BMI is just too vague. I was a chubby fat bastard when I was 17, I think at my heaviest I was 11stone 7lbs at 5' 10. Problem is that I didn't do any sports or exercise, so all that weight was just fat, no muscle. Checked it online and that was a BMI of 23!! Bodyfat measurement needs to become a regular thing. Gyms should all have accurate measurers, they should have them in schools, doctors should regularly check it since it only takes a few seconds. I had no idea back then.