What Are The Causes Of Obesity?

Avatar for Hadyn Luke Hadyn Luke posted this on Tuesday 8th of October 2019 Hadyn Luke 08/10/2019


What Are The Causes Of Obesity?

The dangers of obesity are widely known, from developing Type 2 diabetes to coronary heart disease. In 1991, the government formally recognised that obesity was a sufficient threat to the nation’s health to require a targeted response.

But is obesity all about lack of willpower, or are other factors at play?

New report says obesity is not a choice

In September 2019, the British Psychological Society (BPS) published a report: “Psychological perspectives on obesity: Addressing policy, practice and research priorities.”

This looked into the various and complex causes of obesity, along with weight discrimination, changing behaviours, prevention and weight management.

The conclusion was that obesity was not a choice, but could be caused by a variety of different factors, which might be biological, psychological and/or social. The best approach to combatting obesity, it recommended, was a “biopsychosocial” one, rather than “fat shaming” – shaming, blaming and stigmatising those who are obese.

How is obesity measured and what are the dangers of obesity?

Obesity is considered a chronic disorder and classed as a disease. An individual is usually considered obese if they have a Body Mass Index (BMI) of 30 or higher.

The NHS website states that it is estimated that one in every four adults is obese, and around 1 in every 5 children between 10 and 11.

The dangers of obesity include developing any of the following:

  • Type 2 diabetes
  • Coronary heart disease
  • Stroke
  • Certain cancers (breast, bowel, womb)
  • Osteoarthritis
  • Asthma
  • Sleep apnoea
  • Liver or kidney disease
  • Mental health issues

Obesity can also affect quality of life, for example by limiting movement and causing shortness of breath, back pain or joint pain.

What are the causes of obesity?

While willpower can be a factor, there are many other more pressing reasons for a person to become obese.

These include:

Genetics – this is considered a key factor in the report: “Over 100 twin and family studies have established that 50-90 per cent of weight differences between people can be explained by genetic influences.” There are 100+ genes that can affect weight difference, from controlling appetite regulation to emotional eating.

Stress – stress of any kind has been shown to be linked to obesity, directly and indirectly. The report states that: “Chronic activation of the stress response system results in greater accumulation of internal body fat… Stress also influences a range of behaviours, such as sensitivity to food cues and cravings that lead to eating more or choosing more calorific-dense foods”.

Mental health – not only can mental health issues lead to obesity but some of the drugs used to treat conditions such as depression can increase appetite. It can also be a two-way street: poor mental health can cause weight gain and vice versa.

While eating disorders such as anorexia and bulimia are widely known about, Binge Eating Disorder (BED) tends to be under-recognised. This is a serious but treatable disorder where someone has repeated episodes of bingeing, including eating when they are not hungry or continuing to eat when they are uncomfortably full. The bingeing is usually followed by feelings of guilt and shame.

Ethnicity – government figures from 2017-2018 state that “Black adults were the most likely out of all ethnic groups to be overweight or obese.” This was followed by white British adults, with those from the Chinese ethnic group least likely to be overweight or obese. The number of those who were overweight or obese in the following groups: Asian, Other white, Mixed and Other ethnic, was also lower than the national average. See: https://www.ethnicity-facts-figures.service.gov.uk/health/preventing-illness/overweight-adults/latest.

Age – we’ve all heard the term middle-age spread and there’s no doubt that factors relating to age can affect obesity. This might be age-related changes to how easily we put on weight or changes to the type and amount of exercise we do.

Hormones – the hormones that regulate appetite can be affected by stress, overeating or binge eating. This can result in increased consumption of food, as the balance of hormones affects our ability to recognise when we are full and encourages the consumption of foods high in fat and sugar.

Lifestyle – a sedentary lifestyle can contribute to obesity through lack of exercise or spending long hours seated at work. Our eating habits can also be rooted in our lifestyle, for example eating a fry up every morning, overeating at business lunches and dinners or consuming excess alcohol while socialising.

Physical activity – keeping active can help combat obesity, from taking a walk every day to following a cardio fitness class to weight training with a personal trainer. Physical activity often goes hand-in-hand with lifestyle and diet, in that those who are interested in keeping fit often exercise regularly and follow a healthier diet.

Diet – while other factors such as genetics are important, the quality of our diet can be as important as the quantity we eat. Additionally, the approach to losing weight often promoted by the diet industry – short-term highly restricted eating – is mentioned in the report as a factor that can cause physical and psychological harm.

Socio-economic – our food preferences and habits are shaped in childhood and carried through to adulthood. These are often influenced by socio-economic factors, such as food poverty, which can lead to the consumption of more food that is high in energy and low in nutrition.


Obesity is a serious, life-limiting condition and the number of people classified as obese is rising. However, the solution does not lie fat shaming or blaming all weight gain on an individual’s lack of willpower.

Instead, the BPS report recommends a “biopsychosocial” model, which takes into account the range of factors behind weight gain and offers a framework that focuses on what causes certain types of behaviour rather than the behaviour itself.

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