For more than 30 years we have been wedded to the Body Mass Index (BMI) as the sole criterion for deciding whether someone is obese or not. It is used by most health authorities to classify both adults and children as overweight and obese in order to qualify for dieting advice, activity programmes, even bariatric surgery and to assess the risk of diabetes.
But some experts have criticised the BMI as a flawed system, which doesn't take into account whether a person is actually carrying more fat, or just more weight. Here's how to calculate your BMI, as well as other indicators that you might want to watch your weight.