Sports Medicine

, Volume 48, Issue 9, pp 2169–2178 | Cite as

Threshold of Energy Deficit and Lower-Body Performance Declines in Military Personnel: A Meta-Regression

  • Nancy E. Murphy
  • Christopher T. Carrigan
  • J. Philip Karl
  • Stefan M. Pasiakos
  • Lee M. MargolisEmail author
Systematic Review



Negative energy balance (EB) is common during military operations, diminishing body mass and physical performance. However, the magnitude of negative EB where performance would still be maintained is not well defined.


Our objective was to explore relationships between EB and physical performance during military operations and define an acceptable negative EB threshold where performance may be maintained.


A systematic search was performed for studies that measured EB and physical performance during military training. A total of 632 articles and technical reports were screened. Lower-body power and strength were the most common performance tests across investigations and were used as physical performance outcomes. Data were extracted from nine eligible studies containing 15 independent subgroups. Meta-regression assessed changes in performance in relation to study duration (days), average daily EB, and total EB (daily EB × duration).


Changes in physical performance were not associated with average daily EB or training duration. Total EB was associated with changes in lower-body power (r2 = 0.764, P < 0.001) and strength (r2 = 0.836, P < 0.001) independently and combined (r2 = 0.454, P = 0.002). Predictive equations generated from the meta-regression indicated that, for a zero to small (2%) decline in performance, total EB should be limited to − 5686 to − 19,109 kcal, for an entire operation, whereas total EB of − 39,243 to − 59,377 kcal will result in moderate (7%) to large (10%) declines in performance.


These data demonstrated that greater total negative EB is associated with declines in lower-body performance during military operations.



The authors wish to acknowledge Dr. Scott Montain for his critical review of this manuscript, as well as the authors of the papers included in this meta-analysis, and the subjects who volunteered their time and effort to further military research.

Compliance with Ethical Standards

The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. 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.


This work was supported by the U.S. Army Medical Research and Material Command.

Conflicts of interest

Nancy Murphy, Christopher Carrigan, J. Philip Karl, Stefan Pasiakos, and Lee Margolis have no conflicts of interest relevant to the content of this article.

Supplementary material

40279_2018_945_MOESM1_ESM.pdf (116 kb)
Supplementary material 1 (PDF 116 kb)
40279_2018_945_MOESM2_ESM.pdf (90 kb)
Supplementary material 2 (PDF 89 kb)
40279_2018_945_MOESM3_ESM.pdf (112 kb)
Supplementary material 3 (PDF 111 kb)


  1. 1.
    Tharion WJ, Lieberman HR, Montain SJ, Young AJ, Baker-Fulco CJ, Delany JP, et al. Energy requirements of military personnel. Appetite. 2005;44(1):47–65.CrossRefPubMedGoogle Scholar
  2. 2.
    Alemany JA, Nindl BC, Kellogg MD, Tharion WJ, Young AJ, Montain SJ. Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity. J Appl Physiol (1985). 2008;105(1):58–64.CrossRefGoogle Scholar
  3. 3.
    Opstad PK. The hypothalamo-pituitary regulation of androgen secretion in young men after prolonged physical stress combined with energy and sleep deprivation. Acta Endocrinol (Copenh). 1992;127(3):231–6.PubMedCrossRefGoogle Scholar
  4. 4.
    Henning PC, Park BS, Kim JS. Physiological decrements during sustained military operational stress. Mil Med. 2011;176(9):991–7.CrossRefPubMedGoogle Scholar
  5. 5.
    Nindl BC, Castellani JW, Warr BJ, Sharp MA, Henning PC, Spiering BA, et al. Physiological Employment Standards III: physiological challenges and consequences encountered during international military deployments. Eur J Appl Physiol. 2013;113(11):2655–72.CrossRefPubMedGoogle Scholar
  6. 6.
    Margolis LM, Crombie AP, McClung HL, McGraw SM, Rood JC, Montain SJ, et al. Energy requirements of US Army Special Operation Forces during military training. Nutrients. 2014;6(5):1945–55.CrossRefPubMedPubMedCentralGoogle Scholar
  7. 7.
    Margolis LM, Murphy NE, Martini S, Gundersen Y, Castellani JW, Karl JP, et al. Effects of supplemental energy on protein balance during 4-d Arctic military training. Med Sci Sports Exerc. 2016;48(8):1604–12.CrossRefPubMedGoogle Scholar
  8. 8.
    Margolis LM, Murphy NE, Martini S, Spitz MG, Thrane I, McGraw SM, et al. Effects of winter military training on energy balance, whole-body protein balance, muscle damage, soreness, and physical performance. Appl Physiol Nutr Metab. 2014;39(12):1395–401.CrossRefPubMedGoogle Scholar
  9. 9.
    Margolis LM, Rood J, Champagne C, Young AJ, Castellani JW. Energy balance and body composition during US Army special forces training. Appl Physiol Nutr Metab. 2013;38(4):396–400.CrossRefPubMedGoogle Scholar
  10. 10.
    Nindl BC, Barnes BR, Alemany JA, Frykman PN, Shippee RL, Friedl KE. Physiological consequences of US Army Ranger training. Med Sci Sports Exerc. 2007;39(8):1380.CrossRefPubMedGoogle Scholar
  11. 11.
    Montain SJ, Young AJ. Diet and physical performance. Appetite. 2003;40(3):255–67.CrossRefPubMedGoogle Scholar
  12. 12.
    Friedl KE, Moore RJ, Martinez-Lopez LE, Vogel JA, Askew EW, Marchitelli LJ, et al. Lower limit of body fat in healthy active men. J Appl Physiol (1985). 1994;77(2):933–40.CrossRefGoogle Scholar
  13. 13.
    Taylor HL, Buskirk ER, Brozek J, Anderson JT, Grande F. Performance capacity and effects of caloric restriction with hard physical work on young men. J Appl Physiol. 1957;10(3):421–9.CrossRefPubMedGoogle Scholar
  14. 14.
    Friedl KE. When does energy deficit affect soldier performance. In: Marriott BM, editor. Not eating enough. Washington, DC: National Academy Press; 1995. p. 253–83.Google Scholar
  15. 15.
    Fairbrother B, Shippee R, Kramer T, Askew W, Mays M, Popp K, et al. Nutritional and immunological assessment of soldiers during the special forces assessment and selection course. USARIEM tech report. 1995. p. 102.Google Scholar
  16. 16.
    Nindl BC, Leone CD, Tharion WJ, Johnson RF, Castellani JW, Patton JF, et al. Physical performance responses during 72 h of military operational stress. Med Sci Sports Exerc. 2002;34(11):1814–22.CrossRefPubMedGoogle Scholar
  17. 17.
    Wallace B, Small K, Brodley CE, Lau J, Trikalinos TA. Deploying an interactive machine learning system in an evidence-based practice center: abstrackr. In: ACM international health informatics symposium; 2012; Miami, FL; 2012. p. 819–24.Google Scholar
  18. 18.
    Welsh TT, Alemany JA, Montain SJ, Frykman PN, Tuckow AP, Young AJ, et al. Effects of intensified military field training on jumping performance. Int J Sports Med. 2008;29(1):45–52.CrossRefPubMedGoogle Scholar
  19. 19.
    Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097.CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Fallowfield JL, Delves SK, Hill NE, Cobley R, Brown P, Lanham-New SA, et al. Energy expenditure, nutritional status, body composition and physical fitness of Royal Marines during a 6-month operational deployment in Afghanistan. Br J Nutr. 2014;112(5):821–9.CrossRefPubMedGoogle Scholar
  21. 21.
    Jacobs I, van Loon Capt D, Pasut L, Pope J, Bell D, Kavanagh Maj M, et al. Physical performance and carbohydrate consumption in CF commandos during a 5-day field trial. USARIEM tech report. 1989. p. 36.Google Scholar
  22. 22.
    Johnson MJ, Friedl KE, Frykman PN, Moore RJ. Loss of muscle mass is poorly reflected in grip strength performance in healthy young men. Med Sci Sports Exerc. 1994;26(2):235–40.CrossRefPubMedGoogle Scholar
  23. 23.
    Moore RJ, Friedl KE, Kramer TR, Martinez-Lopez LE, Hoyt RW, Tulley RE, et al. Changes in soldier nutritional status and immune function during the ranger training course. USARIEM Tech Rep. 1992;T13–92:162.Google Scholar
  24. 24.
    Nindl BC, Friedl KE, Frykman PN, Marchitelli LJ, Shippee RL, Patton JF. Physical performance and metabolic recovery among lean, healthy men following a prolonged energy deficit. Int J Sports Med. 1997;18(5):317–24.CrossRefPubMedGoogle Scholar
  25. 25.
    Shippee R, Friedl KE, Kramer T, Mays M, Popp K, Askew EW, et al. Nutritional and immunological assessment of ranger students with increased caloric intake. USARIEM Tech Rep. 1994;T95–5:212.Google Scholar
  26. 26.
    Fortes MB, Diment BC, Greeves JP, Casey A, Izard R, Walsh NP. Effects of a daily mixed nutritional supplement on physical performance, body composition, and circulating anabolic hormones during 8 weeks of arduous military training. Appl Physiol Nutr Metab. 2011;36(6):967–75.CrossRefPubMedGoogle Scholar
  27. 27.
    Williams AG, Rayson MP. Can simple anthropometric and physical performance tests track training-induced changes in load-carriage ability? Mil Med. 2006;171(8):742–8.CrossRefPubMedGoogle Scholar
  28. 28.
    Harman EA, Gutekunst DJ, Frykman PN, Sharp MA, Nindl BC, Alemany JA, et al. Prediction of simulated battlefield physical performance from field-expedient tests. Mil Med. 2008;173(1):36–41.CrossRefPubMedGoogle Scholar
  29. 29.
    Bishop PA, Fielitz LR, Crowder TA, Anderson CL, Smith JH, Derrick KR. Physiological determinants of performance on an indoor military obstacle course test. Mil Med. 1999;164(12):891–6.CrossRefPubMedGoogle Scholar
  30. 30.
    Friedl KE, Knapik JJ, Hakkinen K, Baumgartner N, Groeller H, Taylor NA, et al. Perspectives on aerobic and strength influences on military physical readiness: report of an International Military Physiology Roundtable. J Strength Cond Res. 2015;29(Suppl 11):S10–23.CrossRefPubMedGoogle Scholar
  31. 31.
    Hoyt RW, Opstad PK, Haugen AH, DeLany JP, Cymerman A, Friedl KE. Negative energy balance in male and female rangers: effects of 7 d of sustained exercise and food deprivation. Am J Clin Nutr. 2006;83(5):1068–75.CrossRefPubMedGoogle Scholar
  32. 32.
    Siri WE. The gross composition of the body. Adv Biol Med Phys. 1956;4:239–80.CrossRefPubMedGoogle Scholar
  33. 33.
    Tsafnat G, Glasziou P, Choong MK, Dunn A, Galgani F, Coiera E. Systematic review automation technologies. Syst Rev. 2014;3:74.CrossRefPubMedPubMedCentralGoogle Scholar
  34. 34.
    Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions. Chichester: Wiley; 2011. p. 488–524.Google Scholar
  35. 35.
    Van Rhee HJ. User manual for meta-essentials: workbooks for meta-analysis. Rotterdam: Erasmus Research Institute of Management; 2015. p. 1–43.Google Scholar
  36. 36.
    Borenstein M, Hedges LV, Higgins JPT. Introduction to meta-analysis. Chichester: Wiley; 2009. p. 17–49.CrossRefGoogle Scholar
  37. 37.
    Cohen J. Statistical power analysis for the behavioral sciences. Hillsdale: Lawrence Erlbaum Associates; 1988. p. 19–66.Google Scholar
  38. 38.
    Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–68.CrossRefPubMedGoogle Scholar
  39. 39.
    Fogelholm M. Effects of bodyweight reduction on sports performance. Sports Med. 1994;18(4):249–67.CrossRefPubMedGoogle Scholar
  40. 40.
    Pasiakos SM, Margolis LM. Negative energy balance and loss of body mass and fat-free mass in military personnel subsisting on combat rations during training and combat operations: a comment on Tassone and Baker. Br J Nutr. 2017;117(6):894–6.CrossRefPubMedGoogle Scholar
  41. 41.
    Guezennec CY, Satabin P, Legrand H, Bigard AX. Physical performance and metabolic changes induced by combined prolonged exercise and different energy intakes in humans. Eur J Appl Physiol Occup Physiol. 1994;68(6):525–30.CrossRefPubMedGoogle Scholar
  42. 42.
    Franchini E, Brito CJ, Artioli GG. Weight loss in combat sports: physiological, psychological and performance effects. J Int Soc Sports Nutr. 2012;9(1):52.CrossRefPubMedPubMedCentralGoogle Scholar
  43. 43.
    Friedl KE, Moore RJ, Hoyt RW, Marchitelli LJ, Martinez-Lopez LE, Askew EW. Endocrine markers of semistarvation in healthy lean men in a multistressor environment. J Appl Physiol (1985). 2000;88(5):1820–30.CrossRefGoogle Scholar
  44. 44.
    Johnson HL, Krzywicki HJ, Canham JE, Skala TA, Daws RA, Nelson RA, et al. Evaluation of calorie requirements for ranger training at Fort Benning, Georgia. Letterman Army Institute of Research tech report 1976; 34, AD A070 880.Google Scholar
  45. 45.
    Peltonen H, Walker S, Hakkinen K, Avela J. Neuromuscular fatigue to power loading using a weight-stack device fitted with or without additional rubber band resistance. J Strength Cond Res. 2014;28(7):1802–11.CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing (Outside the USA) 2018

Authors and Affiliations

  • Nancy E. Murphy
    • 1
  • Christopher T. Carrigan
    • 1
  • J. Philip Karl
    • 1
  • Stefan M. Pasiakos
    • 1
  • Lee M. Margolis
    • 1
    • 2
    Email author
  1. 1.Military Nutrition DivisionUS Army Research Institute of Environmental Medicine (USARIEM)NatickUSA
  2. 2.Oak Ridge Institute for Science and EducationOak RidgeUSA

Personalised recommendations