title: Increased protein intake reduces lean body mass loss during weight loss in athletes.
abstract: OBJECTIVE
  To examine the influence of dietary protein on lean body mass loss and performance during short-term hypoenergetic weight loss in athletes.
  
  
  METHODS
  In a parallel design, 20 young healthy resistance-trained athletes were examined for energy expenditure for 1 wk and fed a mixed diet (15% protein, 100% energy) in the second week followed by a hypoenergetic diet (60% of the habitual energy intake), containing either 15% (approximately 1.0 g x kg(-1)) protein (control group, n = 10; CP) or 35% (approximately 2.3 g x kg(-1)) protein (high-protein group, n = 10; HP) for 2 wk. Subjects continued their habitual training throughout the study. Total, lean body, and fat mass, performance (squat jump, maximal isometric leg extension, one-repetition maximum (1RM) bench press, muscle endurance bench press, and 30-s Wingate test) and fasting blood samples (glucose, nonesterified fatty acids (NEFA), glycerol, urea, cortisol, free testosterone, free Insulin-like growth factor-1 (IGF-1), and growth hormone), and psychologic measures were examined at the end of each of the 4 wk.
  
  
  RESULTS
  Total (-3.0 +/- 0.4 and -1.5 +/- 0.3 kg for the CP and HP, respectively, P = 0.036) and lean body mass loss (-1.6 +/- 0.3 and -0.3 +/- 0.3 kg, P = 0.006) were significantly larger in the CP compared with those in the HP. Fat loss, performance, and most blood parameters were not influenced by the diet. Urea was higher in HP, and NEFA and urea showed a group x time interaction. Fatigue ratings and "worse than normal" scores on the Daily Analysis of Life Demands for Athletes were higher in HP.
  
  
  CONCLUSIONS
  These results indicate that approximately 2.3 g x kg(-1) or approximately 35% protein was significantly superior to approximately 1.0 g x kg(-1) or approximately 15% energy protein for maintenance of lean body mass in young healthy athletes during short-term hypoenergetic weight loss.
authors.affiliation: School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Samuel
authors.initials: S
authors.lastname: Mettler
authors.forename: Nigel
authors.initials: N
authors.lastname: Mitchell
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Tipton
mesh_terms: D000293:Adolescent; D000328:Adult; D001823:Body Composition; D015992:Body Mass Index; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D006801:Humans; D008297:Male; D013177:Sports; D015431:Weight Loss / Q000502:physiology*; D055815:Young Adult
chemical_list: D004044:Dietary Proteins