Exercise is recommended for people who are overweight or obese as a way to reduce their risk of developing type 2 diabetes and cardiovascular disease. But people don't always have time to exercise as much as they would like, so finding ways to increase the health benefits of exercise is important.
Our latest research has found a way to do just that, and it's to do with timing. This means you might be able to get away with doing less exercise if other commitments, such as family and work, always seem to get in the way.
One of the main health benefits of exercise is that it improves our response to insulin and we can better control our blood sugar levels – even if we don't see this change happening. It is now becoming clear that when we eat in relation to exercise could be important for this insulin response.
Our study looked at the responses to six weeks of exercise, which was supervised cycling for 50 minutes, three times a week. In one group, overweight or obese men exercised before breakfast (fasted state) and showed an improved insulin response after the training. That is, they had to produce less insulin to control their blood sugar levels.
This suggests that they had a lower risk of diseases such as type 2 diabetes after the training. But the men who performed the same exercise after eating breakfast did not show an improved blood insulin response.
The men who exercised before breakfast also burned about double the amount of fat during exercise than the group who exercised after breakfast. Current evidence suggests that this increased fat burning during exercise may explain why that group showed improved health benefits.