Waistline warning we need to take seriously

When it comes to waistlines, it seems we can win the battle of the bulge, but not necessarily the war. Take the advice of health officials to keep midriffs within 36 inches (91cm) for men and 32 inches (81cm) for women to ward off obesity-related illnesses. Even if you pass this test, researchers at the University of Hong Kong medical faculty say this may not be trim enough to prevent fatty liver disease, a precursor to liver cancer or cirrhosis. They recommend amending the guidelines to 33 inches for men and 29 for women.

If we are medically obese, even if we do not look particularly fat, we are at greater risk of other problems such as diabetes, heart disease and hypertension. The clinical focus on waistlines is because they are an indicator of central obesity, or fat around the tummy, which is most associated with increased risk. How it is defined can vary depending on sex, age and culture. Some studies try to smooth out these factors by adopting a waist-to-hip ratio, where the circumference of the waist is divided by that of the hips. According to some studies, the optimum ratio is about 0.7 for women and 0.9 for men.

The HKU study examined the livers of nearly 2,500 healthy non-drinkers with an average age of 44 who tested negative for hepatitis B and C. More than 40 per cent were found to have non-alcoholic fatty liver disease. That contradicts traditional western wisdom that the disease is caused by alcohol and hepatitis C. Researchers found that waistlines, rather than body-mass index, used most to test child obesity, were the most accurate pointer to non-alcoholic fatty livers.

Back to the battle of the bulge and the new front in the war. HKU researchers say the enemy comprises the usual suspects: poor diet, lack of exercise and stress. Hong Kong women may have the world's longest life expectancy, and men close to it. But we should reflect on diets that are becoming more westernised, a lack of emphasis on sport and exercise from an early age, and this fast-paced city's lack of work-life balance.