I agree...... my friend Michael, 13, is about 5'6 and weighs like 140 that is most certainly not overweight. He is loosing weight anyway and would like to be 120 lbs. I keep telling him that hes not fat and hes gonna have problems if he has a dramatic weight loss becasue he is not eating very much. He is growing fast like me and im worried that he might have growing prolems if he looses while he quickly grows. Im 5'6 151 and i am not loosing becasue my Dr says not to. He says i need to gain as i grow. I have grwoing pains too and he sadi hed be worried about me if i was like 20 lbs lighter. I need to convionce my friend that he needs to gain as he grows and not loose and lead to health problems like you just said.