To eat or not
For me right now, because of minimizing my calorie intake to lose weight, I find that if I don't have something light but with protein before I exercise first thing in the morning (I get up at 5:15 am) I will get light headed. Since I am having my larger meal at lunch and a small light meal at dinner, apparently my overnight fast is a bit to much for my body to cope with. However, I usually stick with a slice of toast with light peanut butter and a little honey or half a protein bar. That usually is enough to stop the light headedness but not to heavy as to sit in my stomach.
Based on what everyone has said, it seems that your answer is going to depend on how your body reacts and what it needs.