|Whigham Grendell, Leah|
Submitted to: International Journal of Obesity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2013
Publication Date: 7/1/2014
Publication URL: http://handle.nal.usda.gov/10113/59633
Citation: Pasiokos, S.M., Margolis, L.M., Mcclung, J.P., Cao, J.J., Whigham Grendell, L.D., Combs, G.F., Young, A.J. 2014. Whole-body protein turnover response to short-term high-protein diets during weight loss: a randomized controlled trial. International Journal of Obesity. 38(7):1015-1018. Interpretive Summary: Consuming high protein diets may decrease protein loss during energy deficit. To determine whole-body protein responses to high protein diets during weight loss, we conducted a randomized controlled trial with thirty-nine young healthy adults who consumed three different dietary protein levels. The study included a 10-day weight maintenance period and a 21-day, 40% energy deficit period. We measured whole-body protein turnover using stable isotope. We demonstrated that consuming dietary protein at levels above the current recommendation preserved lean body mass and improved protein utilization during short-term weight loss.
Technical Abstract: Objective: Determine whole-body protein turnover responses to high protein diets during weight loss. Design: Thirty-nine adults (age, 21 ± 1 yr; VO2peak, 48 ± 1 ml'kg-1'min-1; body mass index, 25 ± 1 kg•m2) were randomized to diets providing protein at the recommend dietary allowance (RDA), 2X-RDA, or 3X-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 [1-13C]-leucine. Results: 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, whereas feeding attenuated (P < 0.05) breakdown during weight maintenance but not energy deficit. Oxidation increased (P < 0.05) linearly 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 linearly between dietary protein levels, but in the FED state, net balance was lower for 3X-RDA as compared to RDA and 2X-RDA (diet-by-state, P < 0.05). Conclusion: Consuming dietary protein at levels exceeding the RDA during short-term weight loss upregulates protein oxidation but does not enhance whole-body protein balance.