I was one of those gifted people, I could eat anything in any amount and I always stayed lean. I didn't go to a gym, I just work physical jobs, played sports, rode a bike to get to work, walked and hiked a lot.
But it caught up with me, big time and in the last 5 years I have had to learn I cannot eat anything I want and the horrible eating habits I developed when I was younger are proving very difficult to break.
I do great for 1 - 4 weeks, then fall flat on my face for a week or two, then repeat the cycle all over again.
I have learned that the most important thing for diet and exercise, is consistency, day after day, month after month, just simply stick to it and eventually you will get results.
So simple and yet so difficult.