Nifty ways to cleave your blubber

PUBLISHED : Tuesday, 28 February, 2012, 12:00am
UPDATED : Tuesday, 28 February, 2012, 12:00am

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By the end of 2015, the World Health Organisation predicts that the planet will have approximately 2.3 billion overweight people aged 15 years and above, of whom more than 700 million will be obese.

That's a scary statistic, first because children (who are becoming increasingly overweight) are not included in the figures, and second because it means, mathematically, that two out of five people are likely to be overweight.

Hongkongers reportedly reached that rate in 2010, although the age range surveyed by the government was different. Among adults aged 18 to 64, 21.7 per cent were obese, and another 18.7 per cent were overweight.

Body mass index (BMI), which is calculated by dividing the person's weight in kilograms by their height in metres squared, is the standard. So, for example, a 1.67-metre-tall person weighing 61kg would have a BMI of 21.9, which is in the normal range (18.5 to 22.9). A BMI of 23 to 24.9 is considered overweight; 25 or above is obese.

But the scale is not the only indicator of weight. The Health Department recommends a combination of BMI and waist circumference to establish the clinical measurement of being overweight or obese. A bodybuilder would have the weight, but also a slimmer waistline, because muscles are denser and take up much less volume than fat. Lean body mass is also metabolically active and needs more calories to maintain.

A large waist indicates fat around the heart, kidneys, liver and pancreas. If the waistline is growing, so is the risk of developing chronic diseases.

For Asian adults, the point at which this increased risk kicks in is at a waistline of 90cm or above for men and 80cm or above for women, according to the WHO's Western Pacific Regional Office. This does not apply, however, to those under 18 and pregnant women.

The steps to successful weight control have been preached many times: keep a balanced diet, get regular physical activity, ensure safe weight loss (0.5kg to 1kg per week), and seek advice from professionals for an individually tailored and monitored programme.

But what about 'contagious' weight loss? Researchers at Brown University in the US suggest that shedding pounds can have a ripple effect. The study, published online in the journal Obesity, is the first to examine the effectiveness of an online, team-based weight-loss competition.

The researchers looked at the results of the 2009 Shape Up Rhode Island campaign, a 12-week statewide competition that included 3,330 overweight or obese individuals representing 987 teams of between five and 11 members each. Participants who lost at least 5 per cent of their initial body weight tended to be on the same teams. Those who reported higher levels of teammate influence increased their odds of achieving this level of weight loss by 20 per cent.

Lead author Dr Tricia Leahey of Miriam Hospital and Alpert Medical School at Brown says the findings show 'teammates influenced each other, perhaps by providing accountability, setting expectations of weight loss, and providing encouragement and support'.

'We're all influenced by the people around us, so if we can harness this positive peer pressure and these positive social influences, we can create a social environment to help encourage additional weight loss.'

Perhaps it's time for the Health Department to start a similar city-wide weight-loss competition with some attractive prizes for winners. Preaching can go only so far.