Using nudges to improve food choices: An experiment in Uruguay

Ana Balsa, Cecilia Noboa and Patricia Triunfo run a nudge experiment in Uruguay to improve food choices:

In a recently published study (Balsa et al. 2023), we evaluate the impact of an intervention that involved sending WhatsApp messages to regular customers of a supermarket chain in Uruguay with the aim of nudging healthier food purchases.

We randomly assigned a subset of 1,590 regular customers to receive three short, simple messages per week for eight weeks (from July to September 2020). These messages focused on various topics: cooking at home, eating vegetables, fruits, healthy snacks, legumes and fish, and conscious and healthy eating. Their design aimed at addressing biases that are likely to lead to suboptimal food choices (see Figure 1).

For example, sending recurrent information via WhatsApp about the benefits of healthy foods helps address present bias. Proposing simple actions mitigates inaction due to inattention and decision fatigue, and highlighting public figures’ good habits makes the messages more salient and signals a social norm.

We found that, on average, customers responded favourably to the messages: they increased their purchases of fruits and vegetables by 8% and substituted sugar‐sweetened beverages for sugar‐free ones.

However, as with other behavioural economics experiments, reactions to nudges were qualitatively heterogeneous. Customers more likely to be uninformed or to suffer from cognitive inattention or present bias (those with lower education, lower income, or younger children) were more likely to respond directly to the nudges, increasing their purchases of foods and vegetables.

On the other hand, better-educated customers with higher incomes or no young children tended to substitute higher-calorie ultra-processed foods with lower-calorie ones. These customers even ended up increasing their total spending on this food, without affecting or even decreasing, in certain cases, the total number of calories or fats purchased.

These results indicate that interventions may need to discourage the consumption of ultra-processed foods in addition to promoting the purchase of healthy foods. The effects do not persist in the long term, suggesting that attention management, rather than information, is the primary channel driving the changes in behaviour.