Carbohydrate does not augment exercise-induced protein accretion versus protein alone

Med Sci Sports Exerc. 2011 Jul;43(7):1154-61. doi: 10.1249/MSS.0b013e31820751cb.


Purpose: We tested the thesis that CHO and protein coingestion would augment muscle protein synthesis (MPS) and inhibit muscle protein breakdown (MPB) at rest and after resistance exercise.

Methods: Nine men (age=23.0±1.9 yr, body mass index=24.2±2.1 kg·m) performed two unilateral knee extension trials (four sets×8-12 repetitions to failure) followed by consumption of 25 g of whey protein (PRO) or 25 g of whey protein plus 50 g of maltodextrin (PRO+CARB). Muscle biopsies and stable isotope methodology were used to measure MPS and MPB.

Results: The areas under the glucose and insulin curves were 17.5-fold (P<0.05) and 5-fold (P<0.05) greater, respectively, for PRO+CARB than for PRO. Exercise increased MPS and MPB (both P<0.05), but there were no differences between PRO and PRO+CARB in the rested or exercised legs. Phosphorylation of Akt was greater in the PRO+CARB than in the PRO trial (P<0.05); phosphorylations of Akt (P=0.05) and acetyl coA carboxylase-β (P<0.05) were greater after exercise than at rest. The concurrent ingestion of 50 g of CHO with 25 g of protein did not stimulate mixed MPS or inhibit MPB more than 25 g of protein alone either at rest or after resistance exercise.

Conclusions: Our data suggest that insulin is not additive or synergistic to rates of MPS or MPB when CHO is coingested with a dose of protein that maximally stimulates rates of MPS.

Publication types

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

MeSH terms

  • Adult
  • Dietary Carbohydrates / administration & dosage*
  • Dietary Carbohydrates / metabolism
  • Dietary Proteins / administration & dosage
  • Dietary Proteins / metabolism
  • Eating
  • Exercise*
  • Humans
  • Insulin / blood
  • Knee / physiology
  • Male
  • Milk Proteins / administration & dosage
  • Milk Proteins / metabolism
  • Muscle Proteins / biosynthesis
  • Muscle Proteins / metabolism*
  • Muscle, Skeletal / metabolism*
  • Polysaccharides / administration & dosage
  • Polysaccharides / metabolism
  • Protein Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Whey Proteins
  • Young Adult


  • Dietary Carbohydrates
  • Dietary Proteins
  • Insulin
  • Milk Proteins
  • Muscle Proteins
  • Polysaccharides
  • Whey Proteins
  • maltodextrin
  • Protein Kinases
  • Proto-Oncogene Proteins c-akt
  • (acetyl-CoA carboxylase) kinase