Cynthia > If humans had to work hard physically to get their food, perhaps we would not be so inclined to overeat.   

I really like this thought and agree with it wholeheartedly.  But I believe that oftentimes we overestimate the amount of effort it took to get food.  Remembering that men usually did the hunting and women, old men, and children the gathering, hunting was not a daily event generally.  It seems to me that hunters would target big game, but that post olduwan tools it wasn't always extremely difficult to find and kill that game.  But the combination of the hunt and getting the meat back to camp would involve intense but infrequent exercise, maybe two or three times a week.

Gathering, on the other hand, involved repetitive and usually daily activity.

This is the reasoning I've used to justify my two to three times a week of intense activity.  My workouts consist of an intense one mile run followed by weight training two days a week and a 2 mile run with no weights on the third day.  I always allow at least 48 hours between workouts.  Weekly time spent exercising for me is less than two hours.

Jim