I know a few people that are very fit but as you say, they are not healthy at all. One guy I know who has a very restrictive diet is constantly coming down with something and is always in the hospital for this and that. He never really looks at the fact that it very well could be his diet that is causing this. He tries, and succeeds at maintaining a very low body fat percentage but he always feels down in the dumps and has medical issues constantly. I'm not saying my diet of beer and meat mixed with a vegetable every now and then is better, but yeah, fit and healthy are not the same thing at all.