Final answer:
Obesity is measured by BMI, with Class 2 (obese 2) defined as a BMI of 35-39.9 and Class 3 (obese 3) as a BMI of 40 or higher. These obesity levels carry a high risk of numerous health issues, but weight loss can mitigate these risks.
Step-by-step explanation:
Obesity is diagnosed using the body mass index (BMI), which calculates the ratio of weight to height. An obese 2 BMI, also known as Class 2 obesity, is a BMI between 35 to 39.9 kg/m². An obese 3 BMI, referred to as Class 3 or severe obesity, is a BMI of 40 kg/m² or higher. These obesity classes significantly increase the risk of health conditions such as coronary heart disease, type 2 diabetes, various cancers, hypertension, dyslipidemia, stroke, liver disease, gallbladder disease, sleep apnea, osteoarthritis, and infertility. Losing weight has been shown to reduce the risk or help manage these conditions.