Supplementing An Energy Adequate High Protein Diet With Additional Protein Is Not Necessary For Recovery Of Lean Body Mass After Short-term Starvation

Abstract

Energy deficits during military operations can reach near complete starvation and result in significant reductions in lean body mass (LBM). Inadequate recovery of LBM may compromise subsequent performance. Consuming supplemental high-quality protein may accelerate LBM recovery by leveraging the anabolic properties of amino acids. PURPOSE: To characterize the effects of severe energy deficit on body composition and determine whether supplemental protein enhances LBM accretion during recovery. METHODS: Body composition (dual energy x-ray absorptiometry) and cross-sectional area (CSA) of the thigh (peripheral quantitative computed tomography) were measured before (BASELINE) and after (POST) a 7-d, near complete starvation caused by Survival, Evasion, Resistance, and Escape School (SERE) in 63 male U.S. Marines (mean ± SD, 25 ± 2 y, 84 ± 9 kg). POST SERE, volunteers were randomized to receive supplements high in carbohydrate (975 kcal, 224 g CHO, 3 g PRO; n=21), moderate in protein (910 kcal, 123 g CHO, 87 g PRO; n=24), or high in protein (1055 kcal, 106 g CHO, 139 g PRO; n=18) during a 27-d recovery period (REC). Supplements were consumed daily, in addition to their self-selected, ad libitum diet. Dietary intake was calculated using 24-hr recalls and body composition measurements were repeated at the end of REC. RESULTS: For all participants, total body mass (TBM) (7.2 ± 1.0%; 5.8 ± 1.0 kg; P < 0.05) and CSA (5.9 ± 2.2%; P < 0.05) was lower POST SERE compared to BASELINE. The decline in LBM (4.7 ± 2.5%; 3.1 ± 1.6 kg; P < 0.05) accounted for 53% of the TBM loss. During REC, no differences were observed in total energy intake when self-selected diets and supplement intake were combined (4498 ± 1191 kcal/d; P > 0.05); however, per study design, protein intake was significantly different between groups (high carbohydrate: 1.9 ± 0.6 g/kg/d; moderate protein: 3.1 ± 0.9 g/kg/d; high protein: 3.4 ± 0.9 g/kg/d; P < 0.01). At REC, and independent of group assignment, all participants regained TBM (8.0 ± 2.8%), LBM (5.7 ± 2.9%), and CSA (7.4 ± 3.2%) from POST SERE deficits, resulting in no differences between BASELINE and REC measures (P > 0.05). CONCLUSION: These data suggest that supplementing energy adequate high protein (~2.0 g·kg-1·d-1) diets with additional protein does not enhance LBM recovery from short-term starvation.