If you have trained your body to expect food every 5 hours, sure. If humans could not survive short (letalone prolonged) periods of fasting, we would not have survived very long.

How are you supposed to hunt an animal if you get light headed and lose mental faculties when hungry?

Not really no. Our bodies have not evolved since the point in time where the access to food was much more difficult, it is perfectly adapted to not getting energy intake regularly.

That's just not true.

I can run much farther if I ate my previous meal than if I didn't.

And the effects of skipping breakfast on the cognition of children have been studied ad nauseam. A lengthy list: http://frac.org/wp-content/uploads/2009/09/breakfastforlearn...

> I can run much farther if I ate my previous meal than if I didn't

If anything I would think the reverse to be true. Runners and cyclists eat sugar gels instead of 'real food' because gels are easier to digest, and all the energy you spend on digestion isn't spent on the activity.

They generally only do that during activities or shortly (30-60 minutes) before. Gels are eaten rather than "real" foods to match the glycemic index to the rate of energy expenditure.

In any case, this really only applies to lengthy activities, where glycogen is exhausted. It doesn't matter for a 5k or even a 10k run.

Depends on what your body is accustomed to.