Class 2 obesity is a category of obesity defined by a Body Mass Index (BMI) of 35 to less than 40. BMI is a screening tool that estimates the level of body fat based on a persons height and weight. Obesity is frequently divided into three categories: class 1, class 2, and class 3, with class 3 being the most severe. Class 3 obesity is also referred to as "severe" obesity. People with class 2 obesity have a moderate risk of developing obesity-related health problems. These health problems include high blood glucose or diabetes, high blood pressure, high blood cholesterol and triglycerides, heart attacks due to coronary heart disease, heart failure, stroke, and bone and joint problems.