Should You Eat Before You Exercise?

You can eat before a workout, but the key is timing. If you eat a large meal right before exercising, your body slows digestion as energy is sent to your muscles for your workout. Sometimes the result is cramping and an upset stomach. An easy workout like a moderate walk will not have the same effect, so the easier the workout, the safer it is to eat a meal beforehand. 
(Exercise.com)