It is defined as the narrowest part between the lowest rib and the hip. The waist.
Cut to an everyday scene at the airport: “Didn’t I tell you to put everything on the scanner? Belt, purse, watch, mobile, everything.”
“But sir,” the man in front me in the queue gently mumbled.
“No questions, please follow the airport rules.”
One more journey to the scanner, and he was back, looking nervous. “Raise your hands on to the sides.” He looked like a child playing “aeroplane, aeroplane”.
And that’s when the accident took place. Losing the hold of his hands, his trousers fell. Shrieks from fellow passengers drowned the mumble of an apology from the security officer. His long, oversized shirt saved the day.
Now a bit of history. Lambert Adolphe Jacques Quetelet (1796-1894) lived in Belgium. He was a polymath and genius, and his level of intelligence was considered much ahead of his time. When the French government wanted someone to develop a simple formula to pick out healthy citizens for the purpose of military recruitment, the only person they could think of was Quetelet, and he readily accepted.
He drew proportional diagrams of the human body, from young to old, jotted down their height and weight, and tried to derive a formula to connect them all. After multiple failed attempts, he came up with a simple answer: a ratio of weight in kilogram and height in metres squared, which he called the body mass index (BMI).
Despite his high IQ, Quetelet was poor in biology and did not understand the difference of density between bone, muscle mass and fat. Much later, in an interview, Quetelet was asked the logic of his derived formula. He answered, “Just tried to fit in something.”
Despite BMI being a common measurement of obesity today, we know the caveats. Extremely healthy, muscular men serving in the military have BMI in the abnormal range. A recent meta-analysis shows that 15% of fit American military personnel in active service are obese (BMI > 30kg/m2) and 51% overweight (BMI 25 – 29.9 kg/m2).
The value of waist measurement came to focus in 18th century when women started using corsets. The answer of choosing the right size was to measure the waist and subtract it from the hip (the widest part of the torso below the navel) and the measurement became popular as “hip-spring”. The medical value of waist measurement was triggered by Devendra Singh, an evolutionary biologist from the University of Texas, who theorised that the waist-hip ratio (WHR) was a marker of oestrogen concentration in women. Much later the concept of visceral fat emerged.
Visceral fat (fat around abdominal organs) is different from subcutaneous fat (fat under skin) not just by its distribution (apple shape rather than pear) but by the risk of metabolic diseases. Visceral adiposity implies that the fat is metabolically bad and is resistant to insulin action with a higher likelihood of diabetes.
An abnormal waist-hip ratio (WHR > 0.9 in men and > 0.85 in women) indicate a higher chance of diabetes, high blood pressure, high triglyceride, and a host of metabolic diseases, apart from increased susceptibility to heart attack and stroke.
A simple waist measurement using a measuring tape could reveal not just obesity but presence of a bad metabolically deranged fat. A belt size of more than 90 cm in males and 85 cm in females coupled with a high triglyceride level (a type of fat in blood) makes the prosperous Indian more prone for diabetes and heart disease (Journal of American College of Cardiology, Vol 78, 2021).
While researchers kept their focus on the molecular biology of metabolic markers and epidemiologists were busy splitting hair to find statistically significant indicators of heart disease, no one had the time and common sense to think that the “simple” belt size that we use every day could be a good marker of visceral fat, and consequently heart disease.
Introduced as a functional harness for weapons and accessories, the time-tested “belt” has evolved in our modern world as a tether to hold our trousers below an expanding waistline. The gravity-defying wonder is now turning out to be a simple marker to predict high risk of heart disease.
Take care of your belt size, it could save you from deadly diseases in the long run. Avoiding an airport embarrassment is a bonus.
(The author is a senior cardiologist based in Thiruvananthapuram)
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