Many doctors now believe that when it comes to your health, your waist measurement is important.
While body mass index (BMI) is a good way to decide if you're overweight, it doesn't tell the whole story.
BMI is a measure of how healthy your weight is for your height and gender. You can work out what your BMI is by using our healthy weight calculator.
If you have a high BMI, you're likely to be carrying extra fat. But your health could be at greater risk depending on where you store that fat.
Having a large amount of tummy fat (compared with fat around the bottom or thighs) makes you more likely to develop diabetes and heart problems.
A healthy waist circumference for men is less than 94cm and for women it's less than 80cm.
Losing weight and keeping it off isn't easy, but it has many benefits and you may only need to make small changes to your lifestyle to maintain a healthy weight.
Why lose weight?
Obesity causes 9,000 premature deaths in England every year, and on average reduces life expectancy by nine years.
It's also linked to serious health problems including an increased risk of type 2 diabetes, heart disease and cancers of the breast, colon and prostate.
Most people who are overweight can blame their excess weight on eating more calories than they burn.
That means there are two main options if you want to lose weight: eat less or do more physical activity. The best way to lose weight is a combination of the two.
Weight loss tips
The good news is that you can help reduce your risk of obesity-related health problems by losing weight through eating more healthily and taking more physical activity.
You can find a host of articles to help you with all aspects of attaining a healthy weight in the Lose weight section.
See how you can cut down on calories by making simple changes to your everyday diet in Healthy food swaps.
It's not just small changes to your eating habits that can make a big difference. Getting more physical activity also helps you to shed the pounds, and you can do it in just three short bursts each day with these Ten-minute workouts.
Even if you're well on the way towards your target weight, there are always danger zones that leave you tempted to overindulge. See our tips on how to avoid the Diet danger zones.
One excuse for choosing a fat-laden quick-fix supper is that healthy eating is expensive. Read about how to save pennies as well as calories in Eat well on the cheap.
Two-thirds of dieters regain all the weight they've lost within four years. For advice on how to stop piling back on the pounds read Lose weight for life.