title: Whole-body protein turnover response to short-term high-protein diets during weight loss: a randomized controlled trial.
abstract: To determine whole-body protein turnover responses to high-protein diets during weight loss, 39 adults (age, 21±1 years; VO2peak, 48±1 ml kg(-1) min(-1); body mass index, 25±1 kg m(2)) were randomized to diets providing protein at the recommend dietary allowance (RDA), 2 × -RDA or 3 × -RDA. A 10-day weight maintenance period preceded a 21-day, 40% energy deficit. Postabsorptive (FASTED) and postprandial (FED) whole-body protein turnover was determined during weight maintenance (day 10) and energy deficit (day 31) using [1-(13)C]leucine. FASTED flux, synthesis and breakdown were lower (P<0.05) for energy deficit than weight maintenance. Protein flux and synthesis were higher (P<0.05) for FED than FASTED. Feeding attenuated (P<0.05) breakdown during weight maintenance but not energy deficit. Oxidation increased (P<0.05) between dietary protein levels and feeding stimulated oxidation, although oxidative responses to feeding were higher (P<0.05) for energy deficit than weight maintenance. FASTED net balance decreased between dietary protein levels, but in the FED state, net balance was lower for 3 × -RDA as compared with RDA and 2 × -RDA (diet-by-state, P<0.05). Consuming dietary protein at levels above the RDA, particularly 3 × -RDA, during short-term weight loss increases protein oxidation with concomitant reductions in net protein balance.
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Pasiakos
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Margolis
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: McClung
authors.affiliation: Grand Forks Human Nutrition Research Center, US Department of Agriculture, Agricultural Research Service, Grand Forks, ND, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Cao
authors.affiliation: Grand Forks Human Nutrition Research Center, US Department of Agriculture, Agricultural Research Service, Grand Forks, ND, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Whigham
authors.affiliation: Grand Forks Human Nutrition Research Center, US Department of Agriculture, Agricultural Research Service, Grand Forks, ND, USA.
authors.forename: G F
authors.initials: GF
authors.lastname: Combs
authors.affiliation: Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Young
mesh_terms: D000328:Adult; D015992:Body Mass Index; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D002149:Energy Intake; D015444:Exercise; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D019518:Postprandial Period; D015431:Weight Loss
chemical_list: D004044:Dietary Proteins; D009124:Muscle Proteins