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Effects of high protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial

Permanent URL:
http://handle.nal.usda.gov/10113/58116
Abstract:
Context: The benefits of high protein diets for sparing lean body mass and sustaining skeletal muscle protein metabolism during short-term weight loss in normal-weight adults are not well described. Objective: Determine the effects of varying levels of dietary protein intake on body composition and muscle protein synthesis (MPS) during energy deficit (ED). Design, Setting, and Participants: A randomized controlled trial of 39 recreationally active adults (19-42 years, body mass index 22-29 kg/m2) admitted to a residential metabolic ward between October 2010 and November 2011. Intervention: Volunteers were assigned diets providing protein at 0.8 (recommended dietary allowance; RDA), 1.6 (2X-RDA), and 2.4 (3X-RDA) g·kg-1·d-1 for 31 days. A 10-day weight maintenance (WM) period was followed by 21 days of ED, during which energy intake was restricted to 60% of daily requirements. Main Outcome Measures: Body composition was measured by dual-energy x-ray absorptiometry during WM (day 9) and ED (day 30). Postabsorptive (PA) and postprandial (PP, mixed meal with 20 g protein) MPS were determined at rest during WM (day 10) and ED (day 31) using muscle biopsies and primed, constant L-[2H5]-phenylalanine infusions. Results: Overall, volunteers lost (P < 0.05) 3.2 ± 0.2 kg body weight during ED regardless of dietary protein. However, the proportion of weight loss attributed to reductions in fat-free mass was lower (P < 0.05) and the loss of fat mass was higher (P < 0.05) for 2X-RDA and 3X-RDA compared to RDA. The anabolic skeletal muscle response to a protein rich meal ('PP-PA MPS) during ED was not different (P > 0.05) from WM for 2X-RDA and 3X-RDA, but was lower during ED than WM for those consuming RDA levels of protein (energy-by-protein interaction, P< 0.05). Conclusions: These findings suggest that normal-weight adults may gain a metabolic advantage that protects muscle mass during short-term weight loss by consuming dietary protein above the RDA. Consuming high protein diets during weight loss may spare lean body mass and sustain skeletal muscle anabolic responses to dietary protein.
Author(s):
STEFAN M. PASIAKOS , JAY J. CAO , LEE M. MARGOLIS , EDWARD R. SAUTER , LEAH D. WHIGHAM , JAMES P. McCLUNG , JENNIFER C. ROOD , JOHN W. CARBONE , GERALD F. COMBS Jr. , ANDREW J. YOUNG
Subject(s):
Recommended Dietary Allowances , adults , body fat , body mass index , dietary protein , dual-energy X-ray absorptiometry , energy intake , fat free mass , high protein diet , lean body mass , muscle protein , protein intake , protein synthesis , randomized clinical trials , skeletal muscle , volunteers , weight control , weight loss
Source:
Journal of Federation of American Societies for Experimental Biology 2013 6 5 v.27
Language:
English
Year:
2013
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
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Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.