Example of a color-coded Nutri-Score food labelShare on Pinterest
Do color-coded food labels, such as this Nutri-Score label, influence food choices? Jörg Carstensen/picture alliance via Getty Images
  • A diet that is high in salt, sugar, and saturated fat and low in whole grains is a leading risk factor for noncommunicable diseases.
  • A recent systematic review suggests that color-coded nutrition food labels and warnings on food packaging correlate with healthier food choices.
  • The researchers, from Australia, Canada, New Zealand, the United Kingdom, and the United States, believe that their study supports mandatory front-of-package labeling policies.

Diets high in nonnutritious foods increase the risk of noncommunicable diseases, which account for 71% of deaths worldwide.

Color-coded labels and warning labels are in common use on the front of food packages globally. They aim to encourage people to eat more healthily to reduce the burden of diet-related illnesses and deaths.

Before this study, it was not clear whether these labels effectively influence consumer purchases.

Jing Song, Mhairi Brown, and colleagues from the Queen Mary University of London in the United Kingdom explored the evidence with researchers from the University of New South Wales in Australia, the University of Calgary in Canada, the University of Auckland in New Zealand, and Resolve to Save Lives in the United States.

Their findings appear in PLOS Medicine.

To quantify the effects of front-of-package labeling, the authors reviewed data from 134 peer-reviewed studies published between January 1990 and May 2021.

They used the network meta-analysis method to summarize the results from these studies.

This approach helped the team evaluate the effects of the traffic light labeling system (TLS) and the Nutri-Score (NS) color-coding labeling system. The researchers also examined the impact of the nutrient warning (NW) and health warning (HW) labeling systems.

The authors state:

“The primary outcomes of our systematic review were measures regarding the changes in consumers’ purchasing and consuming behavior, which contain the probability of choosing less healthful or more healthful products, self-reported ratings of purchase intention, overall healthfulness of products purchased, and energy and nutrient […] content of products purchased/consumed.”

The study’s authors report: “We found that the TLS, NW, and HW were associated with an increased probability of selecting more healthful products.”

NS and warning labels seemed to help reduce consumers’ likelihood of buying “less healthful products.”

Song and fellow researchers believe that TLS, NW, and HW labels affected purchasing behavior by clarifying the nutrition information. In this way, they promoted “positive attitudes toward healthful foods” and negative attitudes toward less nutritious products.

Color-coded labels had a more significant effect in terms of influencing shoppers to buy healthy foods. Conversely, warning labels appeared to provide a stronger deterrent against opting for unhealthy purchases.

According to the authors, their study supports “mandatory front-of-pack labeling policies in directing consumers’ choice and encouraging the food industry to reformulate their products.”

Song and colleagues mention several limitations to their study. For instance, they acknowledge the differences in the type, format, and position of labels, as well as the variations in study populations and experimental settings across the reviewed studies.

Most of the research papers that they evaluated were laboratory studies, so real-world data on food consumption were limited. The team also admitted to a “lack of long-term impact assessments.”

Medical News Today asked Dr. Mir Ali, M.D., a bariatric surgeon and the medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, whether food labels really influence purchasing behaviors.

The surgeon agreed with the study findings that color coding and warnings make a difference:

“I think that if people are more aware of the health benefits or detriments of a certain food or product, then [labels] may steer them more toward a healthy product.”

However, Dr. Ali felt that the current labeling system in the U.S. “is not forthcoming” in providing clear, accurate nutritional information.

For instance, some food manufacturers list chemical names for sugars, which could lead some people to believe that a product is sugar-free.

Dr. Ali added:

“I think people have this impression that if something is labeled ‘healthy,’ it’s got to be healthy or organic or free range […] — some of the buzzwords. So, they often just look at that and say, ‘OK, I’m eating healthy.’ They don’t look at the calorie content or the actual makeup of what they’re eating, whether it has a lot of fat or cholesterol, or other things that may not be in their best interest.”

As a bariatric surgeon and weight loss specialist, Dr. Ali counsels his patients on eating properly after surgery.

He suggests that labels should include recommended consumption limits: “[Labels could say] this food falls into this category, and you should have only this amount or limit this amount per day. Or, this food is in the ‘Green Zone’ where you don’t have to limit how much you eat [of] this in a day.”

However, Dr. Ali acknowledges that people mainly buy what they want, healthy or not.

Further, he shares: “There’s a lot of controversy [about] what is a proper diet […]. There’s a lot of different opinions, especially for children.”

Noel Anderson, Ph.D., is the former president of the Institute of Food Technologists, a scientific community for food professionals.

In a podcast with FoodNavigator-USA, he comments that many shoppers lack clarity on what healthy eating is:

“I don’t think there’s a deep understanding about what healthy eating really means to the common consumer. Research has clearly shown that consumers are more aware and claim that they want to eat healthy, but for too many of them, eating healthy simply means fresh, but has no bad stuff in it. That’s a pretty narrow definition.”

Dr. Anderson continued: “Furthermore, when you look at their behaviors, […] deliciousness drives purchases […].”

Dr. Ali believes that making clearer labels is “a good step in the right direction.” Ultimately, though, individuals should take responsibility for educating themselves and choosing foods for health’s sake.