For adults, BMI categories are underweight, healthy weight, overweight, and obesity. Obesity is further subdivided into three classes. BMI is a screening measure.

Understanding the Context

BMI should be considered with other factors when assessing an individual's health. Obesity is a medical condition classified by body mass index (BMI) with three distinct levels of severity: class 1 (BMI 30-34.9), class 2 (BMI 35-39.9), and class 3 (BMI 40 or higher). What Are the Classes of Obesity? Class 1, Class 2, and Class 3 ...

Key Insights

There are three general classes of obesity that providers use to decide what steps you can take to lose weight. Those classes are: Class 1 obesity: BMI 30 to less than 35 kg/m² (kilograms per square meter). Class 2 obesity: BMI 35 to less than 40 kg/m². Class III obesity: BMI 40+ kg/m². Obesity classes are based on body mass index (BMI) and gauge the risk of health issues.

Final Thoughts

Class 1 obesity starts at a BMI of 30, while Class 3 obesity has a BMI of 40 or higher. Making lifestyle changes can help prevent and manage obesity and its risks. Obesity is often defined as having a body mass index (BMI) of 30 or higher. However, there are actually three different classes of obesity, and they’re organized according to severity. Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. [1]: 6 The World Health Organization (WHO) classifies obesity by body mass index (BMI).

Learn how doctors categorize obesity into classes using BMI, as well as related health risks and treatments based on the obesity grading system. Obesity is classified into three stages based on body mass index (BMI): Class 1 (BMI 30 to 34.9), Class 2 (BMI 35 to 39.9), and Class 3 (BMI 40 or higher). These are the most widely used categories, established by the CDC and WHO. Class III obesity, formerly known as morbid obesity, is a complex chronic condition that can lead to several serious health issues.