Class 3 Obesity: Symptoms, Causes, and Treatment

• Genetics Obesity tends to run in families, with specific genes linked to weight gain.
• Hormones Hormone imbalances can affect metabolic health. For example, low levels of thyroid hormone or high levels of the stress hormone cortisol can lead to weight gain (although these conditions account for a small proportion of obesity cases).
• Cultural Factors Cultures that promote calorie-dense foods and large portion sizes can influence a person’s obesity risk.
• Socioeconomic Status Low socioeconomic status can contribute to weight gain. Lack of access to healthy foods and recreational facilities like parks is also associated with obesity.
• Environment Exposure to certain chemicals called obesogens can alter hormones and increase body fat.
• Sex Women are more likely than men to develop obesity.
• Age Class 3 obesity tends to affect adults ages 40 to 59 the most.
• Race Non-Hispanic Black adults have the highest rates of class 3 obesity.

• BMI assessment
• Waist circumference measurement
• Skin thickness measurement
• Urine tests
• Blood tests that include complete blood cell counts, a basic metabolic panel, liver function, cholesterol levels, triglyceride levels, kidney function, blood sugar, thyroid function, C-reactive protein, and vitamin D levels
• Other tests, such as an electrocardiogram for heart health or a sleep study

Treatment options for class 3 obesity typically include medications, surgery, and therapy.

Medications

• diethylpropion (Tenuate)
• liraglutide (Saxenda)
• naltrexone/bupropion (Contrave)
• orforglipron (Foundayo)
• orlistat (Alli)
• phendimetrazine (Bontril)
• phentermine-topiramate (Qsymia)
• semaglutide (Wegovy)
• tirzepatide (Zepbound)

Surgery

Weight loss surgery, which is known as bariatric surgery, is considered the gold standard treatment for people with class 3 obesity when lifestyle changes and medications don’t work.

• Gastric Bypass A surgeon connects a small part of the stomach to the middle of the intestine, causing food to bypass the first part of the intestine and thereby promoting feelings of satiety with less food. This procedure also reduces the number of calories the body can absorb.
• Sleeve Gastrectomy A surgeon removes 75 to 80 percent of the stomach, reducing stomach capacity and altering hunger-related hormones such as ghrelin.

Some possible risks and complications of bariatric surgery include:

• Blood clots
• Difficulty absorbing nutrients
• Dumping syndrome (which occurs when food leaks from the stomach into the small intestine more quickly than it should)
• Heart events
• Infection and bleeding
• Vitamin and mineral deficiencies

Therapy

A medical professional can help you determine which therapy would be the most effective type for your situation.

While healthy lifestyle habits can help reduce the risk of weight gain, class 3 obesity is influenced by complex genetic, biological, and environmental factors, so prevention isn’t always possible. With that said, there are several strategies that may help manage class 3 obesity and some of its complications.

Change Your Diet for the Long Term

A registered dietitian-nutritionist can help you come up with a safe and appropriate plan for your situation. Talk to your doctor before making any drastic changes to your diet.

Exercise

Before beginning an exercise program, talk to your doctor about the type of physical activity that’s likely to benefit you most and how to start safely.

Get Enough Sleep

If you’re having trouble getting enough quality sleep, let your doctor know so they can explore potential treatment options with you. For instance, obstructive sleep apnea (a condition in which you stop breathing during sleep) can be assessed with a sleep study.

Manage Stress

• Atherosclerosis, or plaque buildup inside your arteries
• Breathing disorders, including asthma
• Certain cancers
• Depression
• Heart disease
• High blood pressure
• Metabolic dysfunction–associated steatohepatitis
• Metabolic syndrome (a cluster of conditions that increases your risk of heart disease, stroke, and diabetes)
• Osteoarthritis
• Sleep disorders, such as sleep apnea
• Type 2 diabetes

Obesity Action Coalition

This national nonprofit organization is dedicated to representing people affected by obesity, focusing on raising awareness and improving access to effective ways for preventing and treating the disease. It also provides education about evidence-based interventions and fights stigma and weight bias to ensure all people are treated equally regardless of their size.

Academy of Nutrition and Dietetics

This international organization of food and nutrition professionals is a trusted source of all food- and nutrition-related information and is committed to reducing the impact of obesity. Its website offers nutritious, well-balanced recipes for every meal, helpful meal planning tips, and dietary recommendations for people with chronic health conditions.

Overeaters Anonymous

This peer support–based community welcomes any individual recovering from an unhealthy relationship with food and body image. There are a number of ways to join, including participating in the 12-step program and joining meetings in person, online, or via phone.

Obesity Care Advocacy Network

This network is made up of a diverse group of organizations working to improve access to evidence-based obesity treatments, eliminate stigma and weight bias, and foster innovation for new obesity interventions. Its website hosts facts and data on obesity, advocacy opportunities, and news stories on advancements in obesity legislation and the latest scientific research around obesity care.

• Class 3 obesity is a chronic disease defined by a BMI of 40 or higher.
• The development of this condition can be influenced by a complex mix of lifestyle factors, genetics, hormones, socioeconomic status, and environmental factors.
• If left untreated, class 3 obesity can shorten a person’s life expectancy by up to 14 years and increase their risk of severe complications such as type 2 diabetes, heart disease, and depression.
• Effective management involves a comprehensive approach including lifestyle changes, weight loss medications, therapy, and potentially bariatric surgery.