Waist-height ratio is 'best test of obesity'

There is more than one way to know whether you’re dangerously fat or not, but put down your calculator as new research suggests that the humble measuring tape is all you need.

Waist to height ratio (WHR) is the best way to predict a person’s risk of serious health problems such as diabetes, high blood pressure and heart disease, according to an analysis presented at the European Congress on Obesity.

Keeping your waist circumference to less than half your height is key to avoiding an increased risk of obesity related diseases, according to author Dr Margaret Ashwell from Ashwell Associates, a scientific consultancy firm.

The simple measurement (waist divided by height) is equally fair to tall and short people so can be used across all countries and ethnic groups. It is a much better predictor of risk than waist circumference on its own, which had already replaced body mass index in medical circles because it acts as a proxy for abdominal fat – a key predictor of heart disease.

Dr Margaret Ashwell, a visiting researcher at Oxford Brookes University, said WHR should be considered by doctors as a one-size fits all screening tool. “Keeping your waist circumference to less than half your height can help increase life expectancy for every person in the world.”

The research analysed data from 31 studies with 300,000 participants. It found WHR to be significantly better than waist circumference and BMI for predicting diabetes, hypertension, cardiovascular disease in men and women from all ethnic groups.

The practical benefits of abiding by this advice can be seen in life expectancy calculations which have been done for the first time by researchers at Cass Business School at City University.

They estimate that a 30-year old non-smoking man could reduce his life expectancy by as much as 14 per cent if his waist to height rations is 0.7 and by as much as a third if it is 0.8.

The National Institute for Health and Clinical Excellence, which produces best practice guidelines for the NHS, is considering whether waist circumference should replace BMI as the recommended screening tool.