Researchers conducted a six week study involving thirty male participants classified either as obese or overweight, and compared the results from two groups those who ate breakfast before exercise, and those who ate after. The study also involved a control group of participants who made no lifestyle changes.
The increased fat use is due to lower insulin levels during exercise when people have fasted overnight, indicating that they can use more of the fat from their fat tissue and the fat within their muscles as a fuel, the researchers said.
While the six week study did not lead to any significant weight loss in the participants, the researchers added that it did have "profound and positive" effects on their health since 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. According to the researchers, the muscles from those who exercised before breakfast showed more increase in key proteins, specifically those involved in transporting glucose from the bloodstream to the muscles.