It is well-known that exercise is vital for overall health, but a new study is now showing how the time of day may boost the benefits even more. Published in the Journal of Clinical Endocrinology and Metabolism, the study shows that by changing the timing of exercise and eating, it may be easier to control blood sugar levels.
Health scientists at the Universities of Bath and Birmingham conducted the six-week study, which involved thirty men classified as obese or overweight. They compared results from two intervention groups who ate breakfast before exercise, or after exercise, and a control group who made no lifestyle changes. They found that participants who performed exercise before breakfast burned double the amount of fat than the group who exercised after breakfast.
Researchers found that in participants who fasted overnight, there was increased fat use, which is mainly due to lower insulin levels during exercise. This means they were able to use more of the fat from the tissue and the fat within their muscles as fuel.
It was noted that this did not lead to any difference in weight loss over the six weeks, but it did have a profound and positive effect on their health. This was because their bodies were better able to respond to insulin, keeping blood sugar levels under control. This has been found to potentially lower the risk of heart disease and diabetes.
Dr. Javier Gonzalez of the Department for Health at the University of Bath explained: “Our results suggest that changing the timing of when you eat in relation to when you exercise can bring about profound and positive changes to your overall health.
“We found that the men in the study who exercised before breakfast burned double the amount of fat than the group who exercised after. Importantly, whilst this didn’t have any effect on weight loss, it did dramatically improve their overall health.
“The group who exercised before breakfast increased their ability to respond to insulin, which is all the more remarkable given that both exercise groups lost a similar amount of weight and both gained a similar amount of fitness. The only difference was the timing of the food intake.”
Positive Response to Insulin
Over the six weeks of the study, researchers found that the muscles from the group who exercised before breakfast were more responsive to insulin compared to the group who exercised after breakfast. The muscles from participants who exercised before breakfast also showed greater increases in key proteins. This was specifically found in those involved in transporting glucose from the bloodstream to the muscles.
This initial study only involved men, but future research will look to translate these findings for different groups including women. This study does help to show that performing exercise in an overnight-fasted state may be able to increase the health benefits associated with movement. More research needs to be done, but this preliminary study asks the question, if timing can be more important in exercise over intensity or duration.