Weight and body size are two of the most visible aspects of a human being, making both particularly vulnerable to assumptions and judgement. For a long time, people have associated larger bodies and excess body weight with eating too much food and not getting enough exercise. As a result, people who live with obesity often experience stigma in some or all areas of their everyday lives.
We now know that it is just not as simple as that. While diet and physical activity play critical roles in maintaining a healthy weight and body size, it is now scientifically recognised that other factors, including genetics, hormones, medications, mental health, stress, sleep, socioeconomic circumstances can all affect weight management too.
As a result of this new information, the obesity disease debate has come under scrutiny again. Today, major health organisations such as the World Health Organization (WHO) now recognise obesity and overweight as a chronic and often complex disease (1).
Why is obesity considered a disease?
According to data from the World Obesity Federation, it is estimated that nearly 3 billion people globally are living with overweight or obesity (2).
The WHO has long recognised obesity as a significant public health issue. However, in recent years its guidance has explicitly moved towards describing it as a chronic, relapsing disease that arises from complex interactions between genetics, biology, behaviour and the environment (1). This view is based on evidence showing that obesity involves changes in body systems that regulate appetite, metabolism, energy levels and fat storage. The change also reflects decades of research in this area, for example a 2021 study, referencing a prior 2007 study, showed that variations in genes can alter eating behaviours (3) and a 2014 study that demonstrates that environmental factors such as availability of high-calorie foods has contributed to the rise in obesity rates (4).
The NHS has adopted a similar stance, recognising obesity and overweight as a contributor to not only an increased risk of certain health conditions such as type 2 diabetes and cardiovascular disease, but also socioeconomic barriers, like getting and staying in employment and career progression pathways (5).
Why some people push back on the "disease" label
Not everyone agrees that obesity and overweight should be labelled as a disease, instead arguing that while biology plays a role, diet, physical activity and other health-based behaviours remain the greatest influences on weight and body size.
Their concern is that by referring to obesity in this way, it could unintentionally reduce the personal responsibility people feel to take control of these factors and improve their overall health and wellbeing. They believe that public health focus should remain firmly on improving the controllable factors of nutrition, physical activity and healthy habits to try and reduce the number of people living with obesity both now and in the future.
Why the obesity as a disease label matters in practice
The purpose of labels is to help people to get a better understanding of what something is beyond what they can physically see. A disease label attached to obesity is no different.
Recognising obesity as a disease may influence how obesity is understood, and how individuals, society as a whole and healthcare systems respond to it. It may:
Change the conversation from blame to healthcare, reducing stigma and encouraging a more holistic approach to treatment.
Encourage healthcare professionals to look beyond weight and look at other factors that could be contributing to weight gain such as taking certain medications or mental health concerns.
Encourage and improve access to proven treatments, including behavioural support, weight loss medications, and if appropriate, surgical interventions.
Needing support with weight management is not a sign of failure or a lack of willpower. Obesity is a complex condition, with the first step towards better health being through reliable, reputable medical advice.
A licensed healthcare provider will be able to assess your current health and weight loss goals and recommend the right type of support. This may mean signposting you to support with nutrition and exercise, or they may suggest exploring the many weight loss medications currently available, such as weight loss tablets or GLP1 injections which are often recommended alongside making positive lifestyle changes.
FAQs
Does calling obesity a disease mean that lifestyle choices do not matter?
Absolutely not. Eating a healthy, balanced diet, getting regular exercise, decent sleep and other lifestyle factors are still important for weight maintenance. The label means that weight is affected by many things, including lifestyle choices.
Does this mean that people who are obese have no control over their weight?
No, but it does mean that some people may have less control over their weight than others because of factors such as genes, hormones and health conditions.
Does admitting obesity and overweight is a disease mean that everyone who fits into this category needs medical treatment?
While maintaining a healthy weight is important, admitting that obesity is a disease doesn’t mean that everyone who is classed as overweight or obese should start using weight loss treatment. Everyone is different and treatment and support should be personalised as some people may require lifestyle support alone to lose weight, while others will explore additions such as weight loss medications
Where can I get help if I am concerned about my weight?
If you’d like to start taking steps towards treating obesity, our experienced, licensed prescribing team would be happy to help. Please get in touch.
References
World Health Organization. Obesity and Overweight [Internet]. World Health Organization. 2025 May [cited 2026 Jul 30]. Available from: https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
World Obesity Federation. Prevalence of obesity [Internet]. World Obesity Federation. 2024 [cited 2026 Jul 30]. Available from: https://www.worldobesity.org/about/about-obesity/prevalence-of-obesity
Loos RJF, Yeo GSH. The genetics of obesity: from discovery to biology. Nature Reviews Genetics. 2021 Sept 23;23(23):1–14. https://www.nature.com/articles/s41576-021-00414-z
Ng M, Fleming T, Robinson M, Thomson B, Graetz N, Margono C, et al. Global, regional, and National Prevalence of Overweight and Obesity in Children and Adults during 1980-2013: a Systematic Analysis for the Global Burden of Disease Study 2013. Lancet (London, England) [Internet]. 2014 [cited 2026 Jul 30];384(9945):766–81. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)60460-8/abstract
NHS England. NHS England » Obesity [Internet]. England.nhs.uk. 2019 [cited 2026 Jul 30]. Available from: https://www.england.nhs.uk/ourwork/prevention/obesity/