater training-induced gains in muscle and lean body mass (20,44). The greater anabolic effect of dairy compared with soy protein in adults occurs despite these sources having similarly high [albeit artificially truncated (37)] protein quality ratings according to the protein digestibilitycorrected amino acid score (32).…”

Legumes and soy products consumption and functional disability in older women

“…Besides soy isoflavones, other soy constituents such as protein may affect muscle mass [29]. Several studies have indicated that high-quality proteins such as soy can support muscle protein synthesis [30][31][32].…”

Effect of whey protein isolate on rehydration after exercise

“…This potentially leads to beneficial adaptations during chronic exercise training (Hartman et al, 2007;Robinson et al 2011;Ferguson-Stegall et al 2011). Despite this, little is known about the effects of protein on post-exercise rehydration.…”