DAVIS, CALIF.  — Consumers, when they noticed warning labels for menu items with high levels of added sugar, significantly reduced their grams of sugar ordered in a study led by researchers at the University of California — Davis and published April 17 in the American Journal of Preventive Medicine. However, since only 21% recalled seeing the warning labels, the reduction was not significant when accounting for all participants.

In the study 15,496 US adults viewed fast-food and full-service restaurant menus either displaying no warning labels (the control group) or icon-only warning labels for added sugar next to items that contained over 50% of the daily recommended limit for added sugar. The researchers collected data in May and June of 2021.

Warning labels reduced the relative probability of ordering the items with high levels of added sugar by 2.2% and led to a reduction of 1.5 grams of added sugar ordered, which was not statistically significant. Among the 21% who noticed the warning label, the result for grams of sugar ordered was significant as they ordered 4.9 fewer grams than the control group.

Of the calories consumed in the United States, 21% come from eating at restaurants, according to the study.

“Given the frequency of restaurant food consumption, these modest effects could lead to meaningful changes in sugar intake at the population level, and the labels should motivate restaurants to reduce the added-sugar content of their menus,” said Jennifer Falbe, Sc. D., a researcher in the Department of Human Ecology and lead author.

The study also involved researchers from the Harvard T.H. Chan School of Public Health, the University of Pennsylvania, the Center for Science in the Public Interest and the University of North Carolina. Bloomberg Philanthropies provided funding.

The United States mandates the labeling of added sugars on packaged foods and the labeling of calories on chain-restaurant menus. Chain restaurants are not required to disclose the amount of added sugar in menu items.