Effects of carbohydrate quantity and glycemic index on resting metabolic rate and body composition during weight loss

Obesity (Silver Spring). 2015 Nov;23(11):2190-8. doi: 10.1002/oby.21268.


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.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Basal Metabolism* / drug effects
  • Body Composition* / drug effects
  • Body Weight / drug effects
  • Diet
  • Dietary Carbohydrates / pharmacology*
  • Female
  • Glycemic Index / physiology*
  • Glycemic Load / physiology*
  • Humans
  • Male
  • Middle Aged
  • Obesity / diet therapy
  • Obesity / metabolism*
  • Weight Loss* / drug effects


  • Dietary Carbohydrates