Overweight and obesity are increasingly common conditions in the United States. They are caused by the increase in the size and the amount of fat cells in the body. Doctors measure body mass index (BMI) and waist circumference to screen and diagnose overweight and obesity. Obesity is a serious medical condition that can cause complications such as metabolic syndrome, high blood pressure, atherosclerosis, heart disease, diabetes, high blood cholesterol, cancers and sleep disorders. Treatment depends on the cause and severity of your condition and whether you have complications. Treatments include lifestyle changes, such as heart-healthy eating and increased physical activity, and Food and Drug Administration (FDA)-approved weight-loss medicines. For some people, surgery may be a treatment option.