Fasting before exercise increased the expression of genes in adipose tissue that signify that stored fat is being used to fuel metabolism in overweight men but eating a meal 2 hours before did not. There was also greater fat oxidation (burning of fat) during exercise in the fasted state.
One potential caveat is the meal was composed of refined carbohydrates and sugars (ie. cornflakes, bread with jam). It would be interesting to see if the same results hold true for either a high-fat meal or a meal rich in fiber (ie. vegetables). The question is…is it the food type or just the signaling pathways that feeding, in general, activates despite food type that is inhibiting the activation of these genes in adipose tissue.
Maybe this is another reason why people like intermittent fasting. A lot of people workout while fasting rather than during their eating window.