Related Experiment Video
Updated: Feb 10, 2026

A Chronic High-Intensity Interval Training and Diet-Induced Obesity Model to Maximize Exercise Effort and Induce Physiologic Changes in Rats
Published on: April 28, 2023
Carbohydrate intake reduces fat oxidation during exercise in obese boys
Lisa Chu1, Michael C Riddell, Tim Takken
1Children's Exercise and Nutrition Centre, McMaster University, Children's Hospital, Chedoke Hospital, Evel Bldg, Room 469, Sanatorium Road, P.O. Box 2000, Hamilton, ON, L8N 3Z5, Canada.
Abstract:
The recent surge in childhood obesity has renewed interest in studying exercise as a therapeutic means of metabolizing fat. However, carbohydrate (CHO) intake attenuates whole body fat oxidation during exercise in healthy children and may suppress fat metabolism in obese youth. To determine the impact of CHO intake on substrate utilization during submaximal exercise in obese boys, seven obese boys (mean age: 11.4 ± 1.0 year; % body fat: 35.8 ± 3.9%) performed 60 min of exercise at an intensity that approximated maximal fat oxidation. A CHO drink (CARB) or a placebo drink (CONT) was consumed in a double-blinded, counterbalanced manner. Rates of total fat, total CHO, and exogenous CHO (CHO(exo)) oxidation were calculated for the last 20 min of exercise. During CONT, fat oxidation rate was 3.9 ± 2.4 mg × kg fat-free mass (FFM)(-1 )× min(-1), representing 43.1 ± 22.9% of total energy expenditure (EE). During CARB, fat oxidation was lowered (p = 0.02) to 1.7 ± 0.6 mg × kg FFM(-1 )× min(-1), contributing to 19.8 ± 4.9% EE. Total CHO oxidation rate was 17.2 ± 3.1 mg × kg FFM(-1 )× min(-1) and 13.2 ± 6.1 mg × kg FFM(-1) × min(-1) during CARB and CONT, respectively (p = 0.06). In CARB, CHO(exo) oxidation contributed to 23.3 ± 4.2% of total EE. CHO intake markedly suppresses fat oxidation during exercise in obese boys.
More Related Videos
13:09Rapid Model to Evaluate the Anti-Obesity Potential of a Combination of Syzygium aromaticum Clove and Cuminun cyminum Cumin on C57BL6/j Mice Fed High-Fat Diet
Published on: July 31, 2021
13:09Segmentation and Measurement of Fat Volumes in Murine Obesity Models Using X-ray Computed Tomography
Published on: April 4, 2012
Related Concept Videos
Redox Titration: Other Oxidizing and Reducing Agents
What are Carbohydrates?
Chemistry of Carbohydrates
Carbohydrate Digestion
Obesity
Oxidation Numbers