Obesity & weight management
Simple steps to understand weight and improve health, with support that lasts.

Mounjaro & weight-loss injections
Your complete guide to dosing, nutrition, side effects and follow-up.
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Weight is part of the picture
Good care considers causes, measurements, and how weight affects your health.
BMI does not directly measure body fat. Measurements and health history guide suitable support. Activity can benefit health even without a large weight change.
Calculate your BMI
Enter your height and weight to see your BMI and its adult category.
Two measurements, one useful starting point.
- Underweight< 18.5
- Healthy weight18.5 – < 25
- Overweight25 – < 30
- Obesity≥ 30
BMI is a screening measure, not a diagnosis. It does not directly measure body fat and can be affected by muscle mass. This adult tool is not for pregnancy or people under 20. About the categories
Where would you like to start?
Understanding obesity and weight assessment
Good care considers causes, measurements, and how weight affects your health.
Habits and treatments that support you
Start with changes you can repeat, then build gradually.
Follow-up and when to seek help
Discuss weight-related difficulties and notice sleep or eating concerns.
Does weight alone tell the whole story of your health?
Choose an answer to see the explanation.
Let's make it clearer.
Does regaining some weight mean treatment has failed?
Weight can return as appetite and energy needs change, or after some treatments stop. Review changes in your habits and treatment with your clinician to support ongoing care.
Is there one diet that suits everyone?
No. Needs, preferences, and health circumstances differ. A balanced eating pattern you can maintain, with support to apply and adjust it, is a useful starting point.
Sources & content information
Source check: 6 September 2026. General patient education for clinician review. Illustrations are conceptual and are not diagnostic images.
- NIDDK: Factors Affecting Weight and Health
- NIDDK: Am I at a Healthy Weight?
- NIDDK: Health Risks of Overweight and Obesity
- NIDDK: Eating and Physical Activity
- NIDDK: Staying Active at Any Size
- NIDDK: Treatment for Overweight and Obesity
- NIDDK: Prescription Medications for Weight Management
- NIDDK: Choosing a Safe and Successful Weight-loss Program
- NHS: Sleep Apnoea
- NIDDK: Symptoms and Causes of Binge Eating Disorder
- CDC: Adult BMI Categories