There had been some suggestion that it may be healthier to be pleasantly plump, but the team at the U.S. National Cancer Institute crushed any such idea with a study of 1.5 million adults published on Wednesday. The healthiest BMI is 22.5 to 24.9, they found -- at the upper end of where the World Health Organization, Centers for Disease Control and Prevention and other groups have said people should be.
Body-mass index is the weight in kilograms divided by the square of the height in meters. A BMI of between 25 and 30 is overweight and a BMI of 30 or over is obese. A person 5 feet 5 inches tall is classified as overweight at 150 pounds (68 kg) and obese at 180 pounds (82 kg). A 5-foot-10 inch (1.8 meter) tall person who weighs 209 pounds (95 kg) has a BMI of 30 and is obese. Being overweight or obese raises the risk of heart disease, diabetes, some cancers and arthritis. The study, published in the New England Journal of Medicine, confirms that having a BMI of 25 or more also makes a person more likely to die than someone the same age who is slimmer.