Obesity
Having excess body fat that increases the risk of health problems such as diabetes, heart disease and joint pain.
Quick Summary
Increased body weight and waist size, breathlessness, tiredness, joint pain, snoring and low mood.
Healthy eating, more physical activity and behaviour change; medicines or surgery for some people.
Diet high in calories and processed foods, inactivity, genes, poor sleep, stress and some medicines.
Overview
Obesity is usually measured with body mass index (BMI). For Asian Indians, health risks start at a lower BMI, and waist size is also important.
Even modest weight loss of 5–10% improves blood sugar, blood pressure and cholesterol.
Symptoms
Breathlessness and tiredness
With everyday activity.
Joint pain
Especially knees and back.
Snoring
And sleep apnoea.
Low mood
Weight can affect self-esteem and mental health.
Causes & Risk Factors
Biological Causes
Taking in more energy than the body uses over time, influenced by genes, environment, sleep, stress and medical conditions.
Key Risk Factors
- Diet Sugary drinks, fried and processed foods and large portions.
- Inactivity Desk jobs, screen time and little exercise.
- Medical factors Hypothyroidism, PCOS and some medicines.
Management & Treatment
01. Lifestyle
Balanced meals, smaller portions, fewer sugary drinks and regular activity.
02. Support
Dietitian advice and behaviour change programmes.
03. Medicines or surgery
For some people with very high BMI or related conditions.
Frequently Asked Questions
What is a healthy waist size?
Is BMI accurate?
Are crash diets helpful?
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Obesity(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Overweight and obesity in adults(opens in a new tab) · NHS