Nutri-Score labelling in the out-of-home food sector: evidence on effectiveness from a large, randomised control trial in UK restaurant settings
This large-scale randomized control trial in UK restaurants demonstrates that adding Nutri-Score labels to menus, alongside calorie information, significantly improves both the perceived effectiveness of menu labeling and the nutritional quality of food orders compared to calorie labeling alone.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer
Imagine walking into a restaurant where the menu is a maze. You're hungry, the options look delicious, but your brain is tired. You want to eat something that makes you feel good, but figuring out which dish is the "healthiest" feels like trying to solve a math problem while balancing on a unicycle. This is the daily reality for millions of people who eat out, and it's a big part of why many of us struggle with our weight and health. Scientists have been trying to fix this menu maze for years. One popular tool is the "calorie count," a simple number telling you how much energy a meal has. But numbers can be boring and confusing; knowing a burger has 600 calories doesn't always tell you if it's a "good" or "bad" choice compared to a salad. Enter the Nutri-Score, a colorful traffic-light style label that rates food from A (green, super healthy) to E (red, least healthy). It's like a quick, easy-to-read grade on a report card for your food. The big question researchers have been asking is: If we put these colorful grades on restaurant menus alongside the boring calorie numbers, will it actually change what people order, or will people just ignore it?
This study decided to find out by turning a real-life restaurant in Liverpool, UK, into a giant science experiment. The researchers set up a "choose your own adventure" scenario for 672 volunteers. They split the days of the week into two different worlds. On some days, the menus showed only the standard calorie counts (the control group). On other days, the menus showed the calories plus the colorful Nutri-Score grades (the intervention group). The participants didn't know which "world" they were in; they just thought they were having lunch. The researchers then watched closely to see what happened.
The results were pretty exciting. When the colorful Nutri-Score labels were on the menu, people didn't just think the information was more helpful—they actually acted on it. The study found that the meals people ordered on the "Nutri-Score days" were significantly healthier than the meals ordered on the "calorie-only days." It wasn't that everyone suddenly ordered a giant salad and skipped dessert; rather, the overall quality of the food went up. The researchers measured this using a special scoring system where a lower number means a healthier meal. The Nutri-Score group had scores that were about 0.89 points lower, which is a meaningful shift in the world of nutrition.
However, the story has a few twists. While the overall quality of the food got better, the study didn't find a massive spike in people ordering only the "A" or "B" graded items, nor did it see a huge drop in people ordering the "D" or "E" items. It seems the labels didn't force people to pick the absolute healthiest or avoid the absolute unhealthiest in a dramatic way. Instead, the labels seemed to nudge people to make small, better choices across the board—maybe swapping a sugary soda for water, or picking a slightly less fatty sandwich. The study also checked if people tried to "cheat" later in the day by eating less after their restaurant visit, but found no evidence of that; the healthier choice seemed to stick just for that meal.
Interestingly, the study also looked at who was affected. In some other countries, researchers found that these labels worked better for people with higher education levels. But in this UK study, the labels worked for everyone, regardless of their education or background. The participants also said they liked the idea of having these labels on menus, with about 69% saying they would support a government rule making them mandatory.
So, what's the takeaway? The paper suggests that adding these colorful, easy-to-read grades to restaurant menus is a promising tool. It's not a magic wand that will instantly cure obesity, but it appears to be a helpful nudge that makes the "healthy choice" the "easy choice." By making the nutritional quality of food obvious at a glance, we might be able to guide people toward better meals without them even realizing they're being guided. It's a small change on a piece of paper that could lead to a healthier future for the whole country.
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