Obesity means having too much body fat. It is not the same as overweight, which means weighing too much. A person may be overweight from extra muscle, bone, or water, as well as too much fat. But both terms mean that someone's weight is higher than what is thought to be healthy for their height.
More than 1 out of every 3 adults in the United States is overweight.
Experts often rely on a formula called the body mass index (BMI) to determine if a person is overweight. The BMI estimates your level of body fat based on your height and weight.
- A BMI from 18.5 to 24.9 is considered normal.
- Adults with a BMI of 25 to 29.9 are considered overweight. Since the BMI is an estimate, it is not accurate for all people. Some people in this group, such as athletes, may have a lot of muscle weight, and therefore not as much fat. These people will not have an increased risk of health problems due to their weight.
- Adults with a BMI of 30 to 39.9 are considered obese.
- Adults with a BMI greater than or equal to 40 are considered extremely obese.
- Anyone more than 100 pounds (45 kilograms) overweight is considered morbidly obese.
The risk of many medical problems is higher for adults who have excess body fat and fall into the overweight groups.
CHANGING YOUR LIFESTYLE
An active lifestyle and plenty of exercise, along with healthy eating, is the safest way to lose weight. Even modest weight loss can improve your health. Get support from family and friends.
Your main goal should be to learn new, healthy ways of eating and make them part of your daily routine.
Many people find it hard to change their eating habits and behaviors. You may have practiced some habits for so long that you may not even know they are unhealthy, or you do them without thinking. You need to be motivated to make lifestyle changes. Make the behavior change part of your life over the long term. Know that it takes time to make and keep a change in your lifestyle.
Work with your health care provider and dietitian to set realistic and safe daily calorie counts that help you lose weight. Keep in mind that if you drop your weight slowly and steadily, you are more likely to keep it off. Your dietitian can teach you about:
Overweight - body mass index; Obesity - body mass index; BMI
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Cowley MA, Brown WA, Considine RV. Obesity: the problem and its management. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 26.
Jensen MD, Ryan DH, Apovian CM, et al. 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 Society. Circulation. 2014;129(25 Suppl 2):S102-S138. PMID: 24222017 www.ncbi.nlm.nih.gov/pubmed/24222017.
Review Date 1/21/2018
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.