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The science of obesity

As defined by the International Classification of Diseases, obesity is a chronic disease that affects over 764 million adults worldwide.1-4 It has a substantial health impact with 200+ possible complications affecting many organs and systems.5,6 As a result, healthcare professionals see patients with obesity throughout their clinical practice and widely recognise it as a serious, chronic disease that often relapses.7 With the number of people living with obesity on the rise,4 evidence-based tools are needed to help tackle the growing obesity epidemic.



Rethink Obesity® aims to provide scientific and evidence-based information in an easily accessible manner to healthcare professionals, and aims to help enhance the care of patients living with overweight and obesity.

Watch the video above to learn more about the science of obesity.

More on overweight & obesity

Access the latest information about the complications of obesity and the role of weight management.

A chronic progressive disease

A chronic progressive disease

Learn about obesity, its international classification as a chronic disease and what factors can influence obesity.

Benefits of weight loss

Benefits of weight loss

Learn about the value of 10–15% weight loss, weight maintenance and its impact on health.

Complications of obesity

Complications of obesity

Is obesity more than just excess weight? Read about the complications associated with obesity which can affect an individual’s health.

Handy tools and resources

Access downloadable resources for obesity. These are designed for you and your patients to optimise weight management.


5 steps on obesity

Obesity stigma can make talking about weight management a sensitive issue. The ‘5 steps on obesity’ guidance document provides support for you to start and continue the conversation to find the right management option for your particular patient.

Goal setting for weight management

Once a weight journey has been explored and your patient’s personal challenges identified, you can progress to setting achievable goals together. This leaflet sets out potential approaches to healthy eating and increased physical activity.

Download our goal setting weight loss management template for your patients.

  1. Bray GA, Kim KK, Wilding JPH, et al. Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Obes Rev. 2017;18: 715–723.
  2. World Obesity Federation (2021) Obesity is a disease. Available at: www.worldobesityday.org/assets/ downloads/Obesity_Is_a_Disease.pdf. Accessed November 2023.
  3. International Statistical Classification of Diseases and Related Health Problems (11th ed,; ICD-11; World Health Organization, 2019).
  4. World Obesity. World Obesity Atlas 2022. Available at: https://www.worldobesity.org/resources/resource-library/world-obesity-atlas-2022. Accessed November 2023.
  5. Who.int. 2021. Obesity and overweight. [online] Available at: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight. Accessed November 2023.
  6. Yuen M, Earle R, Kadambi N, et al. A systematic review and evaluation of current evidence reveals 195 Obesity-Associated Disorders (OBAD). The obesity society 2016 abstract book 2016:92.
  7. Caterson ID, Alfadda AA, Auerbach P, et al. Gaps to bridge: Misalignment between perception, reality and actions in obesity. Diabetes Obes Metab. 2019; 21:1914-1924.