Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit

Am J Physiol Endocrinol Metab. 2014 Apr 15;306(8):E989-97. doi: 10.1152/ajpendo.00590.2013. Epub 2014 Mar 4.

Abstract

The myofibrillar protein synthesis (MPS) response to resistance exercise (REX) and protein ingestion during energy deficit (ED) is unknown. In young men (n = 8) and women (n = 7), we determined protein signaling and resting postabsorptive MPS during energy balance [EB; 45 kcal·kg fat-free mass (FFM)(-1)·day(-1)] and after 5 days of ED (30 kcal·kg FFM(-1)·day(-1)) as well as MPS while in ED after acute REX in the fasted state and with the ingestion of whey protein (15 and 30 g). Postabsorptive rates of MPS were 27% lower in ED than EB (P < 0.001), but REX stimulated MPS to rates equal to EB. Ingestion of 15 and 30 g of protein after REX in ED increased MPS ~16 and ~34% above resting EB (P < 0.02). p70 S6K Thr(389) phosphorylation increased above EB only with combined exercise and protein intake (~2-7 fold, P < 0.05). In conclusion, short-term ED reduces postabsorptive MPS; however, a bout of REX in ED restores MPS to values observed at rest in EB. The ingestion of protein after REX further increases MPS above resting EB in a dose-dependent manner. We conclude that combining REX with increased protein availability after exercise enhances rates of skeletal muscle protein synthesis during short-term ED and could in the long term preserve muscle mass.

Keywords: body composition; fat-free mass; myofibrillar protein synthesis; weight loss.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Dietary Proteins / administration & dosage
  • Dietary Proteins / pharmacology*
  • Down-Regulation
  • Eating
  • Energy Metabolism* / drug effects
  • Exercise Test
  • Female
  • Humans
  • Male
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / metabolism*
  • Protein Biosynthesis
  • Resistance Training*
  • Rest / physiology*
  • Young Adult

Substances

  • Dietary Proteins
  • Muscle Proteins