Whether or not to eat before training is one of the big debates in the fitness world. Now, new research from the Universities of Bath and Birmingham suggests exercising before breakfast may come with a number of health benefits.
In a small study published in the Journal of Clinical Endocrinology and Metabolism, researchers found that people who trained before breakfast burned more fat than those who exercised after breakfast, it also improved how their bodies responded to insulin, keeping blood sugar levels under control, potentially reducing the risk of developing type 2 diabetes and cardiovascular disease.
A group of 30 overweight men were split into two groups, one of which ate breakfast before performing a cycling session, with the other groupe eating after the exercise. They found that the group who trained on an empty stomach burned double the amount of fat than the other group because they had lower insulin levels having fasted overnight, which allowed them to tap into their fat reserves for fuel.
Interestingly, this didn't result in any differences in weight loss between the two groups in the six-week period, but it did have 'profound and positive’ effects on their health, the scientists say, because their bodies were better able to respond to insulin, controlling blood sugar levels, which in turn can lower the risk of diabetes and heart disease.
Dr Javier Gonzalez, of the Department for Health at the University of Bath, said: "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."
The scientists acknowledge that they now need to test the the theory with female respondents.
Co-author, Dr Gareth Wallis of the University of Birmingham, added: "This work suggests that performing exercise in the overnight-fasted state can increase the health benefits of exercise for individuals, without changing the intensity, duration or perception of their effort. We now need to explore the longer-term effects of this type of exercise and whether women benefit in the same way as men."
So incorporating fasted training into your workout regime may have some health benefits, but ultimately it's about what works best for you. If you choose to do so it's crucial to refuel properly afterwards as exercise depletes your glycogen stores. A high-protein meal is the best way to refuel after exercising as it'll help to repair your muscles, enabling you to go harder in your next session.