Classification of adults according to BMI
| Classification | BMI | Risk of comorbidities |
|---|---|---|
| ?Underweight | ?<18.5 | ?Low (but risk of other clinical problems increased)? |
| ?Normal range | ?18.50-24.99 | ?Average |
| ?Asia-normal range? | ?18.5-22.9 | ?Average |
| ?Overweight | ?≥25.00 | |
| ?Pre-obese | ?25.00-29.99? | ?Increased |
| ?Asia-overweight | ?23-24.9 | |
| ?Obese class I | ?30.00-34.99 | ?Moderate |
| ?Asia-obese class I | ?25-29.9 | |
| ?Obese class II | ?35.00-39.99 | ?Severe |
| ?Asia-class II | ?≥30.00 | |
| ?Obese class Ill | ?≥40.00 | ?Very severe |
These BMI values are age-independent and the same for both sexes. However, BMI may not correspond to the same degree of fatness in different populations due, in part, to differences in body proportions. The table shows a simplistic relationship between BMI and the risk of comorbidity, which can be affected by a range of factors, including the nature of an individual’s diet, ethnic group and activity level. The risks associated with increasing BMI are continuous and graded and begin at a BMI above 25. The interpretation of BMI gradings in relation to risk may vary for different populations. Both BMI and a measure of fat distribution (waist circumference or waist-hip ratio) are important in calculating the risk of obesity-related comorbidities.