Large-scale American and European studies have found that mortality risk is lowest at a BMI of 20–25 kg/m2 in non-smokers and at 24–27 kg/m2 in current smokers, with risk increasing along with changes in either direction.
Debelosti pri otrocih in mladostnikih se ne določa v absolutnem smislu, temveč glede na zgodovinsko normalno skupino, tako da se jo jemlje kot ITM nad 95. percentilom.