A piece of string can tell you if your weight is putting your health in danger.

Image: iStock.

Although it’s not without its critics, the Body Mass Index (BMI) is widely perceived as a valid indicator of whether one’s body fat is a threat to their health. But if you don’t have a set of scales, a measuring tape or a calculator nearby, it can be a bit of a hassle to work out.

However, a new study suggests there’s a more accurate way to determine if you’re an unhealthy size, and all you need is your body and a ball of string.

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You simply measure your height with the string — or wool, ribbon, floss, whatever’s handy — then fold it in half and see if it can fit comfortably around your waist. If not, you could be at risk of serious health issues like heart disease. (Post continues after gallery.)

According to researchers at Oxford Brookes University in the UK, this method is superior to the BMI because measuring a person’s waist-to-height ratio takes their abdominal, or visceral, fat into account. For example, someone who isn’t overweight but carries a lot of fat around their middle would pass the BMI test, but not the string one.

This is important, because visceral fat has been linked to a higher risk of cardiovascular disease, type 2 diabetes and metabolic disturbances.

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Almost 3000 people aged 16 and over had their health assessed for the study, which was presented at the European Congress on Obesity in the Czech Republic. Interestingly, the researchers found more than one third of the participants who were classified as “normal” under the BMI formula would have been flagged by the string technique.

The number on the scales can only tell you so much.

“This study not only supports our previous findings on the superiority of waist to height over BMI as a primary screening method for morbidity and mortality risk, but also demonstrates the potentially severe implications of misclassification by BMI alone in screening for heart risk factors," study authors Dr Margaret Ashwell and Sigrid Gibson write.

“Checking that waist-to-height ratio is less than 0.5 could not be simpler: all that is needed is a piece of string, not even a tape measure.”

Will you be trying this one at home tonight?

Tags: bmi , body-fat , health , weight
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