Information about obesity
Reliable information can help people understand obesity, make informed choices and find appropriate support. Obesity is a complex health condition influenced by a range of factors. It is not simply a matter of willpower, and people affected by it deserve care and respect without judgement.
What is obesity?
Obesity describes having excess body fat that may affect health. In adults, body mass index (BMI) is sometimes used as an initial screening measure. It compares a person’s weight with their height, but it does not directly measure body fat and may not be suitable for everyone. A health professional can help interpret BMI alongside other factors, such as medical history and overall wellbeing.
What can contribute to obesity?
Body weight is affected by many interacting influences. These may include genetics, health conditions, medicines, sleep, stress, mental health, food availability, income, culture and the environment in which someone lives. Eating habits and physical activity can also play a part, but they are only pieces of a much bigger picture.
This is why there is no single approach that works for everyone. Effective support takes account of a person’s health, circumstances and preferences.
Why does it matter?
For some people, obesity can increase the likelihood of developing health problems, including type 2 diabetes, heart disease, high blood pressure and certain types of cancer. It can also affect mobility, sleep and emotional wellbeing. These risks vary between individuals, and a person’s weight alone does not provide a complete picture of their health.
Finding trustworthy information and support
Look for information from recognised health services and qualified professionals. Be cautious of claims promising rapid or guaranteed weight loss, extreme diets, or products that say they can treat obesity without proper evidence. If you have concerns about your weight or health, speak with your GP or another qualified healthcare professional. They can discuss suitable options and refer you to additional support if appropriate.
Support may include help with nutrition, physical activity, sleep, mental wellbeing or an underlying health condition. For some people, a clinician may also discuss medicines or specialist services. Any plan should be safe, realistic and tailored to the individual.
A respectful approach
People’s experiences of weight and health are different. Stigma and blame can make it harder to seek care, so conversations should be compassionate and focused on a person’s needs rather than assumptions about their lifestyle. Small, sustainable changes may be more manageable than drastic measures, and progress can mean improvements in wellbeing and health—not only a change on the scales.
This article provides general information and is not a substitute for medical advice, diagnosis or treatment. Speak to a healthcare professional about your own circumstances.
Understanding Obesity: Answers to 9 Common Questions
- What is obesity and how is it defined?
- What factors can contribute to obesity?
- How is obesity measured in adults?
- Can BMI provide a complete picture of someone’s health?
- What health conditions are associated with obesity?
- Where can I find reliable information about obesity?
- What support is available for people concerned about their weight?
- How can I tell whether weight-loss advice is safe and trustworthy?
- How can I talk about obesity without stigma or judgement?
What is obesity and how is it defined?
Obesity is a complex health condition involving excess body fat that may affect a person’s health and wellbeing. In adults, it is often identified using body mass index (BMI), which compares weight with height; a BMI of 30 or above is commonly classified as obesity. However, BMI is a screening measure, not a diagnosis, and does not directly measure body fat or account for factors such as muscle mass, age or ethnicity. A healthcare professional can interpret it alongside other information to provide a fuller assessment.
What factors can contribute to obesity?
Obesity can be influenced by a combination of factors, and there is no single cause. These may include genetics, health conditions, certain medicines, sleep and stress, as well as eating patterns, physical activity and access to affordable, nutritious food. A person’s income, work, family life and local environment can also affect their health and daily choices. Because these influences vary from person to person, support should be compassionate and tailored to individual circumstances.
How is obesity measured in adults?
In adults, obesity is commonly assessed using body mass index (BMI), calculated by dividing weight in kilograms by height in metres squared. BMI can indicate whether someone’s weight may affect their health, but it is a screening tool rather than a diagnosis: it does not directly measure body fat and may be less reliable for some people, including those with high muscle mass or from certain ethnic backgrounds. A healthcare professional may consider BMI alongside waist measurements, medical history and other health factors.
Can BMI provide a complete picture of someone’s health?
No. BMI can be a useful screening measure, but it does not directly measure body fat or show where fat is carried, and it may not reflect differences in muscle mass, age, ethnicity or overall health. A healthcare professional will consider BMI alongside other factors, such as medical history, waist measurement, symptoms and wellbeing, to build a more complete picture.
What health conditions are associated with obesity?
Obesity is associated with a higher risk of several health conditions, including type 2 diabetes, high blood pressure, heart disease, stroke, sleep apnoea, osteoarthritis and some types of cancer. It can also affect mental wellbeing and increase the risk of fatty liver disease. These risks vary from person to person, and weight alone cannot determine an individual’s health. If you have concerns, speak to your GP or another qualified healthcare professional for advice tailored to you.
Where can I find reliable information about obesity?
Reliable information about obesity is available from the NHS, the UK Health Security Agency and other recognised health organisations. For advice that takes your personal circumstances into account, speak to your GP or another qualified healthcare professional. Be cautious of websites or products promising quick fixes, guaranteed weight loss or treatments without credible evidence.
What support is available for people concerned about their weight?
If you’re concerned about your weight, support is available through your GP, who can discuss your health, answer questions and help you find suitable next steps. Depending on your needs, this may include advice on nutrition, physical activity, sleep or emotional wellbeing, or a referral to a dietitian or specialist service. Support should be respectful and tailored to your circumstances; be cautious of quick-fix diets and speak to a qualified health professional before making major changes.
How can I tell whether weight-loss advice is safe and trustworthy?
Look for weight-loss advice from recognised health services or appropriately qualified healthcare professionals, and check whether it is supported by reliable evidence. Trustworthy guidance is realistic, considers individual health and circumstances, and does not promise rapid results or guaranteed outcomes. Be cautious of extreme diets, pressure to buy supplements or treatments, and claims that one method works for everyone. If you are unsure whether advice is suitable for you, speak to your GP or another qualified healthcare professional.
How can I talk about obesity without stigma or judgement?
Talk about obesity with sensitivity, respect and an understanding that it is a complex health condition influenced by many factors—not simply personal choices or willpower. Use neutral, person-first language, such as “a person living with obesity”, and avoid labels, blame, assumptions or comments about someone’s body. Listen to how people describe their own experiences, ask permission before discussing weight, and focus on wellbeing and the support someone wants rather than appearance.