CLASSIFICATIONS OF OBESITY, OVERWEIGHT, AND UNDERWEIGHT FOR ADULTS
Classifications of obesity, overweight, and underweight are different for adults than for children and teens. For adults, obesity, overweight, and underweight categories are defined by fixed BMI cut points derived from morbidity and mortality data. Among adults, underweight and obesity, particularly higher levels of obesity, are associated with higher relative mortality risk compared with healthy weight (Flegal et al., 2013; Flegal et al., 2005). For adults, BMI is not age-or sex-specific as it is for children and teens.
Clinical guidelines for adult BMI classifications were established in 1998 by the National Heart, Lung, and Blood Institute in cooperation with The National Institute of Diabetes and Digestive and Kidney Disease (www.nhlbi.nih.gov/guidelines/obesity/index.htm) and are as follows: