When trying to lose weight, should you eat or fast before exercising?

When trying to lose weight, should you eat or fast before exercising? That’s one of the questions British researchers tried to answer in a recent study by looking at the expression of genes in the fat tissue of a group of overweight males. The expression of the genes PDK4 and HSL increased when the test subjects didn’t eat before exercising, suggesting that energy from stored fat was used to power the physical exercise, potentially leading to weight loss. The opposite was the case when the men ate before exercising.