people who exercise are healthier on average, but i think most of that is due to weight loss.

also people who are stronger have higher life expectancy but i this it is a case of confusing cause and effect - healthy people are strong because they are healthy, not the other way.

if you need to exercise to lose weight ( i do ) then do it.  if you have iron will power and can go hungry 24/7 and have chiseled abs without going to the gym - good for you.