Conference Coverage

Tweaking food delivery apps can lower calories purchased


AT ECO 2023

Changing the way food options and information is presented on food delivery apps, as well as default smaller portions, may encourage healthier selections, lowering the calorie intake by 4%-15%, show three new randomized trials from the United Kingdom.

The prominent positioning of low-calorie menu items, and restaurants with low-calorie main meals, on a food app emerged as the most promising approach to promote healthier eating, followed by preselecting smaller portions by default, and finally calorie labels, Anna Keleher, MPA, a behavioral scientist at Nesta, London, reported at the European Congress on Obesity (ECO) meeting.

“Many out-of-home meals have more calories than meals cooked in-home and using delivery apps is linked with a higher risk of becoming overweight or obese,” she remarked. “We’re interested in understanding more about delivery apps because they can be modified at scale easily and can reach millions of people with interventions to promote healthier and more nutritious options in these settings.”

Food delivery apps have surged in use in the United Kingdom with a 55% increase since 2015; examples include Uber Eats, Just Eat, and Deliveroo. “This trend is similar in the United States, with more and more consumers using delivery apps to buy food,” said Ms. Keleher, a senior adviser at the Behavioral Insights Team, New York.

Emma Boyland, PhD, an obesity psychologist from Liverpool (England) University, said: “Apps are an increasingly popular way for people to buy food and the virtual food environment is becoming as prominent as the physical food environment in how we go about obtaining meals.”

She highlighted the need to understand more about how food apps change the way we purchase and eat, but noted that “the work presented today” showed that “moving the position of food choices and information, as well as the brand name and imagery, influences what people end up buying and consuming.

“I think there’s a place for interventions that challenge these things and improve dietary health,” said Dr. Boyland, who chaired the session during which Ms. Keleher presented her results. “However, as we’ve seen with calorie labeling, they don’t always have the biggest effect on their own, so as is often the case, we need to take multiple actions, incorporating all the elements of the environment to make a meaningful difference.”

Three trials changing displays on simulated food delivery apps

“Delivery apps could reach millions of people and help us select healthier food options, and yet there is very little research looking at what works to promote healthier and more nutritious options in these settings,” Filippo Bianchi, MD, a colleague working with Ms. Keleher, said in a press release issued by ECO.

So the research team carried out a proof-of-concept testing of health-promoting interventions by developing a simulated food delivery app and asking 23,783 adults who typically use such services to choose a meal for themselves as if it were a real-life food delivery order.

“As a first step, we developed a simulated online food delivery platform to generate evidence on the effectiveness of our interventions,” Ms. Keleher explained, noting that the simulated platform included 21 restaurants and almost 600 food and drink items to choose from.

The research evaluated 14 interventions across three randomized controlled trials, displaying various food-ordering options that promoted lower-calorie options against a control. The trials investigated default choices (promoting the selection of small portion sizes through defaults, n = 6,000); positioning (promoting the selection of less calorie-dense options through positioning, n = 9,003); and labeling (promoting the selection of less calorific options through calorie labels, n = 8,780).

The primary outcome was the total number of calories in the basket at checkout. The results were adjusted for potentially confounding factors, such as body mass index, age, gender, and income.

For the trial that promoted smaller portions by default, “all of our interventions significantly reduced calorie purchases, with each additional intervention element increasing the effect sizes, which ranged from a 6% to 13% reduction in calories [–5.5% to –12.5% kcal/order; P < .05],” reported Ms. Keleher.

The second trial varied the position of both items on the menu and the order of restaurants – effectively, lower-calorie menu options were more prominent, and restaurant options with lower-calorie main meals were placed at the top of the restaurant selection page.

Ms. Keleher noted that there have been some concerns about whether this strategy would negatively affect restaurant business, so the research team counteracted this by also incorporating an option where low-calorie but high-price options were placed near the top of the display to promote healthier options but without loss of income for participating restaurants. This last intervention with low-calorie/high-price options placed near the top also led to reduced calorie intake.

“This showed that promoting low-calorie options does not necessarily mean damaging business revenue,” she said. “We hope that the industry can evolve to meet the widely recognized needs of society and consumers.”

Repositioning restaurants emerged as more effective than repositioning foods on the menu, while all interventions significantly reduced calorie purchases. “Effect sizes ranged from 6% to 15% reductions in calories purchased per order [P < .05],” reported Ms. Keleher.

The last trial tested seven calorie labels: four that changed the font size and location of the label, two that added a switch on/off filter for calorie label display, and one that was a calorie summary at checkout.

“All these standard calorie labels directionally reduced the number of excess calories with two [options] reaching statistical significance. Five out of seven labels significantly reduced calorie purchases with effect sizes ranging from 4.3% to –7.8% kcal/order (P < .05),” reported Ms. Keleher.

“This research is important for policymakers so they can understand the best way for companies to display calorie labels and what to include in regulations and guidelines,” she summarized.


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