Time-divided ingestion pattern of casein-based protein supplement stimulates an increase in fat-free body mass during resistance training in young untrained men

Nutr Res. 2009 Jun;29(6):405-13. doi: 10.1016/j.nutres.2009.03.008.


We hypothesized that during prolonged resistance training, time-divided ingestion pattern of casein-based protein supplement is of superior efficiency in comparison with the ingestion of the same supplement immediately before each training session. In a crossover study, 13 men aged 18 to 19 years were evaluated during 2 well-controlled, 8-week training and supplementation periods. In the time-focused supplementation regimen (TFR), the subjects consumed the supplement in the morning and in the afternoon, immediately before the training session. Time-divided supplementation regimen (TDR) included 1 morning dose, whereas the second dose was ingested in the evening, 5 hours after training. The daily dose of the supplement contained approximately 70 g of protein (82% casein) and less than 1 g of carbohydrate and fat. Body mass, body composition (dual-energy x-ray absorptiometry scanned), and one-repetition maximum (1RM) for bench press and squat were determined at the beginning and at the end of both 8-week training and supplementation periods. Training produced a significant increase in 1RM strength both in the bench press (9.4% and 7.2%) and the squat exercise (10.7% and 17.8%) in the TFR and TDR, respectively, with no differences between the supplementation regimens. Fat-free mass increased from 62.4 +/- 1.2 to 63.5 +/- 1.3 kg (P = .046) with TDR, whereas no change was evident with TFR. The increase in 1RM strength in the squat exercise was related to the increase in fat-free mass in TDR (r = 0.569; P = .041). These findings may have practical implications for the timing of ingestion of protein supplements to enhance the efficacy of resistance training.

Publication types

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

MeSH terms

  • Absorptiometry, Photon
  • Adolescent
  • Analysis of Variance
  • Body Composition / physiology*
  • Body Mass Index
  • Caseins / administration & dosage*
  • Cross-Over Studies
  • Dietary Proteins / metabolism
  • Dietary Supplements*
  • Eating / physiology*
  • Feeding Behavior
  • Humans
  • Male
  • Muscle Strength / physiology
  • Physical Fitness
  • Resistance Training*
  • Statistics, Nonparametric
  • Students
  • Thinness*
  • Time Factors
  • Young Adult


  • Caseins
  • Dietary Proteins