Introduction

The term 'obese' describes a person who's very overweight, with a lot of body fat.

It's a common problem around the world that's estimated to affect around one in every four adults and around one in every five children aged 10 to 11.

Defining obesity

There are many ways in which a person's health in relation to their weight can be classified, but the most widely used method is body mass index (BMI).

BMI is a measure of whether you're a healthy weight for your height. You can use the BMI healthy weight calculator to work out yourscore.

For most adults, a BMI of:

• 18.5 to 24.9 means you're a healthy weight
• 25 to 29.9 means you're overweight
• 30 to 39.9 means you're obese
• 40 or above means you're severely obese

BMI isn't used to definitively diagnose obesity, because people who are very muscular sometimes have a high BMI without excess fat. But for most people, BMI is a useful indication of whether they're a healthy weight, overweight or obese.

A better measure of excess fat is waist circumference, which can be used as an additional measure in people who are overweight (with a BMI of 25 to 29.9) or moderately obese (with a BMI of 30 to 34.9).

Generally, men with a waist circumference of 94cm (37in) or more and women with a waist circumference of 80 cm (about 31.5 in) or more are more likely to develop obesity-related health problems.

To do this you should:

• eat a balanced, calorie-controlled diet as recommended by your GP or weight loss management health professional (such as a dietitian)
• join a local weight loss group
• take up activities such as fast walking, jogging,swimming or tennis for 150 to 300 minutes (two-and-a-half to five hours) a week
• eat slowly and avoid situations where you know you could be tempted to overeat

You may also benefit from receiving psychological support from a trained healthcare professional to help change the way you think about food and eating.

If lifestyle changes alone don't help you lose weight, a medication called orlistat may be recommended. If taken correctly, this medication works by reducing the amount of fat you absorb during digestion. Your GP will know whether orlistat is suitable for you.

In rare cases,weight loss surgery may be recommended.

It's estimated that obesity and being overweight contribute to at least1 in every 13 deaths in Europe.

Outlook

There's no "quick fix" for obesity. Weight loss programmes take time and commitment, and work best when fully completed. The healthcare professionals involved with your care should provide encouragement and advice about how to maintain the weight loss achieved.

Regularly monitoring your weight, setting realistic goals and involving your friends and family with your attempts tolose weight can also help.

Remember that even losing what seems like a small amount of weight, such as 3% or more of your original body weight, and maintaining this for life, can significantly reduce your risk of developing obesity-related complications like diabetes and heart disease.