Something striking just happened in global nutrition: As of 2025, children worldwide are now more likely to be obese than underweight.
According to UNICEF’s new Child Nutrition Report, about 9.4 percent of school-age kids (ages 5–19) are living with obesity, compared to 9.2 percent who are underweight. Twenty-five years ago, the gap was much wider: Nearly 13 percent of kids were underweight, while just 3 percent had obesity. Over time, those lines have converged and flipped.
It might feel odd to put obesity in the same bucket as underweight; one has long been seen as a problem of scarcity, the other of excess. But public health experts now define both as forms of malnutrition, which they describe in three dimensions: not enough food, too much of the wrong food, and hidden hunger from micronutrient deficiencies.
There’s a silver lining in this crossover: Fewer kids are dangerously thin than two decades ago. That decline really matters, because being underweight can mean stunted height, impaired brain development, weak immunity, and in worst cases, a higher risk of death. So, the fact that those numbers are falling is genuine progress.
But it’s overshadowed by how quickly obesity has surged, with 188 million children now living with it — though where it shows up most varies widely by region.
Obesity in children isn’t just about size; it raises risks for Type 2 diabetes, high blood pressure, cardiovascular disease, and even certain cancers later in life. Starting so young makes the costs even higher. By 2035, being overweight and obesity are expected to drain more than $4 trillion a year globally — about 3 percent of the world’s GDP.
UNICEF bases that 2025 crossover on projections from survey data through 2022, and while the precise year carries some uncertainty, the trend is clear. And it’s still pointing upward; the report projects child obesity rates will continue to climb through 2030, especially in Latin America, the Middle East, and East Asia.
How did we get here?
The shift aligns with the change in the kind of food environment today’s kids are raised in. Supermarkets, schools, and corner stores are stocked with foods high in calories, added sugar, saturated fat, and salt. Think sodas, packaged snacks, instant noodles — the kind of products that are designed to be cheap, convenient, and irresistible. That’s by design.
“Food companies are not social service or public health agencies; they are businesses with stockholders to please,” said Marion Nestle, a longtime scholar of food politics at New York University, over email. “Their job is to sell more of their products…regardless of the effects on health.” And unlike a generation ago, these foods are no longer confined to wealthy countries; they’re now widely available in LMICs, and are increasingly displacing traditional diets.
Ultra-processed foods — the buzzword taking health circles by storm — tend to encompass such foods. A rare randomized trial at the US National Institutes of Health found that people on ultra-processed diets ate about 500 extra calories per day than those on minimally processed ones. Most other studies show associations between ultra-processed food intake and obesity or poor health, though they can’t prove cause and effect.
But experts also debate about what counts as ultra-processed. The system used by the UN and many researchers to determine what qualifies as ultra-processed is too broad and sometimes lumps together very different foods. That’s why critics like Nicola Guess say the category “borders on useless,” pointing out that it can group together things as different as Oreos, tofu, and homemade soup made with a bouillon cube.
Still, the debate over definition doesn’t erase the broader finding: Diets heavy in these calorie-dense, heavily marketed products are consistently linked to worse health outcomes. “This is as close as you can get to a causal relationship [in public health],” said Rafael Pérez-Escamilla, a professor of public health nutrition at Yale University.
The other shift in the last 25 years is that kids today are far less active than even a generation ago. In global survey reports, more than 80 percent of adolescents fail to get the World Health Organization recommended hour of daily exercise — a sedentary shift that makes the impact of poor diets worse.
The result is a world where no region is untouched, but the picture looks very different depending on where you are. Richer countries like the US (21 percent), Chile (27 percent), and the UAE (21 percent) report strikingly high rates of childhood obesity. In some parts of the Pacific Islands, more than a third of children are obese, a trend linked to growing reliance on imported processed foods over traditional diets.
But this isn’t universal. In sub-Saharan Africa and South Asia, underweight is still more common.
That regional picture shows we’re in a patchwork of progress and crisis. Some regions are still battling too little food, others too much of the wrong kind, and many face both at once.
What can we do about it?
The drivers of this flip are structural — pricing, marketing, food availability — and that’s where the solutions are, too.
“Latin American countries are worried that obesity and its consequent chronic disease will bankrupt their health systems,” said Nestle. That concern has pushed governments to act faster than most. Chile’s 2016 warning label law and ad-ban package cut purchases of sugary drinks and snacks, and Mexico this year banned junk food in public schools, reshaping choices for 34 million children. “Impact studies show that they work to a considerable extent,” Nestle added. The UK’s soft drinks tax points in the same direction, pushing companies to reformulate beverages with less sugar.
By contrast, in the US, the Make America Healthy Again movement has delivered little beyond words. “The MAHA movement is all talk. … The policy document that came out a few days ago is essentially saying we’ll have no regulations or policies, we’ll only do research and voluntary guidelines,” said Barry Popkin, a longtime nutrition researcher at University of North Carolina. As Jess Craig reported previously for Vox, the Food and Drug Administration’s proposed front-of-package labels are a far cry from the bold stop-sign warnings in Latin America — the kind of measures experts say actually change behavior.
Of course, no single law is going to reverse the obesity curve, and nearly every country has struggled to get a handle on it. But measures like warning labels, soda taxes, and marketing restrictions at least sketch out what a serious policy toolkit could look like.
The decline in underweight is worth celebrating. But the rise of obesity, now surpassing it, reframes what malnutrition means in the 21st century. Calories alone are no longer the main problem; it’s the kind of calories children are consuming. We’re now in a world where we’ve partly solved one old crisis, only to stumble into another created by our food system.
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