No. It's all in the age. If you are 12-14 and haven't hit puberty yet your good.. Your body will change,, you may not come out with a six pack but you will not become obese.. Unless you do nothing at all
I am ten and I weigh 137 lbs. Just try and keep off the junk food and exercise. Just be careful not to over do it. Wouldn't be good to starve yourself either:)