title: Effect of acute caloric restriction on work efficiency.
abstract: Whether caloric restriction can alter the efficiency of muscular work raises important questions regarding the control of energetic coupling processes and the efficacy of exercise as a treatment for obesity. To address these issues, oxygen uptake (VO2) was determined at rest and during incremental cycle ergometry in 13 moderately obese (133 +/- 3% ideal body weight, means +/- SEM) women during weight maintenance and after 3 wk of caloric restriction (800 kcal/d). Work efficiency was calculated from the linear portion of the VO2-work rate relationship. Caloric restriction decreased body weight 4.0 +/- 0.4 kg (p less than 0.05), VO2 at rest 32 +/- 3 mL/min (p less than 0.05), and VO2 during unloaded (0 W) cycling 47 +/- 14 mL/min (p less than 0.05). However, work efficiency was unchanged (ie, -0.3 +/- 1.2%, NS). We conclude that, despite metabolic adaptations resulting in decreased energy expenditure at rest and during zero Watt cycling, acute caloric restriction does not alter work efficiency.
authors.affiliation: Department of Medicine, School of Medicine, University of California, Los Angeles.
authors.forename: D C
authors.initials: DC
authors.lastname: Poole
authors.forename: L C
authors.initials: LC
authors.lastname: Henson
mesh_terms: D000328:Adult; D004038:Diet, Reducing; D004526:Efficiency / Q000502:physiology*; D002149:Energy Intake; D004734:Energy Metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D009765:Obesity / Q000178:diet therapy / Q000503:physiopathology; D010101:Oxygen Consumption; D005082:Physical Exertion; D013997:Time Factors