Impact of Protein Intake on Exercise‐Induced Changes in Body Composition in Middle‐Aged, Overweight Adults

Abstract

Objective and MethodsThe impact of total protein intake (PI) on body composition was studied in 111 overweight, middle‐aged adults (age 48.8±0.6 y, BMI 30.1±0.5 kg/m2) who exercised 3d/week and consumed an unrestricted diet along with 200 kcal supplements (0, 10, 20 or 30 g whey protein) 2× daily for 36 wk. Protein intake was assessed via 4‐d food records. A multiple regression model retrospectively assessed the moderating effects of PI (Post study PI=1.2±0.37 g pro•kg−1•d−1) on exercise‐induced changes in body composition.ResultsTotal protein intake was inversely associated with the change over time in total mass, fat mass, body fat % (p<0.05), and lean mass (p<0.08, trend) and positively associated with the change in lean mass percent (p<0.02). The changes in body composition were different (p<0.01) between groups of subjects that consumed < vs. > 1.0 g pro•kg−1•d−1:total mass (1.68±0.52 vs. −0.18±0.4 SE), fat mass (−1.22±0.34 vs. 0.48±0.43 kg) body fat % (−1.4±0.24 vs. −0.23±0.29 %), lean mass percent (1.39±0.23 vs. 0.27±0.28 %).ConclusionConsumption of higher protein promotes positive changes in body composition in conjunction with exercise training. Protein intakes > 1.0 g pro•kg−1•d−1are preferred to help middle‐aged, overweight adults to help reduce body fat and to increase lean mass percent.Grant Funding Source: Support: NIH T32 AG025671 and UL1 RR025761, US Whey Consort, Purdue Ingest Behav Res Ctr