Long–Term Effects of Energy-Restricted Diets Differing in Glycemic Load on Metabolic Adaptation and Body Composition*

Sai Krupa Das*, 1, Cheryl H. Gilhooly1, Julie K. Golden1, Anastassios G. Pittas2, Paul J. Fuss1, Gerard E. Dallal1, Megan A. McCrory3, Edward Saltzman1, Susan B. Roberts1
1 Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
2 Tufts - New England Medical Center Hospital, Boston, MA, USA
3 Department of Food and Nutrition, Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA

© 2008 Das et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Energy Metabolism Laboratory, Room 1314A, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington St., Boston, MA 02111, USA; Tel: 617-556-3313; Fax: 617-556-3033;


A randomized controlled trial of high glycemic load (HG) and low glycemic load (LG) diets with food provided for 6 months and self-administered for 6 additional months at 30% caloric restriction (CR) was performed in 29 overweight adults (mean±SD, age 35±5y; BMI 27.5±1.5 kg/m). Total energy expenditure (TEE), resting metabolic rate (RMR), fat and fat free mass (FFM), were measured at 3, 6 and 12 months. Changes in TEE, but not changes in RMR, were greater than accounted for by the loss of FFM and fat mass (P=0.001-0.013) suggesting an adaptive response to long-term CR. There was no significant effect of diet group on change in RMR or TEE. However, in subjects who lost >5% body weight (n=26), the LG diet group had a higher percentage of weight loss as fat than the HG group (p<0.05), a finding that may have implications for dietary recommendations during weight reduction.

Keywords: Glycemic load, caloric restriction, body weight, metabolic rate.