Some of the world’s most extensive regulations on the marketing and availability of sugary and fatty foods to children did not reduce obesity among elementary and high school students in Chile, according to researchers at The University of Texas at Austin. The research, published in the Pan-American Journal of Public Health, sheds light on how food policies can affect weight.
In 2016, Chile began to regulate the marketing and availability of foods high in calories, total sugars, sodium, or saturated fat. Chile’s reforms gained international attention, including a 2018 New York Times story reporting that Chile had “killed Tony the Tiger,” removing the famous mascot from boxes of Sugar Frosted Flakes. Research verified dramatic changes in foods advertised on TV, sold at grocery stores, and served at schools in Chile. But until now no research had asked whether child obesity declined as the law intended.
Researchers analyzed obesity and overweight prevalence among elementary and high school students in Chile, before and after the country’s 2016 regulations. Using body mass index thresholds defined by the World Health Organization, researchers found that one year after Chile’s food reforms, overweight and obesity fell by one to three percentage points among students in Pre-K, kindergarten and first grade. However, those rates rebounded to pre-reform levels the next year in 2018.
“Many dieters are familiar with the frustration of losing weight only to have it come back within six to twelve months," said Paul von Hippel, a professor in the LBJ School of Public Affairs at UT who conducted the research with Francisca Bogolasky Flimán at the University of Chile . "What's shocking here is to see that happen to a whole country’s children. Either children’s metabolisms slowed to match their new diets, or children and parents figured out a way to eat as many calories as before, despite changes in food content and advertising.”
Results for teens were worse than those for young children. Among ninth graders, overweight and obesity prevalence rose by over two percent in the three years after the reforms.
Since the 1980s, the prevalence of overweight and obesity have increased in many countries, including in the United States and Latin American countries such as Chile. Most evidence suggests that the major cause of the global obesity epidemic is not reductions in physical activity, but increases in consumption, especially of processed foods and beverages that are low in fiber and high in energy from fat and sugar.
Chile’s regulations, enforced in 2016, aimed to reduce the consumption of unhealthy processed foods and beverages, especially among children under 14. These regulations included restrictions on advertising, packaging, availability and the introduction of warning labels. Certain foods and beverages cannot be advertised on television or radio shows whose audience is more than 20 percent children, cannot be packaged or advertised with toys or cartoon characters, and must carry labels, shaped like stop signs, that feature the Spanish word alto—which means both stop and high—warning that contents are high in calories, sugars, sodium, or saturated fat. Schools cannot serve stop-sign foods and must provide nutrition education.
Chile’s reforms have served as a model for other countries, including Peru, Uruguay, Argentina, Mexico, and Israel. But this research suggests that the desired reductions in overweight and obesity have yet to materialize.
Data came from the Survey of Nutrition, a mandatory survey in Chile, conducted by physical education and homeroom teachers who measure the height and weight of school children. Researchers used data from three years before Chile’s food regulations (2013) to three years after (2019). Over this seven-year period, the Survey of Nutrition included data from 85 percent of children in participating schools and grades – an annual average of 185,169 children per grade in 9,006 schools. Researchers acknowledge limitations such as the absence of a comparison group of children who were not subject to Chile’s food regulations and the inability to follow up after 2019 due to the impact of COVID-19 on the trajectory of obesity.