Being overweight is associated with a higher risk of disease, particularly if body fat is concentrated around the abdomen. The estimates of attributable mortality and burden due to being overweight and obese have been made using a measure of high body mass index (BMI) calculated as weight (kg) divided by height squared (m²). BMI was chosen as a simple measurement of body weight in relation to height because it is in principle easier to measure at the population level than body fat. Analysis of the relationship between BMI and mortality and morbidity suggests that the theoretical optimum mean population BMI is around 21 kg/ m². The disease outcomes for overweight and obesity include:

• Diabetes type 2
• Ischaemic heart disease
• Stroke
• Hypertensive disease
• Osteoarthritis
• Cancers (colon, kidney, endometrial, and postmenopausal breast cancer)
  

There are approximately 350 million obese people (BMI ≥30.0) and over 1 billion overweight people (BMI ≥25) in the world. Over all about 2.5 millions deaths are attributed to overweight/obesity worldwide.