What happened to obesity after Chile slew Tony the Tiger?

“In Sweeping War on Obesity, Chile slays Tony the Tiger.”

So read the headline of a front-page story in The New York Times in 2018 on a dramatic step Chile was taking to fight obesity. With some of the highest obesity levels in South America, the country had begun enforcing strict regulations on Frosted Flakes and other foods that exceeded set thresholds for sugar, calories, salt, or saturated fat in 2016.

Foods and beverages that exceeded the thresholds couldn’t be served in schools. They couldn’t be advertised on shows whose audience was more than 20% children. Their ads and packaging couldn’t feature cartoon characters or toys. Instead, the packaging had to feature one or more black stop signs displaying the word “ALTO” — which in Spanish means both stop and high — and specifying exactly what the contents were high in: sugar, calories, salt, or saturated fat. A public relations campaign encouraged children and parents to avoid packages with stop signs.

I hoped this approach would work. I’d spent much of the previous decade studying child obesity policies in the U.S., nearly all of which targeted schools: school meal requirements, school soda bans, physical education, nutrition education, and the like. None of these policies made a dent in child obesity, and I wasn’t sure they could. After all, my own research (with Doug Downey, Joe Workman, Brian Powell, and Nicholas Rowland) showed that kids gained weight faster during summer vacation, when school is out, than they did when school was in session.

Other research suggested that the obesity epidemic was caused by overconsumption of processed food, and until those foods were regulated it seemed like nothing much would change. In the U.S., limits on food advertising and packaging were non-starters because of free speech protections, consumer choice rhetoric, and lobbying by the processed food industry. Chile’s laws offered a glimpse into another world where food marketing could be regulated.

How big was the change, really?

I visited Chile in 2017, about a year after the reforms took effect. My collaborator, Francisca Bogolasky Flimán, returned to Chile in 2022, after completing her PhD at the University of Texas. Packaged foods do look different in Chile, but not as different as you might think.

Tony the Tiger has indeed disappeared from boxes of “Zucaritas” (Frosted Flakes), but the box now has orange stripes or claw marks that, like the Cheshire Cat’s smile, remind us of the animal that’s no longer there. Likewise the monkey has disappeared from boxes of “Mono Rolls” (Monkey Rolls), but the O in Mono (monkey) has an evocative tuft of hair on top, and is lighter toward the bottom, like the face of a monkey.

Both boxes have plain black stop signs, but the rest of the box is brightly colored and fun, with milk splashing into the bowl and flakes or chocolate falls bursting toward the grocery aisle. Sugary cereals can’t offer toys any more, but they sometimes advertise a cash lottery, which might appeal to children, parents, and anyone else rolling their cart down the aisle.

Some other cereals kept their mascots by switching from sugar to stevia, a noncaloric sweetener, which lets them avoid being labeled as high in sugar or calories.

Although stop signs appear on packaged goods in grocery stores, they are not required at restaurants and food service establishments — a loophole that public health advocates in Chile have been trying to close. Ice cream parlors still serve richly colored, creamy, sugary treats without any warning. Enormous meat sandwiches remain a popular lunch at neighborhood diners. McDonald’s Happy Meals do not display any stop signs, though they can only use cartoon characters if they reduce calories and fat below prescribed limits. The Happy Meal I bought in the Santiago Airport had fewer French fries than I remembered from back in the U.S., presumably to stay below limits.

Did it work?

Several studies have appeared since Chile’s reforms started, and, for the most part, the news seemed good. A study of Walmart grocery purchases showed that consumers had switched away from products with stop signs, especially if they had previously thought those products were healthy. Other studies confirmed declines in the energy, sugar, sodium, and saturated fat density of foods and beverages served in schools and advertised on television.

But none of the studies asked the most basic question: Did child obesity decline?

The answer was hiding in plain sight. Every year, Chile’s physical education and homeroom teachers measure the height and weight of children in pre-K, kindergarten, first grade, and ninth grade. Those measures are used to calculate body mass index (BMI) and then to calculate the percentage of children who exceed the World Health Organization’s BMI thresholds for obesity and overweight. Using those data, Bogolasky Flimán and I graphed trends from three years before Chile’s reform (2013) to three years after (2019). Our findings were published earlier this year in the Pan American Journal of Public Health.

Results for the first year of Chile’s reforms were encouraging — at least for young children. Between 2016, when Chile’s reforms started, and 2017, the prevalence of overweight or obesity dropped by 1 to 3 percentage points in pre-K, kindergarten, and first grade.

But the rates rebounded the next year. By 2018, child obesity was back to where it had been before the reforms. And 2019 looked about the same as 2018.

This rebound may sound familiar. Anyone who has ever tried dieting knows that weight is hard to keep off. Clinical research confirms that weight loss is greatest in the first six to 12 months of a diet; after that, at least half of the weight typically comes back. Almost every weight loss study sees a rebound if dieters are followed for more than a year.

But we had never seen it happen to a whole country before.

Unlike young children, ninth graders didn’t even see a one-year drop. Even in the first year after the reform, ninth graders’ weight kept climbing as though nothing had happened. By 2019, overweight and obesity among ninth graders were 2 percentage points higher than they had been when the reforms started in 2016.

The ninth-grade results shocked us, though if you’ve lived with (or been) a teenager, you know they can be a little contrary. A review of research on efforts to change students’ eating habits found modest changes in young children, but no effect at all on adolescents.

Just wait?

The finding that Chile’s reforms haven’t made a lasting dent in obesity has met some resistance.

One argument made by apologists for Chile’s reforms is that they simply haven’t had long enough to work. A recent report on Chile’s food policies asserted, “Experts say that it can take decades for obesity rates to budge.”

I find it hard to see why any expert would say that. There are no examples of anti-obesity interventions that took decades to work. While it might take a while to see declines in diabetes or heart disease, the effects of diet on weight, if they occur, are typically clear within six to 12 months. This is, in fact, what happened in Chile. The common problem is that the lost weight returns. This is what happened in Chile, too.

If Chile’s 2016 reforms do take decades to work, it will be impossible to tell. In early 2020, the Covid-19 pandemic hit Chile, closing schools and raising obesity to new levels. In mid-2021, the U.S. Food and Drug Administration approved weekly semaglutide for obesity after clinical trials showed that it could reduce body weight by 15% on average. If this generation of Chilean children grows up to be heavier or lighter than previous generations, there will be no way to isolate the effect of the 2016 reforms from everything else that happens in the meantime.

To put the argument in personal terms, imagine you were overweight and changed your diet for three years. And suppose that the scale showed exactly the same value three years later. What would you think of someone saying that you just hadn’t given the diet enough time? Claiming that more time is needed is just a way to avoid reckoning with what’s already happened.

Compared to what?

Another popular argument is that it’s difficult, if not impossible, to know how effective Chile’s reforms were because there was no good comparison group. There’s no comparable data from a neighboring country, such as Argentina, and it may be that Chile’s children would have gained weight faster if the reforms hadn’t passed.

It’s a valid concern, but the data show that Chile’s obesity rates weren’t rising in the years before the reform. Why imagine that they would have risen in the years after?

And from a policy point of view, how much does it matter? The purpose of Chile’s reforms was to drive obesity down — not just relative to what might have happened otherwise, but absolutely. If obesity didn’t go down, or didn’t stay down, the key question is not whether things might have been worse. The key question, for policy, is what to try next.

What’s next?

Although Chile’s reforms look radical to Americans, they didn’t fundamentally change Chile’s food system. Some cereals switched from sugar to stevia, and some consumers switched from cereals with stop signs to cereals without. But all the changes took place within a system emphasizing packaged, processed foods.

It certainly wasn’t a reform that the processed food industry wanted. But it was a reform they could live with.

And it clearly wasn’t enough. To reverse the obesity epidemic, policies may be needed that push consumers away from packaged foods and toward whole foods — not from one type of cookie to another, but from cookies to Chile’s famous apples, pears, and citrus fruits.

Warning labels were just a first step in fighting diseases caused by tobacco, and labels made only a small, fleeting difference in Chile’s fight against obesity as a disease caused by processed foods. As Fernanda Mediano at the Pontifical University of Chile has suggested, future regulations would need to address internet marketing and might discourage consumption of artificial sweeteners as well as sugar.

If Chile were to follow the tobacco playbook further, eventually it would add exorbitant taxes to foods like chips, soda, candy bars, and cookies. Vending machines would not be allowed to sell those foods — they might even be put in locked cases.

Reforms like those might seem sensible from a public health perspective, but they would be challenging to implement politically. The processed food industry would resist, and some consumers might resent them. The fight over regulating tobacco has been going on for 60 years, and regulating food is much trickier. While all tobacco is bad for health, it’s much harder to draw a clear line between healthy and unhealthy foods.

Will Chile — or any other country — have the nerve to go further?

Paul von Hippel is a professor and associate dean for research at the LBJ School of Public Affairs, University of Texas, Austin.