BBC Health Correspondent Adam Brimelow shows how body mass index (BMI) is calculated using height and weight measurements.
This standard, used around the world, is based on data from caucasians. People with a BMI of 25 or more are overweight, and those above 30 are obese.
In India these limits have been lowered to 23 and 25, to reflect the risks for their own population. People of Asian origin are more likely than white people to develop heart disease and diabetes.