The Association Between Whey Protein, Regional Fat Mass and Strength in Resistance-Trained Men: A Cross-Sectional Study.

The purpose of this study was to evaluate the association between whey protein supplementation, body composition and muscle strength, in resistance-trained individuals. Forty-nine healthy males, aged 18 to 35 years that were engaged in resistance training for at least one year, were assigned into two groups according to whey protein intake (Whey: n=26, 30.7 ± 7.4 yr, 75.8 ± 9.0 kg; WithoutWhey: n=23, 31.0 ± 7.4 yr, 77.9 ± 9.3 kg). Using a cross-sectional design, a morning assessment of body fat mass (FM) (by dual energy X-ray absorptiometry) and strength (using 1RM for bench press and back squat) was performed. Nutritional assessment was performed by 3-day food records. Regarding nutritional habits, differences between total energy intake (kcal) and estimated energy requirements (kcal) were observed. Results, from both raw data or controlling for energy intake, estimated energy requirements or achieved percentage of energy requirements, showed that whey protein supplementation was inversely correlated with whole-body FM (R=-0.367 (p=0.010); R=-0.317 (p=0.049); R=-0.380 (p=0.011); R=-0.321 (p=0.047), respectively), trunk FM (R=-0.396 (p=0.005), R=-0.367 (p=0.022), R=-0.423 (p=0.004), R=-0.369 (p=0.021), respectively) and android FM (R=-0.381 (p=0.007), R=-0.332 (p=0.039), R=-0.383 (p=0.010), R=-0.336 (p=0.036), respectively). No correlations were found between muscle strength outcomes and whey protein supplementation. The present data suggests that whey protein ingestion has a positive association with whole-body and regional (trunk and android) FM.