An Overview of Obesity

In This Article
Table of Contents

Obesity is a disease characterized by abnormal or excessive fat accumulation that may impair health. It is a global health epidemic with more than 650 million people affected worldwide, according to the World Health Organization 2016 statistics. Obesity is a contributing factor to many diseases, including diabetes, cardiovascular disease, musculoskeletal disorders, and certain cancers.

The medical definition of obesity is based on the calculation of body mass index (BMI), a formula of weight in kilograms divided by height in meters squared. A normal BMI is between 18.5 and 24.9. Overweight is defined as a BMI of 25.0 to 29.9, and a BMI of 30.0 or greater is obese. The diagnosis of morbid obesity is applied at a BMI of 40.0 or greater.


The primary symptom of obesity is an excessive or abnormal amount of body fat. 

Carrying around extra weight can also lead to other symptoms, including feeling out of breath, increased sweating, snoring, fatigue, back and joint pain, low confidence and self-esteem, and feelings of isolation. 

In addition, obesity can lead to other health problems including hypertension, high cholesterol, type 2 diabetes, and stroke. 


Obesity is caused by an energy imbalance between calories consumed and calories expended, although some people are more predisposed to obesity than others. 

Environmental factors that contribute to obesity include leading a sedentary lifestyle, consuming added sugars, dining out too frequently, and not getting enough sleep, among others. 

Some medications and medical conditions can also lead to weight gain. There is also a genetic component to obesity.

As with many chronic diseases, such as diabetes and cardiovascular disease (both of which are also linked to obesity), obesity is largely—if not almost entirely—preventable.

Strategies for preventing obesity include being aware of your risk factors, being vigilant about adhering to a healthy diet, making time for daily exercise, and staying in motion throughout the day.


A diagnosis of obesity is based on BMI calculations. You can calculate your BMI using online tools, like this calculator from the National Institute of Heath.

If your BMI is 25 or over (the threshold for overweight), talk to your doctor about the next steps for treating your obesity. Usually, changes to your diet and physical activity level will be recommended first.


The goal of treatment for obesity is to lose weight to reduce risk factors. Research shows losing just 5% to 10% of your body weight if you are overweight or obese can make a tremendous difference in your health.

These include improvements in risk factors for cardiovascular diseases, such as high cholesterol and high blood pressure, as well as a greatly reduced risk of developing type 2 diabetes.

A variety of treatments are now available for obesity and range from diet and lifestyle changes to anti-obesity medications, medical devices, and surgical procedures that induce weight loss, like bariatric surgery.

Medications to treat obesity include stimulants that reduce appetite and increase energy, antidepressants and other drugs that work on brain chemistry to reduce food cravings, dietary fat blockers that reduce the absorption of fat and combination medicines.

Bariatric surgery is an option for those with obesity who have already tried diet and lifestyle changes and anti-obesity medications, and still have a BMI of 40 or greater, or a BMI of 35 or greater with at least one other medical condition known to be caused by obesity, according to the 2013 obesity guidelines released by the AHA, the American College of Cardiology (ACC), and The Obesity Society (TOS).

In the United States, the most popular form of bariatric surgery (also known as “weight-loss surgery”) is the gastric sleeve procedure (also known as sleeve gastrectomy).

If you’ve been diagnosed with obesity, be sure to undergo any bloodwork your physician recommends, especially blood sugar, liver, and thyroid tests, which can uncover diseases related to obesity.

According to the U.S. Preventive Services Task Force (USPSTF), screening for diabetes by checking blood sugar is recommended for adults who are overweight or obese and are between the ages of 40 to 70 years. Ideally, this would be done annually as part of the routine health exam and cardiovascular risk assessment.


There are support groups and networks that can help. Overeaters Anonymous, for instance, is a community-based support group modeled on a 12-step program. Meetings are held worldwide, and members can remain anonymous.

Additionally, if you think you may be an addictive eater, there is Food Addicts Anonymous, another support group that can help, especially if you find yourself engaging in eating-disordered behaviors or turning to food for emotional reasons.

The important thing to remember is that obesity is treatable. While it will take dedication and commitment on your part, as well as serious and well-thought-out changes to your usual lifestyle, you should never give up—the benefits to your long-term health are far too significant.

A Word From Verywell

Living with obesity can be difficult. But remember—fortunately, obesity is treatable and can be reversed. Any small changes you can make will be worth it. This can be done through diet and lifestyle changes, medications, surgical procedures, or a combination of treatments.

Was this page helpful?

Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. World Health Organization. 10 facts on obesity. 2017.

  2. National Institute of Diabetes and Digestive and Kidney Disorders. Health Risks of Being Overweight. 2015.

  3. National Heart, Lung, and Blood Institute. Overweight and Obesity.

  4. Wing RR, Lang W, Wadden TA, et al. Benefits of modest weight loss in improving cardiovascular risk factors in overweight and obese individuals with type 2 diabetes. Diabetes Care. 2011;34(7):1481-6. doi:10.2337/dc10-2415

  5. Jensen MD, Ryan DH, Apovian CM, et al; American College of Cardiology/American Heart Association Task Force on Practice Guidelines; Obesity Society. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity SocietyCirculation. 2014;129(25 Suppl 2):S102-38. doi:10.1161/

  6. Siu AL; U.S. Preventive Services Task Force. Screening for Abnormal Blood Glucose and Type 2 Diabetes Mellitus: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2015;163:861-8. doi:10.7326/M15-2345

Additional Reading