There are studies that support exercising in a fasted state, more medical advice points to consuming smart, nutritious snacks before you hit the gym to enhance your performance. Exercising on an empty stomach can lead the digestive system to break down muscle tissue, which isn’t helpful if you’re training to get stronger, faster or lose weight. . . The closer you get to exercise time, the simpler your choices need to be in order to help your body utilize energy more efficiently. If you can eat 2-3 hours prior to exercise, a large meal with complex carbs will have time to be absorbed and processed. But, if you need to eat closer to your workout (within about an hour, or so), it’s best to choose a simpler snack.