Obesity

Understanding Obesity

What is obesity?

The medical definition of obesity is based on the amount of body fat a person has. A person can weigh more than what is thought to be healthy without being obese. For example:

A person may weigh too much because his or her body retains too much water, called edema. Though this is not a healthy situation, the person is not obese.

Some athletes, such as football players and body builders, may weigh more than what is normally considered a healthy weight, but their excess weight is muscle, not fat.

Until recently, a person was thought to be obese if he or she weighed at least 20% more than his or her ideal body weight. However, ideal body weight tables have been replaced by the body mass index (BMI). The BMI is also based on your height and weight, and it gives a better -- but not perfect -- estimate of body fat.

Attitudes about the causes of obesity are changing as we learn more about the condition. People who are obese were once thought to lack self-control and have poor eating habits. Though it is true that many Americans eat too much and exercise too little, recent research has shown that genetic factors also play a role in obesity.

Because of this research, obesity is now thought to be a chronic disease. This means dieting once in a while is not enough to take care of the problem. Obesity must be treated for the rest of the person's life if it is to be controlled.

What are the risks?

People who are obese are much more likely to have certain health problems, such diabetes, high blood pressure, heart disease, and stroke. This is even more likely if the person also has high cholesterol or triglyceride (fat) levels in the blood, as obese people often do.

A person who is very obese may have breathing problems including sleep apnea. Women who are obese have a greater risk of uterine, breast, and gallbladder cancer. Men and women who are obese have an increased risk for colorectal cancer and gallstones. Men who are obese have an increased risk for prostate cancer.

Extra weight puts more stress on the joints than normal, especially in the legs and lower back. Because of this, people who are obese are more likely to develop arthritis, especially in the back, knees, and hips.

How do I know if I'm obese?

Your family doctor can usually tell you whether your weight is a health problem and can offer suggestions for treatment. However, some doctors are better prepared to treat obesity than others.

Your doctor may refer you to other health professionals: an endocrinologist, to determine if your obesity is due to a hormone problem like an underactive thyroid gland; a registered dietitian, to help you determine how many calories you need and how best to get them; or an exercise specialist, to help you develop a safe and effective exercise program.

If it appears that part of the reason for your obesity is an emotional problem -- possibly caused by depression, anxiety, sexual or physical abuse, family problems, or drug or alcohol use -- your doctor may suggest you see a counselor or psychiatrist.

How is obesity treated?

Three factors are considered when treating obesity: the severity of the obesity, the presence of other risk factors for heart disease, and the possibility of other health problems that may be caused or made worse by excess weight.

Doctors now realize that it may be unrealistic to attempt to get a person who is obese to lose a large amount of weight and keep it off. However, recent studies have shown that even modest weight loss provides significant health benefits by reducing the risk for diabetes, heart disease, stroke, high blood pressure, and other diseases.

The American Association of Clinical Endocrinologists (AACE) suggests the following guidelines for designing a weight-loss program.

Everyone who is trying to lose weight should change his or her eating and exercise habits. Counseling or support groups are an important part of successfully making these lifestyle changes.

Doctors recommend that depression or a physical problem that limits a person's ability to exercise be treated, if possible, before starting a weight-loss program. People with untreated depression often have a difficult time staying on a weight-loss program. If a person is unable to do at least mild exercise, he or she will have difficulty losing weight.

Weight-loss medications, either prescription or nonprescription, should only be used along with a weight-loss diet and exercise. Use of medications without lifestyle changes is unlikely to have great, long-term success.

A very low-calorie diet may be considered if you need to lose weight quickly to protect your health and your doctor decides it is a safe method for you to use. People are not kept on this diet for long periods of time because the diet lacks certain nutrients the body needs.

Even if you and your doctor have developed a plan for weight loss, the daily decisions needed to make the plan work are up to you. Healthy, long-term success in conquering obesity depends on changing your eating and exercise habits.

Surgery is a rarely used treatment for obesity. Many doctors will consider it only for people who have not been able to lose weight with other treatments and who are at high risk for developing other health problems because of their weight.

Reviewed by Charlotte E. Grayson, MD, September 2003.