title: Effects of carbohydrate quantity and glycemic index on resting metabolic rate and body composition during weight loss.
abstract: OBJECTIVE
  To examine the effects of diets varying in carbohydrate and glycemic index (GI) on changes in body composition, resting metabolic rate (RMR), and metabolic adaptation during and after weight loss.
  
  
  METHODS
  Adults with obesity (n = 91) were randomized to one of four provided-food diets for 17 weeks. Diets differed in percentage energy from carbohydrate (55% or 70%) and GI (low or high) but were matched for protein, fiber, and energy. Body weight, body composition, RMR, and metabolic adaptation (measured RMR-predicted RMR) were measured during weight loss and subsequent weight stability.
  
  
  RESULTS
  No effect of dietary carbohydrate content or GI on body weight loss or percentage of weight lost as fat mass (FM) was observed. Measured RMR was significantly lower (-226 kJ/day [95% CI: -314 to -138 kJ/day], P < 0.001) than predicted RMR following weight loss, but this difference was attenuated after 5 weeks of weight stability. Metabolic adaptation did not differ by dietary carbohydrate content or GI and was not associated with weight regain 12 months later.
  
  
  CONCLUSIONS
  Moderate-carbohydrate and low-GI diets did not preferentially reduce FM, preserve lean mass, or attenuate metabolic adaptation during weight loss compared to high-carbohydrate and high-GI diets.
authors.affiliation: Obesity and Energetics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: J Philip
authors.initials: JP
authors.lastname: Karl
authors.affiliation: Obesity and Energetics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
authors.affiliation: Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Schaefer
authors.affiliation: Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Joi A
authors.initials: JA
authors.lastname: Gleason
authors.affiliation: Obesity and Energetics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Fuss
authors.affiliation: Metabolic Research Unit, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Helen
authors.initials: H
authors.lastname: Rasmussen
authors.affiliation: Obesity and Energetics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Saltzman
authors.affiliation: Obesity and Energetics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA.
authors.forename: Sai Krupa
authors.initials: SK
authors.lastname: Das
mesh_terms: D000368:Aged; D001481:Basal Metabolism / Q000187:drug effects; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D005260:Female; D038321:Glycemic Index / Q000502:physiology*; D000067940:Glycemic Load / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism*; D015431:Weight Loss / Q000187:drug effects
chemical_list: D004040:Dietary Carbohydrates