I do think there is a lot more to what someone weighs than what they eat and how active they are. And it's SO unfair.

Example: my son has this incredible metabolism. He eats, I'm not EVEN exagarating, more than the rest of the family combined. He eats all day long, whatever quanity, whatever calorie content he wants. He must consume 10,000 calories a day! And, frankly, he sits on his butt a lot. He plays a lot of video games, watches TV, etc. He is 5' 10" and weighs 160 pounds, quite thin.

My step-son, OTOH, eats an average amount for a teenage boy, I'd say, but less than my son, for sure. He is a little more active, too, riding his bike around more, etc. He is 5' 1" and weighs 150 pounds, quite heavy.

My niece and I were always the same way growing up. We are about the same height, but she always weighed at least 20 pounds less than I did, yet ate easily twice as much as me a day, every day. No fair!