Your waist should measure less than half your height, UK health officials say in new guidelines for preventing diabetes and hypertension

• New UK guidance encourages people to calculate their waist to height ratio to gauge health.
• Keeping your waist measurement less than half your height may help prevent various risks associated with obesity, UK health officials say.

UK health officials say maintaining a waist measurement that is half your height can benefit health.

In new guidelines issued by the UK National Institute for Health and Care Excellence (Nice), people with a BMI under 35 (30-39.9 is classified as obese), in particular, have been encouraged to monitor their abdominal fat. Just BMI alone has long been considered an imperfect way to assess whether someone is a healthy weight.

Having more fat around the abdomen is linked to higher risk of diabetes, type 2 diabetes, high blood pressure, heart disease, and stroke.

By measuring waist to height ratio as well as BMI, doctors say people will be better able to gauge their health risks.

"Our updated draft guidelines offer people a simple and effective way of measuring their weight so they can understand the factors that could impact their health and take action to address them," Dr. Paul Chrisp, director for center for guidelines at Nice, said in the organization's press release.

How to measure your waist

A healthy waist to height ratio is 0.4-0.49, meaning no increased health risks, according to Nice. A ratio of 0.5-0.59 puts people at increased risk, and a ratio over 0.6 means the highest risk.

If you are, for example, 178cm (5'10") tall, your waist should be under 89cm (35").

The guidance says that to measure your waist, you should find the bottom of your ribs and the top of your hips, wrap a tape measure around the waist midway between these points, and breathe out naturally before taking the measurement.

Following evidence that suggests some Black, Asian and minority ethnic groups are more prone to central adiposity (stomach fat) and have an increased cardiometabolic risk at lower BMIs, Nice lowered the BMI thresholds for those ethnic groups.

Waist to height ratio is not accurate for those with a BMI over 35 (obesity classes 2 and 3), children under two, or pregnant women, according to Nice.

Doctors use various measurements to assess risks associated with obesity

Dr. Spencer Nadolsky, a US obesity specialist physician, told Insider that waist to height ratio is one of a few markers that approximate abdominal adiposity (fatness).

"Abdominal obesity/fat is a risk factor for all of the metabolic consequences of obesity," he said.

If you have a BMI between 30-35 but most of your weight is on the legs and hips, it may actually protect against some metabolic consequences such as hypertension, type 2 diabetes, and dyslipidemia, which are all big risk factors for cardiovascular disease and stroke, Nadolsky said.

Waist circumference alone or waist to hip ratios are other measurements some health professionals recommend, but no one measurement is perfect, according to Nadolsky.

"The guidance isn't bad or wrong," he said. "It may help with some who struggle with weight loss in general, so maybe focusing more on body recomposition with exercise, where the scale doesn't change but the inches do, may be helpful for some."

28% of adults in England are obese and a further 36% are overweight, according to The 2019 Health Survey for England.

In the US, 36.5% of adults have obesity, and a further 32.5% are overweight, according to the CDC and the National Institute of Diabetes and Digestive and Kidney Diseases respectively.