The study, published in the Journal of Clinical Endocrinology and Metabolism, the Universities of Bath and Birmingham found that by changing the timing of when you eat and exercise, one can better control the blood sugar levels.
“We found that the men in the study who exercised before breakfast burned double the amount of fat than the group who exercised after,” said study author Javier Gonzalez from the University of Bath.
“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,” Gonzalez said.
The six-week study, which involved 30 men classified as obese or overweight and compared results from two intervention groups (who ate breakfast before/after exercise) and a control group (who made no lifestyle changes), found that people who performed exercise before breakfast burned double the amount of fat than the group who exercised after breakfast.
They found that increased fat use is mainly due to lower insulin levels during exercise when people have fasted overnight, which means that they can use more of the fat from their fat tissue and the fat within their muscles as a fuel.
While this did not lead to any differences in weight loss over six weeks, it did have ”profound and positive” effects on their health because their bodies were better able to respond to insulin, keeping blood sugar levels under control and potentially lowering the risk of diabetes and heart disease.
The research team also wanted to focus on the impact on the fat stores in muscles for individuals who either worked out before or after eating and the effect this had on insulin response to feeding.
Over the six-week trial, the research team found that the muscles from the group who exercised before breakfast were more responsive to insulin compared to the group who exercised after breakfast, in spite of identical training sessions and matched food intake.
The muscles from those who exercised before breakfast also showed greater increases in key proteins, specifically those involved in transporting glucose from the bloodstream to the muscles.
For the insulin response to feeding after the six-week study, remarkably, the group who exercised after breakfast were in fact no better than the control group, the study said.