A low-glycemic diet lifestyle intervention improves fat utilization during exercise in older obese humans

Thomas P J Solomon, Jacob M Haus, Marc A Cook, Chris A Flask, John P Kirwan

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


OBJECTIVE: To determine the influence of dietary glycemic index on exercise training-induced adaptations in substrate oxidation in obesity.

DESIGN AND METHODS: Twenty older, obese individuals undertook 3 months of fully supervised aerobic exercise and were randomized to low- (LoGIX) or high-glycemic (HiGIX) diets. Changes in indirect calorimetry (VO2 ; VCO2 ) were assessed at rest, during a hyperinsulinemic-euglycemic clamp, and during submaximal exercise (walking: 65% VO2 max, 200 kcal energy expenditure). Intramyocellular lipid (IMCL) was measured by (1) H-magnetic resonance spectroscopy.

RESULTS: Weight loss (-8.6 ± 1.1%) and improvements (P < 0.05) in VO2 max, glycemic control, fasting lipemia, and metabolic flexibility were similar for both LoGIX and HiGIX groups. During submaximal exercise, energy expenditure was higher following the intervention (P < 0.01) in both groups. Respiratory exchange ratio during exercise was unchanged in the LoGIX group but increased in the HiGIX group (P < 0.05). However, fat oxidation during exercise expressed in relation to changes in body weight was increased in the LoGIX group (+10.6 ± 3.6%; P < 0.05). Fasting IMCL was unchanged, however, extramyocellular lipid was reduced (P < 0.05) after LoGIX.

CONCLUSIONS: A LoGIX/exercise weight-loss intervention increased fat utilization during exercise independent of changes in energy expenditure. This highlights the potential therapeutic value of low-glycemic foods for reversing metabolic defects in obesity.

Original languageEnglish
Pages (from-to)2272-8
Number of pages7
Issue number11
Publication statusPublished - Nov 2013

Bibliographical note

Copyright © 2013 The Obesity Society.


  • Adipose Tissue
  • Aged
  • Aging
  • Diet, Carbohydrate-Restricted
  • Exercise
  • Exercise Therapy
  • Female
  • Glycemic Index
  • Humans
  • Life Style
  • Lipid Metabolism
  • Male
  • Middle Aged
  • Obesity
  • Weight Reduction Programs


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