People who are obese are at risk for several health conditions. These include:

  • type 2 diabetes
  • stroke
  • high blood pressure
  • heart failure
  • heart disease
  • osteoarthritis
  • gallbladder disease
  • chronic back pain
  • certain types of cancer (e.g., colorectal, breast, ovarian, pancreatic)
  • obstructive sleep apnea
  • reflux
  • skin infections

To take heart disease as an example, the risk of heart disease increases with increasing weight. For those who are a normal weight, their risk of heart disease is about 8%, whereas people who are overweight, obese, or severely obese have a risk of about 15%, 26%, and 45%, respectively.

Obesity can also affect emotional health and lead to low self-esteem and possibly depression.

Another health risk associated with being overweight or obese is metabolic syndrome. Metabolic syndrome as a multifaceted condition characterized by a distinctive constellation of abnormalities that include abdominal obesity, high blood pressure, high cholesterol, and insulin resistance. Metabolic syndrome is now considered to be an important early sign of coronary artery disease and type 2 diabetes. The concern with increased insulin resistance is that it causes poor blood sugar control, high blood pressure, and abnormal cholesterol and triglyceride levels. These are all risk factors that make up the metabolic syndrome.

The North American criterion for a diagnosis of metabolic syndrome is having 3 or more of the following:

  • abdominal obesity with a waist circumference over 102 cm (40 inches) for men or over 88 cm (35 inches) for women
  • fasting blood sugar equal to or over 5.6 mmol/L (100 mg/dL)
  • blood pressure equal to or over 130/85 mm Hg
  • HDL-C (high-density lipoprotein) less than 1.0 mmol/L (38.7 mg/dL) for men and less than 1.3 mmol/L (50 mg/dL) for women
  • triglycerides equal to or over 1.7 mmol/L (150 mg/dL)

Although other definitions of metabolic syndrome are used in other countries, in all cases, abdominal obesity is an important part of the definition.

Losing weight can significantly reduce these health risks. For more information on losing weight safely, see "Managing obesity: an overview."