Comprehensive food regulations lower obesity risk among children

Chile's complementary set of policies targeting food products high in fat, salt and sugar plausibly reduces the risk of school age children being overweight or having obesity, finds a study published in The Lancet.

Chile ranks among the highest countries globally for rates of childhood overweight and obesity. To combat this issue, in 2016 Chile implemented one of the world's most comprehensive and ambitious food policies, the Food Labelling and Advertising Law (FLAL).

The FLAL targets foods and drinks high in sugars, saturated fats, salt, or calories through three core measures: mandatory front-of-package warning labels in the form of black octagons, restrictions on the sale of such products in schools, and limits on food marketing directed at children.

Although individual national measures like sugar taxes on soft drinks have been associated with improved health outcomes, this is the first study to plausibly demonstrate that a package of policies can reduce early childhood overweight/obesity risk at the national level.

These results offer strong evidence for policymakers around the world. They support mandatory front-of-pack nutrition warning labels, restrictions on unhealthy food in schools, and marketing bans as effective, practical ways to tackle the childhood obesity epidemic."

Prof. Guillermo Paraje, Professor of Economics, Universidad Adolfo Ibáñez Business School, Chile

National data on more than 300,000 schoolchildren aged four to six in Chile was used to compare children's weight from the years before the introduction of FLAL with the weight and size of children in the same school grades after the first phase of the law came into place in 2016.

The study found that children who had been at school for 18 months after the introduction of FLAL Phase 1 were less likely to be overweight or have obesity than those in the same grades before FLAL. Girls had a 2.9% lower risk of overweight or obesity (a reduction of 1.4 percentage points from a pre-FLAL rate of 47.7%) while boys had a 2.4% lower risk (a reduction of 1.2 percentage points from a pre-FLAL rate of 52%.)

The study also found a plausible causal impact in the cohort of schoolchildren aged four to six after only six months of the FLAL Phase 1; girls had a 1.9% lower risk of overweight or obesity (a reduction of 0.9 percentage points from a pre-FLAL prevalence of 47.4%) and boys a 2.2% lower risk (a reduction of 1.2 percentage points from a pre-FLAL prevalence of 52%).

Phases 2 and 3 of FLAL set stricter limits on sugars, saturated fats, salt, or calories. These phases were introduced in 2018 and 2019, so they did not impact the study's results.

Dr Nieves Valdes, Associate Professor of Economics, Universidad Adolfo Ibáñez Business School (Chile), says, "Although the reduction in obesity and overweight risk among young school children may seem modest, it is likely that the further tightening of the law in later years will have increased the impact, especially given evidence that there was a greater drop in sales of labelled food products during Phase 2 of the FLAL compared to Phase 1."

"Additionally, even a small weight reduction for children who have overweight or obesity is likely to bring meaningful long-term health benefits, given the strong links between childhood obesity and later risk of obesity, diabetes, hypertension, and cardiovascular disease, as well as evidence that early prevention can substantially lower these risks."

The researchers note some limitations of their studies, including that the plausible causality of the relationship relies on the assumption that, if the FLAL hadn't been introduced, the two cohorts of school children would have followed the same nutrition trends, which cannot be tested although support for the assumption was provided through pre-policy trends. Additionally, the children's weight was collected by school staff who, although trained for this task, may not achieve the same precision typically found in primary health care settings.

Writing in a linked Comment, Professor Simone Pettigrew and Dr Daisy Coyle, The George Institute for Global Health (Australia), who were not involved in the study, say, "In a policy environment where industry opposition constitutes a formidable obstacle to the implementation of health-promoting policies, high-quality, real-world evidence is critical. […] the research results strengthen the case for governments to move beyond incremental, single-policy approaches and to instead implement comprehensive, integrated strategies to improve food environments. In particular, the results highlight the potential for policy suites including mandatory warning labels and marketing restrictions on unhealthy foods and school food minimum standards to produce meaningful outcomes."