Meal replacement in isolated and confined mission environments: Consumption, acceptability, and implications for physical and behavioral health

• Published in: Physiology & behavior Vol. 219; p. 112829
• Main Authors: Sirmons, Takiyah A., Roma, Peter G., Whitmire, Alexandra M., Smith, Scott M., Zwart, Sara R., Young, Millennia, Douglas, Grace L.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.05.2020
• Subjects: Behavioral health; breakfast; emotions; energy intake; flavor; food acceptability; food intake; habitats; humans; Meal replacement; Menu fatigue; satiety; space flight; Spaceflight; texture; Weight loss; Meal replacement; Behavioral health; Spaceflight; Weight loss; Menu fatigue
• ISSN: 0031-9384; 1873-507X; 1873-507X
• DOI: 10.1016/j.physbeh.2020.112829

We appreciate the reviewers’ time and recommendations, and have revised the manuscript to clarify questions. The changes are summarized here.•Energy equivalent meal replacement bars (MRBs) could conserve resources in isolated and confined operational environments.•MRB implementation was associated with reduced caloric intake, weight loss, and impacts to behavioral health.•Limited variety in flavor and texture, menu fatigue, and daily MRB implementation contribute to these negative impacts.•Meal replacement is operationally feasible and moderately acceptable for short-duration (<30d) missions. Strategies that reduce food system mass without negatively impacting food intake, acceptability, and resulting astronaut health and performance are essential for mission success in extreme operational environments such as space exploration. Here, we report the impact of substituting the spaceflight standard breakfast with energy equivalent, calorically-dense meal replacement bars (MRBs) on consumption, acceptability, and satiety and on associations with physical and behavioral health outcomes in high-performing subjects completing 30-day missions in the isolated and confined operational environment of NASA's Human Exploration Research Analog (HERA) habitat. MRB implementation was associated with reduced daily caloric intake, weight loss, and decrements in mood and neurobehavioral functioning, with no significant impacts on somatic symptoms and physical functioning. Food acceptability ratings suggest that flavor, texture, and menu fatigue attributed to limited variety are contributing factors, which are exacerbated by a daily implementation schedule. Meal replacement strategies for short-duration missions are operationally feasible, moderately acceptable, and can contribute to the practical goal of mass reduction, but more work is needed to define and optimize flavors, variety, and implementation schedules that sustain adequate nutrition, physical and behavioral health, and operational performance over time in isolated, confined, and extreme mission environments.