Surprisingly, you can and should eat before, during and after depending on your needs. The key is you want to fuel yourself, but not over fuel. Never enter a workout hungry. You will be unable to sustain the energy to do well and your body will hoard fat. Try a sports drink, energy gel or exercise bar. Before a really tough work out it’s good to have a little carbs like pasta, juice, fruit or bread. It’s usually best to avoid high fiber right before a workout. During a workout, if you feel energy waning having a sports drink, bar or gel handy will help. After your workout, it’s best to mix carbs and protein to rebuild muscle since your insulin is at it’s highest level just after a workout. The only problem is you have a 45 minute window after a workout when it is the best time to eat to properly refuel your body and keep it at it’s peak. So it might be best to eat somewhere near the gym or keep food with you if you know you’ll be working out that day.