The role of dietary protein in body weight regulation among active-duty military personnel during energy deficit: a systematic review

Authors: ANDERSON, ROEBERT - University Of North Carolina; Casperson, Shanon; KHO, HANNAH - University Of Kentucky; FLACK, KYLE - University Of Kentucky

Submitted to: Nutrients
Publication Type: Review Article
Publication Acceptance Date: 9/9/2023
Publication Date: 9/12/2023
Citation: Anderson, R., Casperson, S.L., Kho, H., Flack, K.D. 2023. The role of dietary protein in body weight regulation among active-duty military personnel during energy deficit: a systematic review. Nutrients. 15(18):1-15. https://doi.org/10.3390/nu15183948.
DOI: https://doi.org/10.3390/nu15183948

Interpretive Summary: Military personnel are often subject to inadequate energy intake during periods of intense physical excretion, such as training exercises and combat, as proper nutrition can be difficult to attain. Therefore, understanding the nutritional needs of our active duty military during these is imperative to improve combat readiness. We performed a systematic review of the current research investigating the efficacy of increasing dietary protein intake during an ED, specifically focusing on body weight regulation (FM loss and FFM gain) among active-duty military personnel. We found only 8 studies that examined this issue. Results of these support the recommendation that greater than 0.8 grams per kilogram of body weight per day is necessary to mitigate the impact of energy deficit on declines in lean body mass, with an intake of 1.6 grams per kilogram of body weight per day may be preferred. Of great importance is that none of these studies included female soldiers. With women making up almost 20% of the active-duty force, this is a major gap in understanding nutritional needs of all active-duty service personnel during periods of energy deficits.

Technical Abstract: Active-duty military personnel are subjected to sustained periods of energy deficit during combat and training, leaving them susceptible to detrimental reductions in body weight. The importance of adequate dietary protein intake during periods of intense physical training is well established, with previous research primarily focused on muscle protein synthesis, muscle recovery, and physical performance. This review systematically identified the effect of dietary protein in body weight regulation among active-duty military during an energy deficit. A literature search based on fixed inclusion and exclusion criteria was performed. English language peer-reviewed journal articles from inception to June 3, 2023, were selected for extraction and quality assessment. Eight studies were identified with outcomes described narratively. Study duration ranged from eight days to six months. Protein was directly provided to participants in all studies except for one. Three studies supplied additional protein via supplementation. The Downs and Black Checklist was used to assess study quality. Five studies were classified as good, two as fair, and one as excellent. All studies reported mean weight loss following energy deficit, the most severe was 4.0 kg. Protein dose during energy deficit varied from 0.5 g/kg/d to 2.4 g/kg/d. Six studies reported mean reductions in fat mass, the largest being 4.5 kg. Four studies reported mean reductions in fat-free mass while two studies reported an increase. Results support the recommendation that greater than 0.8 g/kg/d is necessary to mitigate the impact of energy deficit on declines in lean body mass, while intakes up to 1.6 g/kg/d may be preferred. Longer and larger investigations are needed to elucidate protein’s role during energy deficit in active-duty military.