title: Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit.
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.
authors.affiliation: Exercise and Nutrition Research Group, Health Innovations Research Institute, School of Medical Sciences, RMIT University, Melbourne, Australia;
authors.forename: José L
authors.initials: JL
authors.lastname: Areta
authors.forename: Louise M
authors.initials: LM
authors.lastname: Burke
authors.forename: Donny M
authors.initials: DM
authors.lastname: Camera
authors.forename: Daniel W D
authors.initials: DW
authors.lastname: West
authors.forename: Siobhan
authors.initials: S
authors.lastname: Crawshay
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Moore
authors.forename: Trent
authors.initials: T
authors.lastname: Stellingwerff
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Phillips
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
authors.forename: Vernon G
authors.initials: VG
authors.lastname: Coffey
mesh_terms: D000328:Adult; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D015536:Down-Regulation; D004435:Eating; D004734:Energy Metabolism / Q000187:drug effects; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000378:metabolism*; D014176:Protein Biosynthesis; D055070:Resistance Training; D012146:Rest / Q000502:physiology*; D055815:Young Adult
chemical_list: D004044:Dietary Proteins; D009124:Muscle Proteins
keywords: body composition; fat-free mass; myofibrillar protein synthesis; weight loss