Final answer:
Obesity is defined as having a BMI greater than 30 kg/m² and can lead to various serious health conditions.
Step-by-step explanation:
Obesity is defined by the body mass index (BMI), which is a measure of a person's weight in kilograms divided by height in meters squared. The normal, or healthy, BMI range is between 18 and 24.9 kg/m². Overweight is defined as a BMI of 25 to 29.9 kg/m², and obesity is considered to be a BMI greater than 30 kg/m². Severe obesity or long-term obesity can result in serious medical conditions, including coronary heart disease, type 2 diabetes, cancer, hypertension, stroke, liver disease, gall bladder disease, sleep apnea, osteoarthritis, and infertility.