Researchers found increasing walking speed did not cause fat oxidation, otherwise known as "fat burning," to speed up among a group of overweight boys between the ages of 9 and 11.
Instead, the study showed that the highest fat and carbohydrate burning occurred at a walking speed of about 2.5 miles per hour.
Walk Slow, Burn Fat
In the study, researchers compared fat burning rates at different walking speeds among 24 overweight boys with an average body mass index (BMI, a measure of weight in relation to height) of 25.5. A BMI over 25 is considered overweight and a BMI over 30 is considered obese.
The results appear in the January issue of The Journal of Clinical Endocrinology & Metabolism.
The maximum fat burning rate was found at a moderate walking speed of about 2.5 miles per hour (4 kilometers/hour). Increasing the walking speed to 5 kilometers/hour or 6 kilometers/hour did not substantially increase the fat burning rate.
Although the boys burned more carbohydrates when they increased their walking speed, researchers found the moderate walking pace promoted the highest fat to carbohydrate burning ratio, which is recommended for weight loss.
Researchers say that obesity causes the body to get energy from other sources rather than fat, which causes fat to build up. But exercise stimulates fat burning and helps promote weight loss.
Based on these results, researchers say it may be more reasonable to prescribe and encourage low-intensity exercise, which is more feasible and acceptable to obese children, than to insist on more intense exercise programs that may not provide any additional fat-burning benefits.