Body Composition and Physical Readiness in Military Servicemembers: Cross-Disciplinary Advances and Current Challenges

ABSTRACT This graphical review highlights recent advances and current challenges surrounding body composition and military physical readiness. First, the trade-offs between accuracy and feasibility for employing the approved body composition assessment techniques (e.g., multifrequency bioelectrical impedance analysis, circumference-based measurements) at scale in the US Armed Forces are described. Second, how the muscle-mass-sparing effects of supplemental protein may be limited to when energy deficits are modest and may fail when deficits are more severe (≥40% of total energy requirements) in austere conditions is described. Third, recent evidence for the relation between body composition and environmental stress is highlighted, including the increased risk of exertional heat stroke found in individuals with high body mass index, as well as knowledge gaps related to cold and high-altitude exposure. Fourth, the unclear role of body composition in menstrual dysfunction during military training is described. Fifth, the potential efficacy and unknown safety of anti-obesity medication use (i.e., incretin mimetic—glucagon-like peptide-1 agonists) in the military and during operational stress are highlighted. Together, these topics emphasize the persistent importance of body composition and its effect on military physical readiness, especially in the face of the current obesity crisis.