Effects of Dietary Protein on Musculoskeletal Health During Calorie Deficiency


Military personnel face many physiological challenges, including sustained physical activity and prolonged periods of negative energy balance. Chronic energy deficiency often results in a loss of skeletal muscle mass and can reduce overall bone health. Recent evidence suggests that dietary interventions that provide protein in excess of the current national dietary recommendation may confer protection against the negative effects of energy deficiency on the musculoskeletal system. The primary objective of this randomized, controlled study is to assess the effects dietary protein intake spanning the current acceptable macronutrient distribution range on musculoskeletal health following prolonged energy deficiency. Findings from this investigation will improve current understanding of dietary conditions necessary to reduce the damaging effects of caloric deficiency on musculoskeletal health in warfighters. Furthermore, given the rise in obesity in military populations, findings may aid in the development of nutritional weight management strategies that promote healthy weight loss without compromising musculoskeletal health.

Full Title of Study: “The Musculoskeletal Response to Energy Deficit: Defining Optimal Protein Intake”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Factorial Assignment
    • Primary Purpose: Basic Science
    • Masking: None (Open Label)
  • Study Primary Completion Date: November 2011


  • Other: Dietary Protein Intake
    • Protein intakes within the current recommendation

Arms, Groups and Cohorts

  • Experimental: Protein level 1
  • Experimental: Protein level 2
  • Experimental: Protein level 3

Clinical Trial Outcome Measures

Primary Measures

  • Change from weight maintenance in muscle metabolism after energy restriction
    • Time Frame: Measured after a 3 week energy deficit

Secondary Measures

  • Change from weight maintenance in bone metabolism after energy restriction
    • Time Frame: Measured after a 3 week energy deficit

Participating in This Clinical Trial

Inclusion Criteria

  • Weight stable with body mass index 22-29 kg/m2
  • Physically active
  • Refrain from NSAIDS and other aspirin containing medications
  • Refrain from alcohol and nicotine

Exclusion Criteria

  • Metabolic or cardiovascular abnormalities, gastrointestinal disorders
  • Disease or medication that affects metabolism and/or exercise
  • Allergies or intolerance to foods, vegetarian practices, or medications to be used in the study
  • Anemia and Sickle Cell Anemia/Trait; abnormal PT/PTT test or problems with blood clotting
  • Present condition of alcoholism, use of nutritional/sports supplements, anabolic steroids, or other substance abuse issues
  • Musculoskeletal injuries that compromise the ability to exercise
  • Blood donation within 8 weeks of beginning the study
  • Pregnancy and women not on contraceptives

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 42 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • United States Army Research Institute of Environmental Medicine
  • Collaborator
    • USDA Grand Forks Human Nutrition Research Center
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Stefan M Pasiakos, PhD, Principal Investigator, United States Army Research Institute of Environmental Medicine


Carbone JW, McClung JP, Pasiakos SM. Skeletal muscle responses to negative energy balance: effects of dietary protein. Adv Nutr. 2012 Mar 1;3(2):119-26. doi: 10.3945/an.111.001792. Review.

Citations Reporting on Results

Cao JJ, Pasiakos SM, Margolis LM, Sauter ER, Whigham LD, McClung JP, Young AJ, Combs GF Jr. Calcium homeostasis and bone metabolic responses to high-protein diets during energy deficit in healthy young adults: a randomized controlled trial. Am J Clin Nutr. 2014 Feb;99(2):400-7. doi: 10.3945/ajcn.113.073809. Epub 2013 Nov 27.

Pasiakos SM, Margolis LM, McClung JP, Cao JJ, Whigham LD, Combs GF, Young AJ. Whole-body protein turnover response to short-term high-protein diets during weight loss: a randomized controlled trial. Int J Obes (Lond). 2014 Jul;38(7):1015-8. doi: 10.1038/ijo.2013.197. Epub 2013 Oct 29.

Carbone JW, Margolis LM, McClung JP, Cao JJ, Murphy NE, Sauter ER, Combs GF Jr, Young AJ, Pasiakos SM. Effects of energy deficit, dietary protein, and feeding on intracellular regulators of skeletal muscle proteolysis. FASEB J. 2013 Dec;27(12):5104-11. doi: 10.1096/fj.13-239228. Epub 2013 Aug 21.

Pasiakos SM, Cao JJ, Margolis LM, Sauter ER, Whigham LD, McClung JP, Rood JC, Carbone JW, Combs GF Jr, Young AJ. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J. 2013 Sep;27(9):3837-47. doi: 10.1096/fj.13-230227. Epub 2013 Jun 5.

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