More people around the world are now obese than underweight, and, by 2025, it’s predicted that one fifth of adults worldwide will be obese.
Even more concerning is the rise in levels of childhood obesity. Experts in early childhood development now know that poor health in the very early years can dramatically, and sometimes irreversibly, hinder full and healthy development.
But where is childhood obesity on the rise?
In the US, nearly a quarter of children are obese
Since the 1970s, the proportion of obese children in G20 countries has ballooned.
Data collected for a report into worldwide obesity from 1975-2016 by The Lancet shows that in the US — which remains the leading country for childhood obesity — the rate of obesity in boys aged 5-19 has more than quadrupled from 5.5% to 23.3%. For girls, the rise was slower, but also significant, tripling from 5.6% to 19.5%.
The report, which defines obesity as more than two standard deviations above the median of the WHO BMI growth reference for children and adolescents, shows that nearly one quarter of boys and one fifth of girls in the US are obese. But while the growth rate in the US has now flattened, the fastest increases have occurred elsewhere: in Asia and Africa. Between 1990 and 2016, the proportion of obese girls and boys in China increased by a factor of 20, to 7.1% of all girls and 15.4% of boys.
In South Africa, the increase has been even starker. There, the childhood obesity rate increased by a factor of 23 between 1990 and 2016 for girls and 49 for boys. In comparison, in the UK, the incidence of childhood obesity among girls increased by a factor of 1.5 and doubled for boys.
But what happens in early childhood?
The first five years of a child’s life are now seen as crucial for their later development.
Unfortunately, data on childhood obesity in the early years harder to come by than for the ages 5-19. Individual countries tend to measure at different ages. The UK surveys children in the reception class, all between the ages of four and five, while the US assesses children aged two to five, and Australia two to four. They also all use a subtly different definition of what obesity is. This makes comparison difficult. Nevertheless we can see that, even with the youngest children measured included in the range, the proportion of young children in the US who are obese is nearly 14%.
In comparison, in South Africa the proportion of 2-5 year olds who are obese is 4.7%. In Australia, the proportion of obese 2-4 year olds is 8.7%, and in the UK, the proportion obese 4-5 year olds is 9.6% of all children. In this limited comparison at least, countries in the global north show higher incidences of obesity in early childhood than the global south.
Obesity is plateauing in high income countries
So what’s happening? As the Lancet report points out, in high income countries, obesity is now plateauing, while in Asian countries, and South Africa, it has accelerated.
A recent report by Chinese researchers suggests that this is a result of the adoption of western lifestyles in China. As average wealth increases, and families becoming more affluent, they are eating more convenience food and reducing their physical activity.
Meanwhile, though levels of childhood obesity remain high in high income countries, they appear to be stabilising. The challenge for policymakers now is how to push these levels back the other way.
There are promising signs they are beginning to get to grips with it. In the UK, government is beginning to think about how behavioural insights could help design better ways to promote healthy choices for young children, while in Amsterdam a new scheme sees nurses visit expectant mothers in the home to advise on healthy diets, exercise and their impact on child growth. In many cities, child-friendly design advocates emphasise the importance of design to help promote play, which can have a big impact on childhood obesity. — Anoush Darabi