World Obesity Day: “Everybody needs to act”


Obesity is one of the biggest public health challenges facing the world. Globally, the incidence of obesity has tripled since 1975,[1] and it now affects around 800 million people, with many more at risk. [2] Today is World Obesity Day, a day to raise awareness of the complex causes of obesity, increase knowledge of the condition, and tackle the stigma associated with being obese. The theme of this year’s campaign is ‘Everybody Needs to Act’, which encourages a collaborative effort to prevent and manage obesity. [3,4]

What is obesity?

The term ‘obesity’ refers to an excess of body fat, which occurs when more calories are consumed than are needed. [5] The most common measure of obesity is the Body Mass Index (BMI), which is calculated by an individual’s weight in kilograms divided by their height in metres squared. BMI scores are then graded into four categories with a BMI>30 being classed as obese. [6]

How common is obesity?

In 2018, 26% of men and 29% of women in the UK were identified as being obese.[2] In addition, 20% of children in Year 6 (age 10–11) were classified as obese, with the risk for children living in the most deprived areas being more than double those in the least deprived areas. [2]

What causes obesity?

diagram showing factors causing obesity

Contrary to the belief that weight control is all about willpower, the root causes of obesity are complex and go far beyond the ‘eat less, move more’ narrative of the past. Life in the developed world has a huge impact on people and the choices they make. [7,8]

Food is now cheaper, and portions are larger and more calorific than ever before. The food and drink industry (a huge business), spends millions of pounds each year on increasingly sophisticated marketing strategies to influence us to choose unhealthy options. These foods, which are often sugar-sweetened, stimulate reward centres in the brain making them addictive in the same way as alcohol and nicotine. People with an addictive personality type are therefore at more risk of developing obesity than the general population.  In addition, life in the modern world has become far more sedentary than that of the past, with many people now working at a desk all day, travelling in cars, and spending leisure time inactive in front of a screen.

Medical conditions, such as hypothyroidism, polycystic ovarian syndrome and depression, can all contribute to weight gain as well as certain medications used in the treatment of diabetes and mental health conditions, including antipsychotics and antidepressants. Poor sleep and stress are contributing factors for weight gain as they upset the regulation of hunger-suppressing hormones, and promote the fight or flight response, respectively.

Other risk factors include: [7,8]

  • Older age, when metabolism slows and people tend to adopt a more sedentary lifestyle
  • A family history of obesity
  • Social deprivation, which leads to poor access to healthy foods and lifestyle options
  • Misinformation online, where scientific studies can be simplified or misinterpreted.

What are the risk factors associated with obesity?

Obesity was a contributing factor in 876,000 hospital admissions in England in 2018/19, an increase of 23% from the previous year. [2] It is a risk factor for multiple medical conditions including: [10,11]

Diagram of human anatomy

In addition to an increased risk of hospitalisation and a reduction in average life expectancy of 3 years when compared with the general population, obese individuals also face multiple social barriers. They may experience weight stigma and discrimination, which may have an impact on their employment opportunities, mental health, and access to support and healthcare. [11]

Tackling obesity

Obesity is largely preventable. At a global level, a shift in modern eating habits and food culture is necessary, to enable people to easily adopt a healthy lifestyle. [1]

The following options are available in the UK to help people with obesity to lose weight and change their lifestyle: [11]

General Practitioners

Doctors can advise patients about safe methods of losing weight, namely through eating a healthy, balanced diet and taking regular exercise. They can also signpost to services such as local weight-loss groups and prescribe exercise programmes.

Psychological support

Techniques such as cognitive behavioural therapy can help individuals change their relationship with food.


All medication prescribed for obesity is done so in combination with lifestyle changes to ensure sustained weight loss:

Fat-binding drugs can be prescribed if patients have a BMI>30 or a BMI>28 in combination with other weight-related conditions such as type 2 diabetes or hypertension. These drugs act by preventing the absorption of dietary fat, and can stop up to a third from being absorbed. The excess fat is then excreted by the gut. Appetite suppressants mimic a natural hunger-regulating hormone, glucagon-like-peptide (GLP-1) and can be injected once a week. [11,12]


Weight loss (bariatric) surgery is highly invasive, and involves making changes to the digestive system – examples include fitting a gastric band, joining the top of the stomach to the small intestine (gastric bypass), or removing a section of stomach (partial gastrectomy). They can all lead to substantial weight loss, but have significant risks and are always undertaken in combination with lifestyle changes [13]

Everybody needs to act

Obesity is a complex public health challenge, but it is largely preventable. To ensure the prevalence does not continue to escalate on its current trajectory, it needs everyone to act, at all levels, to tackle the root causes.

The information in this article is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content is for general information purposes only. Always seek the guidance of your doctor or other qualified healthcare professional with any questions you may have regarding your health or medical condition.


  1. World Health Organization. Obesity and overweight. Available at: Accessed March 2022
  2. NHS Digital. Statistics on obesity, physical activity and diet, England, 2020. Available at: Accessed March 2022
  3. The Association for the Study of Obesity (ASO). Introducing World Obesity Day 2022. Available at: Accessed March 2022
  4. World Obesity. World Obesity Day is on the horizon. Available at: Accessed March 2022
  5. Understanding calories. Available at: Accessed March 2022
  6. What is the body mass index (BMI)? Available at: Accessed March 2022
  7. Cancer Research UK. What causes obesity? Available at: Accessed March 2022
  8. 10 leading causes of weight gain and obesity. Available at: Accessed March 2022
  9. Conditions: Obesity. Available at: Accessed March 2022
  10. Office for Health Improvement and Disparities. Adult obesity: Applying All Our Health. Available at: Accessed March 2022
  11. Treatment: Obesity Available at: Accessed March 2022
  12. News: NICE recommends new drug for people living with obesity. Available at: . Accessed March 2022
  13.  NHS. Overview: Weight loss surgery. Available at: Accessed March

Photo Suzanne Brunt Author: Suzanne Brunt BM|
Medical Writer | Porterhouse Medical