Food delivery apps can lower salt use with one small change

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Mar 30 2025

Could a simple menu tweak lower China’s salt intake? This real-world study on food delivery apps shows how a default option can quietly drive healthier choices nationwide.

Study: Can behavioural nudges promote reduced-salt dish orders on meal delivery apps? Image Credit: Naypong Studio / Shutterstock

In a recent study published in the journal Public Health, researchers investigated whether default menu options and educational health messaging on a Chinese meal delivery application (MDA) could encourage consumers to order reduced-salt dishes in restaurants.

Their findings indicate that educational health messaging alone did not lead to consumers making healthier choices. However, the presence of a ‘salt submenu’ that required them to explicitly choose between a regular salt or reduced salt option increased their likelihood of selecting reduced-salt options. The most effective intervention involved a salt submenu with the default set to ‘reduced salt’.

The educational message did not significantly enhance the effectiveness of submenu interventions, suggesting that informational nudges alone or in combination may be insufficient without structural changes.

Background

Research suggests that modifying food environments through behavioral nudges can encourage healthier eating habits. Traditional methods, primarily health education campaigns, have been widely used; however, recent studies indicate that ‘decision structure’ or ‘architecture’ nudges, which frame or organize choices in a way that encourages a beneficial outcome, are more effective.

Researchers have tested nudging strategies such as menu design modifications to promote healthier choices by reducing sodium, sugar, fat, and energy intake. However, most studies are conducted in controlled settings, such as workplace cafeterias or virtual experiments, which limits their real-world applicability.

Excessive salt intake is a major public health concern that increases the risk of hypertension. Notably, an estimated 27.5% of Chinese adults have hypertension, with only 11% managing the condition adequately.

Despite strong evidence that lowering salt intake reduces blood pressure, Chinese adults consume an average of 9.3g of salt per day, nearly double the recommended 5g by the World Health Organization.

With rising urbanization, MDAs are increasingly popular, but these platforms rarely come with dietary guidance. As their role in food environments expands, researchers are exploring their potential to help people make healthier choices when ordering in.

About the study

Researchers aimed to assess the impact of two types of nudges—educational health messages and menu default options—on a commercial MDA in China. By conducting a real-world intervention trial, researchers compared the impact of these strategies on consumer choices.

They employed a factorial design, testing two factors: educational information (present or absent) and submenu type (no submenu, a submenu defaulting to “regular salt,” or a submenu defaulting to “reduced salt”).

Five intervention groups and one control group were established. Restaurants in intervention groups adjusted their menus accordingly, while those in the control group maintained their standard settings.

Between February and May 2021, 903 restaurants were recruited across various cities in China through open invitations and targeted outreach. The research team randomly assigned each restaurant to one of six groups, each with about 405–406 participants.

They selected one to three popular menu items for submenu modifications. Some restaurants failed to implement interventions correctly, and only 131 were fully compliant throughout the study. During the intervention period between July and August 2021, meal orders were tracked. Reduced-salt orders were identified through submenu selections or customer comments.

Since dish-level data were unavailable, the number of reduced-salt orders was estimated by dividing the number of reduced-salt dishes by four, the average number of items per order.

Data from 870,942 meal orders were analyzed using multiple linear regression models that compared the effectiveness of the interventions while adjusting for characteristics such as cuisine type and restaurant location.

Findings

The educational message alone had no significant impact on salt reduction. However, the salt submenu, which explicitly provided ‘regular salt’ and ‘reduced salt’ options, significantly increased orders of reduced salt. In unadjusted models, the presence of a salt submenu increased reduced-salt orders (coefficient: 9.3; P < 0.1), and the effect remained significant, though attenuated, after adjusting for restaurant location and cuisine type (coefficient: 2.9; P < 0.1). These coefficients reflect approximate percentage-point changes in the likelihood of reduced-salt orders per intervention group.

The salt submenu with a ‘reduced salt’ default was the most effective intervention, generating the largest increase in reduced-salt orders across all groups. Specifically, this intervention (Group B) achieved the highest adjusted effect (coefficient: 49.5; P < 0.01).

The combined intervention of the educational health message and the salt submenu with the default setting of ‘reduced salt’ also had some effect on promoting reduced-salt orders, but this effect was not statistically significant. The authors noted that this lack of significance may be attributable to the very small sample size in this group (only six restaurants), which limited statistical power rather than indicating ineffectiveness of the intervention.

Findings suggest that modifying choice architecture through decision structure nudges, such as submenus and default settings, is more effective than traditional health education.

This estimate is based on applying the observed 1.4% reduced-salt ordering rate across China’s daily average of 55.7 million takeaway orders. This 1.4% rate was derived from the actual proportion of reduced-salt orders observed across intervention groups during the study period. If implemented nationwide, such an intervention could result in over 160 million additional reduced-salt orders per year, significantly decreasing sodium intake and helping to prevent hypertension.

Conclusions

These results highlight the potential for integrating behavioral nudges into food delivery platforms to improve public health, marking the first study to explore salt-reduction interventions on meal delivery apps (MDAs) in China. They demonstrate that choice architecture approaches, such as salt submenus and default settings, can be effective in encouraging healthier choices.

While educational health messages are widely disseminated, their impact may be limited due to the effort required to implement them. Even when combined with the salt submenu intervention, the educational message did not enhance the salt reduction effect.

The study also highlighted ethical concerns, as some restaurants hesitated to implement a reduced-salt default, fearing misalignment with consumer preferences. Although the reduced-salt default was most effective, fewer restaurants implemented it, reflecting a tension between efficacy and perceived consumer acceptability.

Limitations include differing dropout rates among groups, a small sample size in one intervention group, and the inability to analyze data at the dish level. This could potentially undervalue the effect significance of the salt submenu intervention. Future research should explore broader implementation across diverse restaurant settings, assess long-term changes in consumer behavior, and address potential resistance from restaurants to optimize the effectiveness of the intervention.