title: Supplementing an energy adequate, higher protein diet with protein does not enhance fat-free mass restoration after short-term severe negative energy balance.
abstract: Negative energy balance during military operations can be severe and result in significant reductions in fat-free mass (FFM). Consuming supplemental high-quality protein following such military operations may accelerate restoration of FFM. Body composition (dual-energy X-ray absorptiometry) and whole body protein turnover (single-pool [15N]alanine method) were determined before (PRE) and after 7 days (POST) of severe negative energy balance during military training in 63 male US Marines (means ± SD, 25 ± 3 yr, 84 ± 9 kg). After POST measures were collected, volunteers were randomized to receive higher protein (HIGH: 1,103 kcal/day, 133 g protein/day), moderate protein (MOD: 974 kcal/day, 84 g protein/day), or carbohydrate-based low protein control (CON: 1,042 kcal/day, 7 g protein/day) supplements, in addition to a self-selected, ad libitum diet, for the 27-day intervention (REFED). Measurements were repeated POST-REFED. POST total body mass (TBM; -5.8 ± 1.0 kg, -7.0%), FFM (-3.1 ± 1.6 kg, -4.7%), and net protein balance (-1.7 ± 1.1 g protein·kg-1·day-1) were lower and proteolysis (1.1 ± 1.9 g protein·kg-1·day-1) was higher compared with PRE (P< 0.05). Self-selected, ad libitum dietary intake during REFED was similar between groups (3,507 ± 730 kcal/day, 2.0 ± 0.5 g protein·kg-1·day-1). However, diets differed by protein intake due to supplementation (CON: 2.0 ± 0.4, MOD: 3.2 ± 0.7, and HIGH: 3.5 ± 0.7 g·kg-1·day-1;P< 0.05) but not total energy (4,498 ± 725 kcal/day). All volunteers, independent of group assignment, achieved positive net protein balance (0.4 ± 1.0 g protein·kg-1·day-1) and gained TBM (5.9 ± 1.7 kg, 7.8%) and FFM (3.6 ± 1.8 kg, 5.7%) POST-REFED compared with POST (P< 0.05). Supplementing ad libitum, energy-adequate, higher protein diets with additional protein may not be necessary to restore FFM after short-term severe negative energy balance.NEW & NOTEWORTHYThis article demonstrates1) the majority of physiological decrements incurred during military training (e.g., total and fat-free mass loss), with the exception of net protein balance, resolve and return to pretraining values after 27 days and2) protein supplementation, in addition to an ad libitum, higher protein (~2.0 g·kg-1·day-1), energy adequate diet, is not necessary to restore fat-free mass following short-term severe negative energy balance.
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.|Oak Ridge Institute for Science and Education, Belcamp, Maryland; and.
authors.forename: C E
authors.initials: CE
authors.lastname: Berryman
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.
authors.forename: J J
authors.initials: JJ
authors.lastname: Sepowitz
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.
authors.forename: H L
authors.initials: HL
authors.lastname: McClung
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.
authors.forename: H R
authors.initials: HR
authors.lastname: Lieberman
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.|Oak Ridge Institute for Science and Education, Belcamp, Maryland; and.
authors.forename: E K
authors.initials: EK
authors.lastname: Farina
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.
authors.forename: J P
authors.initials: JP
authors.lastname: McClung
authors.affiliation: Department of Geriatrics, Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
authors.forename: A A
authors.initials: AA
authors.lastname: Ferrando
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts; stefan.m.pasiakos.civ@mail.mil.
authors.forename: S M
authors.initials: SM
authors.lastname: Pasiakos
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D015992:Body Mass Index; D000073600:Diet, High-Protein / Q000379:methods; D004311:Double-Blind Method; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D008889:Military Personnel; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: casein; muscle; negative energy balance; protein balance; recovery; whey