May also be called: Morbid Obesity; Severe Obesity

Morbid obesity is severe obesity that's generally defined as a body mass index (BMI) greater than or equal to 40. BMI uses height and weight measurements to estimate body fat.

More to Know

A number of factors contribute to becoming overweight. Genetics, lifestyle habits, or a combination of both may be involved. In some instances, endocrine (hormone) problems, genetic syndromes, and medications can be associated with excessive weight gain.

Obesity in kids is almost always influenced by lifestyle factors — such as drinking sugar-sweetened beverages; eating fatty, processed foods; not getting enough sleep; and spending too much time being sedentary (watching TV, playing with electronic devices, etc.) instead of being physically active.

Morbid obesity can greatly increase a person's risk of numerous medical problems, including type 2 diabetes, high blood pressure, high cholesterol, bone and joint problems, asthma, sleep apnea, liver and gallbladder disease, heart disease, and depression and other mental health issues.

Morbid obesity is best treated through lifestyle changes, such as eating a healthier diet, getting more exercise, and, sometimes, working with professionals who can help with this problem. When lifestyle changes alone aren't effective, surgery may be done to decrease the risk of other health issues.

Keep in Mind

Changing habits and losing weight can be very difficult, but it is possible. Even morbidly obese people can achieve a healthy weight if they eat well, exercise regularly, and incorporate healthy habits into their daily lives. By doing so, they will greatly decrease their risk of obesity-related health problems and emotional issues.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.