Working out before breakfast burns twice as much fat as eating first, research suggests. Here’s what happens: Eating carbohydrates causes blood glucose levels to rise, which triggers a release of the hormone insulin. Work out after eating and the body uses the sugar to power your muscles. But exercising in a fasted state forces the body to pull energy from fat instead, explains Javier Gonzalez, a physiologist at the University of Bath in the U.K.
His study, published in The Journal of Clinical Endocrinology & Metabolism, compared one group of overweight men that ate before exercise to one that noshed afterward. While there were no weight changes between the groups — the study only lasted six weeks — the lower insulin levels in the exercise-first group meant that they were burning more fat. Twice as much as the breakfast-first group.
If you’re accustomed to eating first thing, wean yourself off the habit slowly, or have a low-carb breakfast. And when you do eat, maybe skip the buttermilk pancakes and breakfast cereal. Try a lean, strong breakfast, or maybe one rich in amino acids that will help to continue your muscle gains after you exercise. Or make it a protein-rich diet to reduce your cravings for the rest of the day, so you can wake up and do the whole thing again tomorrow.