title: Comparison of the effects of weight loss from a high-protein versus standard-protein energy-restricted diet on strength and aerobic capacity in overweight and obese men.
abstract: OBJECTIVE
  To compare the effects of two low-fat, hypoenergetic diets differing in carbohydrate-to-protein ratio, on strength and aerobic capacity measures in overweight and obese men.
  
  
  METHODS
  In a parallel design, 56 men (age, 45.5 ± 8.7 years; BMI, 33.6 ± 3.9 kg/m(2)) were randomly assigned to a low-fat, energy-restricted diet (7,000 kJ/day) with either high protein (HP: protein/carbohydrate/fat % energy, 35:40:25) or standard protein (SP, 17:58:25). Body weight, body composition, muscle strength and aerobic capacity were assessed at baseline and after 12 weeks.
  
  
  RESULTS
  Forty-two participants completed the study (HP, n = 21; SP, n = 21). Both groups experienced similar reductions in body weight (HP, -10.7 ± 5.3 kg [-9.8%]; SP, -8.7 ± 3.5 kg [-8.4%]) and fat-free mass (HP, -2.8 ± 3.6 kg; SP, -3.2 ± 2.7 kg; P < 0.001 time; P > 0.14 time × group interaction). There was a trend for a greater reduction in fat mass in the HP diet group, (-7.7 ± 4.3 kg [-21.2%] vs. -5.4 ± 3.3 kg [-15.1%]; P < 0.001 time; P = 0.06 time × group interaction). Absolute peak oxygen uptake did not change in either group (P = 0.39 time; P = 0.50 time × group interaction). Overall, in both groups, relative peak oxygen uptake increased (2.9 ± 2.8 ml kg(-1) min(-1) [8.9%]), peak isometric knee extensor strength increased (14.1 ± 35.7 Nm [7.1%]) and peak handgrip strength decreased (-1.6 ± 4.1 kg [-3%]) (P ≤ 0.02 time for all), with no diet effect (P ≤ 0.23 time × group interaction).
  
  
  CONCLUSIONS
  In overweight and obese men, both a HP and SP diet reduced body weight and improved body composition with similar effects on strength and aerobic capacity.
authors.affiliation: Division of Health Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, Australia.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Wycherley
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Buckley
authors.forename: Manny
authors.initials: M
authors.lastname: Noakes
authors.forename: Peter M
authors.initials: PM
authors.lastname: Clifton
authors.forename: Grant D
authors.initials: GD
authors.lastname: Brinkworth
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D001823:Body Composition; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D008076:Cholesterol, HDL; D004032:Diet; D018752:Diet, Fat-Restricted; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy*; D050177:Overweight / Q000178:diet therapy*; D010101:Oxygen Consumption / Q000502:physiology*; D014280:Triglycerides / Q000097:blood; D015431:Weight Loss; D055815:Young Adult
chemical_list: D008076:Cholesterol, HDL; D004044:Dietary Proteins; D014280:Triglycerides