No, I disagree. If that was the case nothing in our body would age and slow down. I don't agree. Being active helps alot, but just like when you were younger you can be a pig and not gain a pound when you haven't been active in awhile. It changes, just like everything else in your body does. That polyp in you that was found, that case of shingles you developed, that knee that went bad on you, etc..., the body changes with age. Everyones metabolic rate and thyroid is different. Many have to battle their whole life and excercise hardcore, and some just barely have to do anything. It's all genetics mostly.