What is Obesity?

The World Health Organisation defines overweight and obesity as “the abnormal or excessive accumulation of fat that presents a risk to health” i.e. may impair health and function.

Obesity is a serious disease process with symptoms that build slowly over an extended period of time. It can interfere with basic physical function such as breathing, walking and self-care in some instances. Long-term implications of this disease process include shorter life expectancy, serious health consequences in the form of weight related complications/ health conditions, lower quality of life, with fewer economic and social opportunities.

Inherent in the description of “disease process” as defined by the World Obesity Federation, is the recognition that not every individual who fulfills the current criteria for obesity will have a “disease” at any single point in time.

It is understood that such apparently “healthy individuals with obesity” will likely develop metabolic risk factors and physical dysfunction with age, whilst they are still living with obesity.

The causes of obesity are many and complex, and may include a combination of the following:

  • The genes you inherited from your parents
  • The way your genes interact with the environment and are expressed (epigenetics)
  • Your metabolism ie how well your body turns food into energy, which is then used to keep you alive
  • Your nutritional intake (eating habits)
  • Changes in the bacteria and cells which live in your gut (gut microbiome)
  • Your physical activity levels (including incidental and structured exercise)
  • Your environment including your surroundings/where you live, sleep patterns, stress levels, work shift patterns etc
  • Medical conditions and/or medications used to treat these conditions
  • Psychological factors-which may influence your environment but also may influence your relationship with food.

Obesity affects individuals, their families and/ or carers and the wider community.

Given its progressive nature, lifelong management will be required.

Glossary of terms:

  • The term “disease process” recognizes that the risk factors for associated disease may not be present in every individual who meets the criteria for obesity but that excessive adiposity ultimately leads to health consequences in the vast majority people.
  • The term “chronic” bears difference to the fact that obesity is persistent and the physiological changes and consequent ill health develop over time.
  • The term “relapsing” refers to the difficulty in achieving lasting reduction in weight despite successful episodes where weight and fat stores have been reduced.
  • Thus, chronic relapsing disease process can be seen as an accurate and representative description of the development and progression of obesity.
  • Inherent in the description of a disease of a “disease process” is the recognition that not every individual who fulfils the current criteria for obesity will have a “disease” at any single point in time. It is understood however that such “healthy” individuals with obesity will likely develop metabolic risk factors and physical dysfunction with age whilst they continue to live with obesity.

Adapted from the following reference:

Bray G, Kim KK, Wildling J. Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obesity Reviews 2017; 18 715 – 723.

  • The University of New South Wales
  • Obesity Australia
  • ANZMOSS – Australian & New Zealand Metabolic and Obesity Surgery Society
  • Australian and New Zealand Obesity Society
  • Royal Australian College of General Practitioners
  • Care Specialist
  • Strategic  Centre for Obesity Professional Education
  • World Obesity