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J Int Soc Sports Nutr. 2018 Apr 5;15:15. doi: 10.1186/s12970-018-0219-x. eCollection 2018.

Prediction equation for estimating total daily energy requirements of special operations personnel.

Author information

1Military Nutrition Division, US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA 01760 USA.
2Biophysics and Biomedical Modeling Division, US Army Research Institute of Environmental Medicine, Natick, MA USA.
3US Army Medical Department Center & School US Army Health Readiness Center of Excellence, US Military-Baylor University Graduate Program in Nutrition, San Antonio, TX USA.
4Oak Ridge Institute for Science and Education, Oak Ridge, TN USA.



Special Operations Forces (SOF) engage in a variety of military tasks with many producing high energy expenditures, leading to undesired energy deficits and loss of body mass. Therefore, the ability to accurately estimate daily energy requirements would be useful for accurate logistical planning.


Generate a predictive equation estimating energy requirements of SOF.


Retrospective analysis of data collected from SOF personnel engaged in 12 different SOF training scenarios. Energy expenditure and total body water were determined using the doubly-labeled water technique. Physical activity level was determined as daily energy expenditure divided by resting metabolic rate. Physical activity level was broken into quartiles (0 = mission prep, 1 = common warrior tasks, 2 = battle drills, 3 = specialized intense activity) to generate a physical activity factor (PAF). Regression analysis was used to construct two predictive equations (Model A; body mass and PAF, Model B; fat-free mass and PAF) estimating daily energy expenditures.


Average measured energy expenditure during SOF training was 4468 (range: 3700 to 6300) Kcal·d-1. Regression analysis revealed that physical activity level (r = 0.91; P < 0.05) and body mass (r = 0.28; P < 0.05; Model A), or fat-free mass (FFM; r = 0.32; P < 0.05; Model B) were the factors that most highly predicted energy expenditures. Predictive equations coupling PAF with body mass (Model A) and FFM (Model B), were correlated (r = 0.74 and r = 0.76, respectively) and did not differ [mean ± SEM: Model A; 4463 ± 65 Kcal·d- 1, Model B; 4462 ± 61 Kcal·d- 1] from DLW measured energy expenditures.


By quantifying and grouping SOF training exercises into activity factors, SOF energy requirements can be predicted with reasonable accuracy and these equations used by dietetic/logistical personnel to plan appropriate feeding regimens to meet SOF nutritional requirements across their mission profile.


Energy balance; Energy deficit; Energy expenditure; Military

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Conflict of interest statement

Participation in the study was voluntary, with written consent being obtained from each soldier before the initiation of data collection. This study was conducted after review and approval by the US Army Research Institute of Environmental Medicine Institutional Review Board. The investigators adhered to the policies for protection of human subjects as prescribed in Army Regulation 70–25, and the research was conducted in adherence with the provisions of 32 CFR part 219. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Army or the Department of Defense. Any citations of commercial organizations and trade names in this report do not constitute an official Department of the Army endorsement of approval of the products or services of these organizations.No individuals’ personal data were included in this manuscript.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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