Why the war on childhood obesity is failing

SUZIE JIMENEZ cried as she waited in the car park. Her 14-year-old son was in the emergency department, suffering from stomach pains. He felt humiliated when doctors in Austin, Texas, told him that because of his bigger body he would need to have a CT scan rather than an ultrasound. He was scared to tell them he weighed 360 pounds (163kg). A shortage of Wegovy had meant that despite being approved for the weight-loss drug, he had not yet been able to start it. Ms Jimenez, at times the sole breadwinner for her family of five, says they sometimes ate fast food for “comfort”.

Obesity is one of the world’s most serious public-health crises. It increases the risks of developing diabetes, heart disease, stroke and some cancers. Since 1990 global rates have doubled among adults and quadrupled among children. Today more than 1bn people, including 7% of girls and 9% of boys, are classified as obese (see chart). In 2019 it led to around 5m deaths, 20 times as many as malnutrition did. Obesity is no longer just a rich-world problem. Childhood rates are highest on the islands of the Pacific and the Caribbean, and rising fastest in developing countries such as Cambodia and Lesotho.

Most of the economic costs of obesity are borne by individuals, who take more time off work or miss more days of school, and are more likely to be low-paid or unemployed. Obese children are more often targets for bullies, too. But the burden on the state is also considerable. Last year the Institute for Fiscal Studies, a British think-tank, estimated the annual costs of overweight and obese adults through health-care expenditures, formal social care and inactivity at work, excluding those individual costs (which most studies do not). Even after discounting the grisly “savings” from related deaths, they amounted to about £32bn ($41bn), or 1% of Britain’s GDP.

Although telling adults what to eat and when to move can be seen as interfering, governments should try to prevent children becoming obese and encourage their weight-loss efforts. Early interventions could reap benefits later: children with obesity are five times more likely to be obese as adults than their slimmer peers. The trouble is, nobody knows how best to go about it. No country has ever managed to reduce obesity; the more successful ones have merely stemmed it. The problem is too complex to be solved by simple public-health measures or obesity drugs alone. The hunt is on to find evidence for interventions that work together, and quickly.

Behind rising obesity rates lies a mix of biological, economic and social factors. Much of the world is awash with highcalorie foods even as many people live sedentary lives. No single nutrient or food group is to blame, but items containing high proportions of refined wheat, sugar and vegetable oils are under the spotlight. Highly processed foods, which are widely accessible and relatively inexpensive, are the ultimate example.

At the same time, even in rich countries, many neighbourhoods lack fresh, healthy alternatives. In Texas the Department of Agriculture estimates that one in five people live in poor areas with limited access to nutritious foods. Children from such places are more likely to be obese than those from richer ones. Processed foods are convenient, take much less time to prepare and—calorie for calorie—work out cheaper, explains Samir Softic, a specialist in fatty-liver disease at Kentucky Children’s Hospital. His state has the second-highest rate of childhood obesity in America after West Virginia. It also has the second-highest number of fast-food outlets per person.

The evolution of the human body is another important factor. Losing weight is not simply a matter of reducing one’s calorie consumption. The body adapted to survive famines, not feasts, so it clings onto weight it gains. It then resists the loss of fat by reducing the amount of energy it needs to survive and by increasing hunger signals; it will fight to regain the lost weight for years. This is why most long-term efforts at significant weight loss fail.

Keeping track of trends is difficult. Body-mass index (BMI), which divides a person’s weight (in kilograms) by the square of their height (in metres), is fine as a common measure of obesity for most adults but inaccurate for brawny types, since it cannot distinguish between fat and muscle. It is not helpful in children, whose bodies are growing and changing. Boffins from the World Health Organisation consider a child obese if his or her BMI is more than two standard deviations above the median for their age using a model from 2007 as a reference—an imperfect measure. Experts also consider increases in associated childhood diseases. Globally, the age-standardised incidence rate of type-2 diabetes has jumped by 57% in 15- to 19-year-olds over the past 30 years.

Governments looking to cut childhood obesity have few models to draw on. Start in Amsterdam, which once seemed to have a smart strategy. The Dutch capital received international plaudits when rates of overweight and obese children fell from 21% to 18.5% between 2012 and 2015. The local government sought to change individual behaviour: it provided nutrition classes for parents and children in poor neighbourhoods, put children on care plans, offered free sports such as ice-skating and discouraged junk food in schools. But the results did not last. Rates ticked up slightly to 18.7% in 2017; then the municipality stopped publishing them.

Then there is Chile, where over half of 4- to 14-year-olds are overweight or obese. In 2016 the government slapped black warning labels, shaped like stop signs, on the front of packaged foods high in calories, sugar, saturated fat and salt. Eight other countries have since copied the move. Chile also introduced strict bans on the marketing of these foods to under-14s, and a programme of exercise and nutrition in schools. Despite all this, a study published this year in the Pan-American Journal of Public Health showed no change in prevalence rates in the three years after the legislation was enacted. (Professor Camila Corvalán, an adviser to the Chilean government on the scheme, cautions that it is too early to draw conclusions.)

Now consider Britain, which has experimented with a sugar tax of sorts. Its levy on sugar-sweetened drinks, implemented in 2018, has had mixed success. Big brands reformulated their products to avoid it, resulting in a drop in sugar consumption of 4.8g per day among children. Researchers at the University of Cambridge found a slight reduction in obesity rates among 10- to 11-year-old girls, though not in younger children or 10- to 11-year-old boys, who consume more of the beverages.

Selective taxes “can sometimes not give you the right outcomes”, argues Chris Hogg, global head of public affairs at Nestlé, the world’s largest food and drink company. For the best public-health outcomes, he reckons, it is better to have room for policies and guidance “to steer [the industry] in the direction that policymakers think makes most sense”. Such guidance has long been standard practice in places such as Britain. The drinks levy aside, all other industry measures to reduce childhood obesity in Britain have been voluntary and largely unsuccessful.

So what to try next? Most health professionals and policymakers argue that current measures do not go far enough. Public-health experts are trying to pull together a guide to sugar taxes. In the 70-odd countries where taxes on sweetened drinks have been tried, the biggest impacts were felt in poorer countries such as South Africa, where consumers are more sensitive to price changes. Some now want to broaden taxes to stop people shifting to other unhealthy products. Last year Danone, a big dairy company, called for a wider tax on foods that are high in fat, salt and sugar, arguing that regulation is the only way to get firms to make their products healthier.

Critics of sugar taxes and their ilk say they are regressive. Because the poor spend a higher share of their income on food, and so are more likely to buy cheap, highly processed items, they are also more likely to be hit by additional levies on them. To offset this, Barry Popkin of the University of North Carolina is working with countries in Latin America and Africa to develop subsidy regimes for fruit and vegetables. He reckons that warning labels with pictures on junk food, like the ones on cigarette packets, will be tried next.

Obesity drugs are another tool attracting attention. The market for GLP-1 medications such as Wegovy is expected to reach $100bn a year by 2030. But they cannot be the main solution for the world’s obese people: they cost too much. Jonathan Gruber, an American economist, reckons that buying them for the 40% of Americans with obesity would cost about $1trn a year, or roughly 4% of America’s GDP.

The price will probably drop eventually. But even then, many adults and youngsters will not want to take GLP-1 drugs. They cause side-effects such as nausea; one study found that after one year, just 32% of patients were still taking them. There are also growing concerns over rare side-effects such as pancreatitis and intestinal obstructions. Yet sustained use of these drugs is needed to keep the weight off, along with diet and lifestyle changes to maximise health.

Measured approach

Where else is there to turn? Japan offers a glimpse of how influential cultural mores can be. “As a whole, Japanese people are very health-conscious,” says Yokote Koutaro of the Japan Society for the Study of Obesity. Japanese diets have become more Westernised over the years, but people still eat traditional food, which tends to be fresh and is often relatively healthy. They also eat modest portions. Take McDonald’s, says Mr Yokote. If you order a large-size drink in Japan, you slurp less than if you ordered a “small” one in America.

Social norms and government nudges seem to be working. Japan lacks strict rules on labelling or advertising fatty foods. But its cities are walkable, and even convenience stores often stock nutritious options such as salads. The government has long required schools to serve balanced lunches. Its other interventions are sometimes intolerably nannyish: in 2008 it told companies to start measuring the waistlines of their employees.

There will be no single solution to fighting obesity in children. Taxes, regulation and obesity drugs will play a part, as will consumers. Governments need to evaluate interventions over the long term. The goal should be to ensure that making healthy choices is far easier than the alternative. The problem is getting there. ■