I disagree with those who believe that one needs to eat before exercising. I never did, and have always been very sporty. Eating takes away energy (unless you eat like a birdie). The fuller is my stomach, the duller I feel, in all respects, from mental to physical. My fasting days is when I accomplish the most in a best mood and highest levels of energy.
I agree with this 100%, you cannot do heavy exercises with full stomach, besides it's stupid you could hurt yourself. Have seen a knight or samurai going to battle after meal? it's easy to blow off your guts when they're full. NEVER go to war with full stomach.