For adults who are overweight or obese, timing exercise in the morning before breakfast may help them lose a lot more body fat than waiting until after they eat, a recent British study found.
The study examined how exercising before and after eating early in the day affected muscle fat stores and insulin response in a group of 30 overweight men. It was the first to look at this relationship in people with overweight or obesity, according to the researchers.
Participants in the study were divided into three groups: one that ate breakfast before exercising, one that waited until after exercise to eat, and a control group that made no lifestyle changes. Over a six-week period, those who exercised before eating breakfast burned twice as much fat as those who ate first, although the amount of weight lost was similar for both groups. This is because when people fast overnight, they have lower insulin levels during exercise, allowing their body to use more stored fat for energy, said Dr. Javier Gonzalez, of the University of Bath Department for Health.
“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. He added that those who ate breakfast before exercising were no better off in terms of insulin response than members of the control group.