The most widely used method to assess a person’s weight is the body mass index (BMI), which is your weight in kilograms divided by your height in metres squared.

If your BMI is:

• between 25 and 29, you would be considered overweight
• between 30 and 40, you would be considered obese
• over 40, you would be considered very obese

Another useful method is to measure around your waist. Men whose waist measurement is 94 cm or more and women whose waist measurement is 80 cm or more are more likely to develop obesity-related health problems, such as type 2 diabetes, heart disease and some types of cancer.

As obese children also tend to be obese in later life, it is important for parents to set the right example for their children from an early age.

If you think you may be overweight or obese

If you are overweight or obese, visit your doctor to find out if you are at increased risk of health problems, and how you can safely lose weight.

Things to talk to your doctor about include:

• any underlying causes for your obesity – for example, if you are on certain medicine or have a medical condition that causes weight gain
• your lifestyle – particularly your diet and how much physical activity you do, and also whether you smoke, and how much alcohol you drink
• how you feel about being overweight – for example, if you are feeling depressed about it
• how motivated you are to lose weight
• your family history of obesity and other health conditions, such as diabetes (a condition caused by too much glucose in the blood)

As well as calculating your BMI, your doctor may also perform tests including measuring your blood pressure, the distance around your waist, as well as glucose (sugar) and lipid (fat) levels in your blood.