Originally Posted by
Raver
Partly genetic and partly environmental. The genetic aspect is basically the speed of one's metabolism and the environmental aspect is whether one has a food addiction or not. A slow metabolism combined with a strong food addiction is basically a recipe for obesity. If one is young and has a fast metabolism then they'll likely remain skinny even if they eat fast foods daily, but will catch up to them when they're middle aged. An individual's metabolism and food addiction can both vary of course from mild to severe. If you have a normal metabolism or slower then it would be wise to exercise at least moderately to maintain or lose your weight and having a good healthy diet is good for anyone even with a fast metabolism. Just because you look skinny on the outside doesn't mean you're healthy on the inside.