Effects of Consuming Protein-rich Supplements Between or With Meals on Changes in Body Composition with Resistance Training: A Systematic Review of Randomized Controlled Trials
Joshua L. Hudson FASEB 2017
Higher dietary protein intakes achieved through consuming protein-rich supplements may improve body composition with resistance training. With the recent interest in the potential for within-day dietary protein distribution to elicit differential changes in body composition, a similar investigation specifically on consuming protein-rich supplements is warranted. Therefore, the primary purpose of this systematic review of literature was to investigate whether consuming a protein-rich supplement between meals (BET) versus with meals (WITH) would differentially influence adaptive changes in body composition while performing resistance training. 1938 articles were identified with PubMed, Scopus, Cochrane, and CINAHL using the keywords “dietary protein,” “body composition,” “muscle strength,” and “lean mass.” Data from the outcome variables whole body mass, lean mass, and fat mass were collected from randomized controlled trials assessing the effect of consuming protein-rich supplements during resistance training (> 6 to ≤ 36 wk; median: 12 wk). Thirty randomized controlled trials resulting in 55 individual groups met the inclusion criteria and were included in this review.
Supplementation ranged from 10 to 113 g protein/d in the BET groups (mean ± SD; 48 ± 26 g/d (n=40)) and 10 to 75 g/d in the WITH groups (32 ± 23 g/d (n=15)). The frequency of supplementation ranged from 1–3 times daily in the BET and WITH groups (mean ± SD; 1 dose/d: BET: 37 ± 22 g protein/dose (n =18), WITH: 15 ± 5 g protein/dose (n=7); 2 doses/d: BET: 22 ± 10 g protein/dose (n=11), WITH: 19 ± 7 g protein/dose (n=5); 3 doses/d; BET: 24 ± 7 g protein/dose (n=11), WITH: 25 ± 0 g protein/dose (n=3)).
Protein-rich supplementation resulted in 73% of BET groups increasing body mass compared to 53% of WITH groups. Eighty-nine percent of BET groups gained lean mass compared to 93% of WITH groups; however, 52% percent of the BET groups gained ≥ 1.5 kg of lean mass compared to 14% of the WITH groups. Forty-three percent of BET groups gained fat mass compared to only 13% of WITH groups. In regards to changes in lean mass to fat mass ratio, 85% of BET group increased their ratio compared to 100% of WITH groups. When groups consuming > 75 g protein/d in the BET groups were excluded, 68% gained ≥ 0.0 kg body mass, 40% ≥ gained 1.5 kg lean mass, and 43% gained ≥ 0.0 kg fat mass
In conclusion, consuming protein-rich supplements between meals was apparently more effective at increasing whole body mass, lean mass, and fat mass in adults during resistance training.