Obesity as a disease

In 1997, following consultation with the International Obesity TaskForce (IOTF, now part of World Obesity), the World Health Organization (WHO), published Obesity: Preventing and Managing the Global Epidemic1

This ground-breaking document clearly stated that obesity was a disease, specifically a ‘complex’, ‘incompletely understood’, ‘serious’ and ‘chronic’ disease which was part of a cluster of non-communicable diseases that required prevention and management strategies at both individual and societal level.

In May 2017 World Obesity published its position statement recognising obesity as a disease. Taking the form of a review article by a group of expert advisers, published in Obesity Reviews, the position adopted by World Obesity is now fully in accordance with the position taken by the American Medical Association in 2013 and by many of the World Obesity Federation’s member associations.

The World Obesity statement concurs with the view expressed by Kopelman and Finer2 that defining obesity as a disease can serve several valuable purposes:

  • To promote an understanding that obesity is not simply an inevitable consequence of an affluent and increasingly sedentary society but is a ‘malignant’ condition of modern life that can be avoided or reversed with substantial health benefit to an individual and society as a whole.
  • To highlight to the sufferers, the medical profession and the public at large that obesity (or excessive fatness) is a potentially life-threatening disorder.
  • To receive appropriate recognition from healthcare planners, health service funders, health authorities and local and national governments that obesity is epidemic within society, affects all ages, and requires attention at the highest policy levels.

In supporting the position, World Obesity recognises that arguments against the classification of obesity as a disease have been made on the grounds that obesity is risk factor for other conditions rather than a disease in its own right (for example in the Global Burden of Disease studies3) and that declaring obesity a disease would define a significant proportion of the population in many countries as being ill, and potentially emphasise medical approaches to treatment at the expense of behavioural and societal interventions.

In a Comment published alongside the World Obesity statement, World Obesity argues that defining obesity as a disease does not lessen but rather increases society’s responsibility to prevent excess weight gain through a range of population-wide interventions to promote optimum health. Such population-wide measures are not only preventive but are also integral to the treatment process, reducing the risk of weight re-gain for people who have successfully lost weight.

Lastly, World Obesity is concerned that any moves to redefine obesity should be sensitive to the stigma experienced by people with weight concerns. For some, a medical diagnosis can help to reduce a person’s internalised stigma or belief that their excess weight is entirely self-inflicted and shameful. It may change the public discourse about blame for the condition (how often is blame for heart disease or cancer put on the individual?) and alter perceptions in the healthcare services, encouraging greater empathy with patients. On these grounds alone, the definition of obesity as a disease is surely justified.

  1. World Health Organization, 1999. Obesity: Preventing and Managing the Global Epidemic. WHO Technical Report Series 894, Geneva: World Health Organization.
  2. Kopelman PG, Finer N. Reply: Is obesity a disease? Int J Obes Relat Metab Disord. 2001, 25:1405-6.
  3. Global Burden of Disease studies 2010 and 2013. Lancet online, 2015. (http://www.thelancet.com/global-burden-of-disease)