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What is super morbidly obese?

By Ruben J. Rucoba, MD Nov 17, 2021 • 5 min

Approximately 4 in every 10 adults in the U.S. are obese, according to the Centers for Disease Control and Prevention (CDC).

There are several different levels of obesity, and the risk of certain health problems can rise as the level of obesity increases, so it can be helpful to know about these obesity classifications. Let's learn more about the different subgroups of obesity and their health risks, including what it means to be super morbidly obese.

Classifications of obesity

Obesity in adults has been defined and divided into subgroups by the National Institutes of Health (NIH) using body mass index (BMI). The BMI is calculated by dividing the body weight, in kilograms, by the height, in meters, squared. For example, a person with a body weight of 80 kg and 1.76 m height has a BMI of 25.8 kg/m² (calculated from 80 divided by 1.76 and divided again by 1.76).

BMI is only a rough estimate of obesity, but it's a quick way to get an idea of a person's weight compared to height. The NIH groups people by BMI into different ranges:

  • Underweight: BMI under 18.5
  • Normal weight: BMI of 18.5–24.9
  • Overweight: BMI of 25.0–29.9
  • Obesity Class I (obese): BMI of 30.0–34.9
  • Obesity Class II (severe obesity): BMI of 35.0–39.9
  • Obesity Class III (extreme obesity, formerly referred to as morbid obesity): BMI of 40.0 or higher

Researchers often further divide Class III, adding two more categories to indicate higher levels of extreme obesity. Terms used for these levels may vary. For example, "super morbid obesity" is sometimes just referred to as "super obesity."

  • Super morbid obesity: BMI of 50.0 or higher
  • Super-super morbid obesity: BMI of 60 or higher

How does super morbid obesity differ from the other types of obesity?

A person who has super morbid obesity has a BMI of 50 or higher, nearly twice the BMI level of someone who is classified as overweight. A BMI of 30 or higher is considered obese. Obesity is often divided into three categories—Class I, Class II and Class III—with Class III including all BMIs of 40 or greater. Super morbid obesity falls into obesity Class III.

Studies have demonstrated that increasing levels of obesity put people at greater risk of negative health effects:

  • A scientific report looking into numerous research studies found that a BMI of 35 or greater, severe or morbid obesity, was associated with higher all-cause mortality.
  • The incidence of obesity hypoventilation syndrome (a dangerous condition involving disordered breathing that leads to too much carbon dioxide and too little oxygen in the blood) is 8% to 12% in people who are obese, but up to 50% in the super morbidly obese.
  • Compared with pregnant women with Class I obesity, those who are super morbidly obese have a higher risk of pregnancy complications, including diabetes and high blood pressure.
  • While in an intensive care unit (ICU), super morbidly obese people are more likely than those with obesity to need noninvasive ventilation and to have a longer stay in the ICU.
  • Compared with all other obesity levels (normal, obese and morbidly obese), super morbid obesity results in a significantly higher number of complications after total hip replacement surgery, including blood clots, the need for blood transfusion, hip dislocation, infection, readmission and revision surgery.
  • One study found that people with super-super morbid obesity (BMI of 60 or greater) resulted in more complications following bariatric surgery than super morbid obesity.

What treatment is there for super morbid obesity?

For people with super morbid obesity, treatment is usually multipronged. The various treatments available include healthy eating plans, regular physical activity, weight management programs, behavior modification, bariatric surgery, medications and weight loss devices.

One example of a weight loss device is a gastric balloon system in which water balloons are inserted into the stomach to make you feel fuller and eat less.

We've seen how the different levels of obesity can affect health. The good news is there's always something that can be done. If you're worried about being in the morbidly or super morbidly obese range, talk to your healthcare provider about how to lower your weight and enjoy a healthier life.

Published November 2021.