Obesity a bigger problem than world hunger, Lancet study says
Global overeating has become a bigger problem than world hunger, with more people now obese than underweight, the biggest ever study of worldwide trends in body mass index has revealed.
And it's only going to get worse, the research, published in British medical journal The Lancet on Friday, says.
Over the past 40 years, the number of obese people worldwide has blown out six-fold, from 105 million in 1975 to 641 million in 2014, the study found. Nearly 13 per cent of people worldwide are now obese, compared with just over 9 per cent who are underweight.
"We have changed from a world in which underweight prevalence was more than double that of obesity, to one in which more people are obese than underweight," senior study author Majid Ezzati, from the School of Public Health at Imperial College London, said.
On present trends the world will not meet the target of halting the rise in the prevalence of obesity at its 2010 level by 2025, Professor Ezzati said.
The research also reveals that men are catching up to women in the obesity stakes.
In 1975, women were twice as likely as men to be obese, with 6.4 per cent of women and 3.2 per cent of men recording a BMI of 30 or higher.
But the figure for men has more than tripled to 10.8 per cent over the past 40 years, edging closer to the proportion of obese women, now 14.9 per cent.
Almost one-fifth of the world's obese adults and more than a quarter of the world's severely obese people live in the six high-income countries of New Zealand, Australia, Canada, Britain and the US. Of these, the US has the highest average BMI for both men (28.9) and women (28.7).
Island nations in Polynesia and Micronesia have the highest average BMIs in the world, while East Timor, Ethiopia and Eritrea have the lowest, the study says. In American Samoa the average BMI for women is 34.8 and for men is 32.2. The world's lowest average BMI for women is 20.8 in East Timor; for men, 20.1 in Ethiopia.
Driving the rapid increase in obesity is the changing food environment, Bruce Neal, director of the food policy division at the George Institute for Global Health and professor of global medicine at the University of Sydney, said.
"Incredibly cheap, incredibly unhealthy food has been made available ... everywhere," Professor Neal said.
"If you bathe people in that sort of environment, they will become obese."
By 2025, roughly a fifth of women (21 per cent) and men (18 per cent) worldwide will be obese on current projections, the study says.
Left unchecked, obesity will "bankrupt our already overwhelmed healthcare systems", David Crawford, Alfred Deakin Professor and co-director of the Institute for Physical Activity and Nutrition at Melbourne's Deakin University, said.
What is needed is government action "on a scale that has never been contemplated before", Professor Neal said.
Educating individuals in personal responsibility will not be enough, he said, because public health campaigns can't compete with the "many, many millions more dollars" the food industry spends on an "absolutely contrary" message to maximise its profits.
Subsidising healthy foods and taxing or restricting the sale and promotion of unhealthy foods were more effective ways of changing food industry behaviour, Professor Neal said.
Earlier this month, the British government announced it would introduce a sugar levy on soft drinks from 2018, prompting celebrity chef Jamie Oliver to urge Australia to "pull your finger out".
Fizzy, sugary drinks are "a very easy, obvious target" because over-consumption of sugar is the main driver of Australia's "enormous problem" with obesity, including childhood obesity, Professor Neal said.
The consumption of sugar-sweetened soft drinks has increased by 30 per cent over the past 10 years in Australia, the Victorian Department of Health's Better Health website says. The standard serving size for soft drinks has also increased from 375ml cans to the 600ml bottles commonly sold today. Just one such bottle of soft drink exceeds the recommended energy intake from refined sugar for an average 14-year-old girl.
Professor Jennie Brand-Miller, director of the Glycemic Index Research Service at the University of Sydney, said the study's most interesting finding was that there was virtually no increase in the BMI of women in Belgium, France and Switzerland - countries associated with with good chocolate, cheese and wine.
"We need to study them carefully - the women, not the chocolate - and learn from them", she said.
The BMI is imperfect as a measure of healthy body weight in individuals and some groups because it does not recognise different body compositions by differentiating between body fat and muscle mass. But on average over large populations, it is a "pretty good" measure, Professor Neal said.
The Lancet study analysed pooled data from 1698 population-based studies totalling 19.2 million men and women aged 18 and over from 186 countries covering 99 per cent of the world's population.