Clinically severe obesity, which people sometimes call morbid obesity, can increase the risk of a range of other health issues.
For an adult, having clinically severe, or class 3, obesity involves having a body mass index (BMI) of
BMI is not a diagnostic tool, but it can indicate the risk of developing various health issues.
Having severe obesity can make it difficult to do everyday activities, such as walking, breathing, and sleeping. It can also increase the risk of cardiovascular disease, type 2 diabetes, and various other health conditions.
According to the National Institute of Diabetes and Digestive and Kidney Diseases, around
Below, learn more about what clinically severe obesity is and which treatments are available.
When an adult has severe obesity, they have a high percentage of body fat and a BMI of
The following
| BMI | Description |
| Under 18.5 | Underweight |
| 18.5 to less than 25 | Moderate weight |
| 25 to less than 30 | Overweight |
| 30 to less than 35 | Class 1 obesity |
| 35 to less than 40 | Class 2 obesity |
| Above 40 | Class 3 obesity |
Here, find a BMI calculator and more information about BMI.
A person with obesity has a greater risk of heart disease and other conditions. The higher the class of obesity, the greater the likelihood of developing these complications.
However, it is worth noting that a person’s BMI does not necessarily indicate whether they have a healthy weight. It does not reflect the percentage of muscle mass compared with the percentage of fat in the body.
How useful is BMI as a tool for measuring weight and health?
Checking a person’s waist-to-hip ratio and the distribution of fat in their body can give a better idea of their risk of developing complications. Scientists have linked a high waist circumference due to body fat with a
Certain factors can
- Dietary habits and activity levels can affect a person’s levels of energy.
- Socioeconomic conditions can limit access to fresh food and the ability to exercise.
- Genetic factors may play a role.
- Family history may contribute, through both genetic and environmental factors.
- Some medical conditions have links with obesity, including Cushing’s syndrome and polycystic ovary syndrome.
- Stress and anxiety can
increase levels of the hormone cortisol, which can affect fat storage and weight gain. - A lack of sleep may contribute.
Do social factors affect the risk of obesity?
The authors of a 2017 review of studies from around the world suggest that the following social factors, among others, may play a role:
- stress due to trauma, relationship problems, financial difficulties, or a combination
- levels of health and dietary awareness
- workplace settings, including working hours and the likelihood of eating takeout
- access to and availability of healthy food
- access to green space and other considerations involving urban living and activity levels
According to the Centers for Disease Control and Prevention (CDC), obesity affects around
However, a
A person with obesity may experience:
- sweating
- tiredness
- joint and back pain
- difficulty breathing
- sleep problems, including snoring
- difficulty with physical activity
- low confidence and feelings of isolation
- high blood pressure and other symptoms of metabolic syndrome
- symptoms of other complications, which we describe below
Indications of severe obesity include:
- a high buildup of fat around the body
- a BMI of
40 or above - signs of complications, such as hypertension
The complications of obesity
- metabolic syndrome, which includes type 2 diabetes, high blood pressure, and other features
- high levels of “bad” cholesterol and low levels of “good” cholesterol
- high levels of triglycerides
- stroke
- heart disease
- gallbladder disease
- osteoarthritis
- sleep apnea and other breathing problems
- mental health conditions, such as depression and anxiety
- some cancers
- body pain
- difficulty with daily functions and activities
- a
higher risk of hospitalization due to COVID-19, especially among Hispanic and Black Americans
These conditions can affect a person’s life expectancy and quality of life.
If a person visits their doctor with concerns about their weight or BMI, the doctor will likely:
- measure their weight and height to confirm their BMI
- ask about dietary and exercise habits
- consider the person’s individual and family medical histories
- do blood tests to look for health conditions that may underlie obesity
- test for complications that may need medical attention, such as high blood pressure
If a person has severe obesity or complications relating to it, a doctor may:
- recommend an appropriate weight loss plan
- work with the person to develop an exercise plan
- recommend a physical therapy plan if the person has limited mobility
- prescribe medication, such as orlistat (Alli), which reduces the amount of fat that the body absorbs
- recommend bariatric surgery, if other options do not help
- address any complications, such as type 2 diabetes and other features of metabolic syndrome
A person should work with their doctor or a nutritionist to develop a suitable plan and follow the instructions carefully. Losing weight too rapidly or starting vigorous exercise too quickly can have negative effects.
Also, various weight loss drugs are available online, but they may not be safe or effective.
If other options do not help, the doctor may recommend surgery. Some of these procedures include:
- gastric banding, in which a surgeon places a ring around the stomach, limiting the amount of food that can enter
- gastric bypass, which aims to increase the feeling of fullness and lead to the absorption of fewer calories
- sleeve gastrectomy, in which the surgeon removes part of the stomach
- intragastric balloon, a temporary measure in which the surgeon places a balloon in the stomach to take up space
If a person loses a significant amount of weight, they may have unwanted folds of skin. Surgery can also address this.
There is no single way to lose weight or prevent weight gain. The best option will depend on the individual. However, dietary strategies and exercise can help.
Dietary tips can include:
- consuming plenty of fresh fruits and vegetables
- favoring whole or unprocessed foods
- avoiding trans fats and saturated fats and opting for healthy fats, such as from safflower or corn oils
- limiting the intake of sugar and sweetened foods
- monitoring the caloric intake, if a healthcare professional recommends this
- using a
smaller plate - eating only at regular times
- eating
more slowly - avoiding triggers and habits that lead to overeating, such as having some cake with coffee at break times
Current guidelines recommend that, when possible, adults get at least
A doctor can advise about how much and what type of exercise a person should do, depending on their overall health, age, and other factors.
Severe obesity is not an illness, but it can increase the risk of a wide range of health conditions, some of which can be life threatening. In most cases, severe obesity is reversible.
Anyone who has concerns about obesity or its possible symptoms should receive medical advice. Treatments can enable a person to adjust their weight and may help prevent potentially serious complications.