Research flags online shopping features to unlock healthier food choices

In a randomized trial, simple digital features in an online grocery shopping platform significantly improved the nutritional quality of shoppers’ carts. The researchers tested a new toolkit with strategic and simple options, including color-coded nutritional quality signals and a healthier alternative prompt for healthier online grocery choices. 

The study by Duke-NUS Medical School, Singapore, included 328 participants shopping three times within three to six weeks on NUSmart, an online grocery store designed by the research team. One group shopped at a standard store, and the other group at a store with additional features for healthier choices. 

These digital features included signaling nutritional quality with a front-of-package traffic light — green (best), amber, and red — sorting groceries by nutritional value, showing real-time cart feedback, and suggesting healthier options. 

Shopping with these features led to healthier food choices across all three orders. 

Using these interventions, the average Nutri-Score of participants’ grocery carts improved from grades C to B. The features also helped to reduce purchases of calories (12.86 kcal), total fat (1.21 grams), saturated fat (0.85 grams), sugar (0.82 grams), and sodium (156.64 mg) per serving. 

“As online grocery shopping is rapidly gaining ground, we wanted to see if we could design low-cost, scalable online tools that could be used to nudge consumers toward healthier choices at the point of purchase. These results show the potential of these tools to improve diet and health outcomes,” says the study’s first author, assistant professor Soye Shin from Duke-NUS’ Health Services and Systems Research Programme. 

Nudging consumers

The researchers note that their study verified the effectiveness of front-of-package labels, which only marginally improved diet quality when used on their own, adding extra interventions. The results are published in the American Journal of Preventive Medicine. 

NUSMart showing labels and real-time feedback in Panel A, and healthier substitute offers in Panel B (Image credit: Duke-NUS Medical School).The front-of-package labels used in the study resembled traffic light signals to alert shoppers to foods’ nutritional quality. The researchers sorted items into green, amber, or red (with an “X” mark) based on their Nutri-Score points. 

This classification system assigns points according to products’ content of energy, sugar, sodium, saturated fat, fruit or vegetables, protein, and dietary fiber per 100g/mL. These points were converted into a five-letter grading system, from A (healthiest) to E (least healthy). 

The researchers sorted items by nutritional value using the Nutri-Score of foods, with the healthiest options appearing first. In the control online shop, items appeared in alphabetical order. 

In addition, shoppers could track the nutritional quality of their grocery carts with a pie chart, which indicated the share of items in each color band. They could also compare their carts with a reference basket for healthy grocery shopping curated by the researchers from past data. 

Participants could view up to four healthier alternatives for each selected food product with similar prices and characteristics. They could replace their option with this healthier version with the click of a button. 

Professor Patrick Tan, senior vice-dean for Research at Duke-NUS, comments: “This study reflects how smart, evidence-based interventions — when applied at the right moment — can empower people to make better everyday choices for their health. It also shows how research can lead to practical tools that improve individual choices and population health outcomes.”

Diet quality advantages

The authors say their findings underscore the advantages of introducing diet quality labels. Previous research also found online labels could increase healthy food consumption more than discounts. Moreover, US experts call for mandatory access to nutrition information in e-shopping, which is not always accessible to consumers online. 

Assistant professor Soye Shin (left) and professor Eric Finkelstein (right) (Image credit: Duke-NUS Medical School).“These results are encouraging, but the next step is to work with retailers to incorporate these features into existing online stores. Only then will the full value of this approach be realized,” says senior author and professor Eric Finkelstein, from Duke-NUS’ Health Services and Systems Research Programme. 

Meanwhile, as the US FDA updated its definition of “healthy” foods, researchers cautioned that consumers need support to understand what that means — what qualifies a food as healthy. The FDA has delayed its final rule for “healthy” food label requirements amid a US regulatory freeze. 

The researchers will expand their study to include consumers of low socio-economic status and limited nutritional knowledge to determine if the outcomes can be generalized. Their sample was relatively well-educated compared to the general population in Singapore. 

The team will also determine whether their multi-pronged intervention strategy can positively impact consumers’ health in the long term.