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.

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.

Publication types

  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Body Mass Index
  • Diet
  • Dietary Proteins / administration & dosage*
  • Dietary Proteins / pharmacokinetics*
  • Energy Intake*
  • Exercise
  • Fasting
  • Female
  • Humans
  • Male
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism*
  • Postprandial Period
  • Weight Loss*

Substances

  • Dietary Proteins
  • Muscle Proteins