For most of my life, I was a pretty chunky kid. Last summer however, I started an intense exercise program, and lost about 30 pounds. My family was actually a little worried about me, as it seemed I may have lost to much weight. Right now I'm about 6 foot, 165 pounds. In other words I'm pretty dang thin.
Lately I've really been slacking off on the exercise, I don't run much anymore, and I hardly lift. I'm afraid that I am going to get fat again. My brother tells me that my metabolism has probably kicked in, and that I could eat a ton and not gain anything (he is of similar height and weight, and has a very fast metabolism).
Should I be so worried about gaining my weight back? Or can I afford to slack off?