For me, it's a conscious decision. I gained some weight very quickly (junk eating and no exercise) and took a good long look in the mirror and said "enough is enough". For me, that put my head in the right place to sit down and plan my attack; what to eat, what not to eat, how to do it, how to exercise, and most importantly, I set my goals realistically. I also went to my local GP and requested full blood tests to see my starting point with cholesterol, triglycerides, etc, so I could compare as time went along. So I suppose I just got very serious about it.