NonObese

Nonobese is a descriptive term for individuals who do not meet the clinical criteria for obesity. In most health contexts, obesity is defined by a body mass index (BMI) of 30 kg/m2 or higher. Accordingly, nonobese includes people with BMI below 30, encompassing underweight, normal weight, and overweight categories that do not reach the obesity threshold. The term is primarily used in research and clinical discussions to separate those not classified as obese from those who are.

Because BMI is a simple proxy for body fatness, nonobese status does not guarantee low health risk. BMI does not distinguish fat from lean mass or account for fat distribution. Some people with a normal or overweight BMI may have high visceral fat or low muscle mass, a situation described as normal-weight obesity or metabolically obese normal weight, which can accompany insulin resistance, dyslipidemia, or hypertension even in the absence of obesity on BMI criteria.

Health implications also depend on age, sex, ethnicity, and comorbid conditions. Nonobese populations show wide variation in metabolic risk profiles, and lifestyle factors such as diet, physical activity, and smoking can influence risk independently of BMI category. In epidemiology, separating nonobese and obese groups helps study disease risk independent of obesity, but relying solely on BMI can obscure important health differences.

See also obesity, BMI, metabolic syndrome, normal-weight obesity.