Obesity

DEFINITION

Obesity is a complex disorder involving an excessive amount of body fat. Obesity isn’t just a cosmetic concern. It increases your risk of diseases and health problems, such as heart disease, diabetes and high blood pressure.

Being extremely obese means you are especially likely to have health problems related to your weight.

The good news is that even modest weight loss can improve or prevent the health problems associated with obesity. Dietary changes, increased physical activity and behavior changes can help you lose weight. Prescription medications and weight-loss surgery are additional options for treating obesity.

CAUSES

Although there are genetic, behavioral and hormonal influences on body weight, obesity occurs when you take in more calories than you burn through exercise and normal daily activities. Your body stores these excess calories as fat.

Obesity can sometimes be traced to a medical cause, such as Prader-Willi syndrome, Cushing’s syndrome, and other diseases and conditions. However, these disorders are rare and, in general, the principal causes of obesity are:

  • Inactivity. If you’re not very active, you don’t burn as many calories. With a sedentary lifestyle, you can easily take in more calories every day than you use through exercise and normal daily activities.
  • Unhealthy diet and eating habits. Weight gain is inevitable if you regularly eat more calories than you burn. And most Americans’ diets are too high in calories and are full of fast food and high-calorie beverages.

SYMPTOMS

Obesity is diagnosed when your body mass index (BMI) is 30 or higher. Your body mass index is calculated by dividing your weight in kilograms (kg) by your height in meters (m) squared.

BMI

  • Below 18.5
  • 18.5-24.9
  • 25.0-29.9
  • 30.0-34.9
  • 35.0-39.9
  • 40.0 and higher


For most people, BMI provides a reasonable estimate of body fat. However, BMI doesn’t directly measure body fat, so some people, such as muscular athletes, may have a BMI in the obese category even though they don’t have excess body fat. Ask your doctor if your BMI is a problem.

When to see a doctor

If you think you may be obese, and especially if you’re concerned about weight-related health problems, see your doctor or health care provider. You and your provider can evaluate your health risks and discuss your weight-loss options.