A BMI of 18 to 25 is considered a healthy weight, 25 to 30 is overweight, and over 30 is obese. But amid increasing concerns over the toll of obesity on the health of the population in England and Wales, for the first time ever, the National Institute for Health and Care Excellence Nice will say on Friday that adults with a BMI under 35 should also measure their waist-to-height ratio to stay healthy.

By using the ratio together with BMI, people can work out whether they are carrying excess fat around their middle, which is known to raise the risk of serious conditions, including type 2 diabetes, high blood pressure and heart disease.

Anyone wanting to find out their waist-to-height ratio can use an online calculator, or could ask a health professional to work it out for them. To measure their waist, they should find the bottom of their ribs and the top of their hips, wrap a tape measure around the waist midway between these points and breathe out naturally before taking the measurement.

As an example, a cm 5ft 4in female with a waist circumference of 74cm 29in would have a healthy ratio, but 81cm would push her into the unhealthy range. A man who is cm 5ft 10in would be at increased health risks if he had a 91cm 36in waist.

The guideline says a healthy waist to height ratio is 0. A ratio of 0. The guidance also sets out ways to assess childhood obesity and says tailored plans should be considered for children with a high BMI or a waist-to-height ratio above 0.

It was invented before calculators, when a formula had to be very simple, he wrote. As such, abdominal fat is linked to a higher risk of cardiovascular disease, Type 2 diabetes, and breast cancer in women.

They reached this conclusion after measuring actual body fat and composition in 81 people using a highly precise total body scanner, then comparing the results with those of various anthropometrics commonly used to predict body fat and obesity, including BMI, WHtR, waist-to-height ratio 0.

Relying on the BMI alone, only one in seven of the participants would have been classified as obese in terms of their whole body fat, whereas according to the WHtR, the more accurate figure of one in two, or half the participants would meet that threshold.

WHtR was also a closer proxy for measuring abdominal fat in both men and women. The waist-to-hip ratio was the weakest formula of the bunch.

The study, led by Michelle Swainson , a professor of exercise physiology, found the cutoff for predicting whole body obesity was 0. That number could be even lower. In separate research, Margaret Ashwell, a senior visiting fellow at City University London, has discovered through several studies— including a meta-analysis of 44 studies in adults and 13 in children—that the risk of developing diabetes and cardiovascular disease begins to rise with a WHtR above.

Her research also found that the WHtR measurement is more precise at measuring life expectancy. It also beats the BMI and waist circumference matrix some doctors rely on. With a piece of string, a person can measure their height, then fold the string in half and check to see whether it fits around their waist.

A person who is six feet tall 72 inches; centimeters should keep his or her waist below a trim 36 inches or 91 centimeters. She calls the body shape below the.