Study identifies best healthy eating nudges

Actions speak louder than words. Turns out that just telling people they need to eat healthy doesn’t work nearly as well as some simple physical actions. Clearly, with almost 70 per cent of us overweight, just talking about healthy eating isn’t enough.

Behavioral nudges have emerged as the best way to improve healthy eating, according to a new paper by Pierre Chandon, Professor of Marketing at INSEAD, and Romain Cadario, Assistant Professor of Marketing at IÉSEG School of Management.

Ever since Richard Thaler won the Nobel Prize in Economics, “nudge” has been front and center in the interest of researchers and policy makers. A simple definition of nudge is an intervention that attempts to influence behaviors without using economic incentives and while preserving freedom of choice.


In a meta-analysis of real-life experiments drawn from food science, nutrition, health economics, marketing and psychology, the authors find that behavioral nudges – facilitating action rather than providing knowledge or inducing feelings – can reduce daily energy intake by up to 209 kcal, the same number of calories as in 21 cubes of sugar.

“Just changing the amount of food on a plate or the location of the food – without necessarily educating people about nutrition content or convincing them that they should eat healthily – is the most effective intervention because you don’t need to rely on changing people’s beliefs or their goals,” said Chandon. “There is tremendous potential to help people to eat better.”

Seven ways restaurants and grocery stores can nudge food choices

In “Which Healthy Eating Nudges Work Best? A Meta-Analysis of Field Experiments” published in Marketing Science, Chandon and Cadario examined 299 results from 96 real-life field experiments. Their analysis was directly funded by INSEAD and IÉSEG.

The study identified seven different types of nudges and classified them into three broad categories, depending on how they worked: cognitive, affective and behavioral. Cognitive nudges provide information, such as nutrition counts or make healthy options more visible on the shelf or on the menu. Affective nudges seek to influence how people feel, without necessarily changing what they know, for example by touting the taste of the food, not its healthiness. Behavioral nudges try to directly change behaviors without necessarily changing what people think or what they want, for example by changing the amount of food on the plate or by making healthier foods easier to select and consume.

The above illustration shows the full list of nudges, with examples.

Which healthy eating nudges work best?

After the experiments were categorized, the professors collated the data and measured the effectiveness of each type of nudge using the standardized mean difference (also known as Cohen’s d). By standardizing the mean differences, we are able to compare the effectiveness of experiments using various units of measurements. To get a more intuitive grasp of nudge effectiveness, we computed the daily energy equivalent by multiplying the Cohen’s d value and the standard deviation in daily energy intake for an adult (537 kcal).

Considering all healthy food nudge experiments as a whole, the standardized mean difference or d is only 0.23, which is not very impactful. By separating the experiment results into cognitive, affective and behavioral groups, it is clear that some nudges are better than others.

Figure 1: The effectiveness of seven nudge types

Cognitive nudges provide information. Information on its own was not as successful a nudge as providing context to the information or as simply making healthier options more visible. The expected daily calorie reduction for cognitive nudges was about 64 kcal, or six sugar cubes worth of calories.

In comparison, affective nudges had an expected daily reduction of 129 kcal, around the same as 13 cubes of sugar. Behavioral nudges led to a more substantial change in calorie intake when compared to cognitive and affective nudges, the authors found. On average, they could reduce daily calorie intake by 209 kcal or 21 cubes of sugar.

Designing the best nudge

In addition to classifying and quantifying the effects of nudge experiments the researchers also compared other facets of the experiments – those in grocery stores vs. cafeterias; adults vs. children studied; experiments in the U.S. vs. those outside; nudges that promoted healthy choices vs. those that discouraged unhealthy choices; and food consumption vs. selection.

“The strength of our meta-analysis is not only to categorize interventions and measure their effectiveness. Our results are also robust when controlling for various population and study characteristics such as location, respondents’ age groups, study design or behavioral outcomes” Cadario said. It is important to control for these factors because they can be confounded with the type of nudge.

Cadario and Chandon found that the effect sizes for U.S. experiments were 47 per cent greater there than the ones conducted in other countries. This could be for several reasons: larger portions, a higher proportion of overweight Americans, or perhaps because they tend to focus less on the experience of eating and more on the health effects.

They also found that nudge experiments were most successful at reducing unhealthy eating rather than increasing healthy eating or reducing total eating.

Overall, the authors found that the best nudge experiment scenario for healthy eating outcomes was behaviorally oriented, focusing on unhealthy food consumption in an onsite cafeteria frequented by adults in the U.S which produced an effect size 4 ½ times larger than the typical scenario.

Marketing and healthy choices

Cognitive interventions have merit from an ethical point of view. Information is of value itself. However, providing information about calories or nutrition without a context did not have much of an impact on the subjects’ consumption.

“Change the shopping environment, the way information is displayed, the way products are displayed to influence customers to go in a particular direction. This is already happening, but the placement of healthy choices at the beginning or the end of the cafeteria line or the size of plates, glasses or portions can make an even bigger difference,” Chandon explained.

Business schools like INSEAD and IÉSEG are at the center of research on eating behavior, at the intersection of many academic disciplines and the business world. Business scholars are informed by medicine and public health researchers and go on to present results to food companies, retailers and others on the front lines of food service in order to help them transition to a healthier and more sustainable business.

“Marketing is not about selling more. Marketing is about creating value for the firm by creating value for the customers. By giving people not just large portions at a low price, but quality, food companies can help their customers eat better, which is an important goal for many of them” said Chandon.


Filed under behavioral nudges, healthy eating

4 responses to “Study identifies best healthy eating nudges

  1. Interesting but I didn’t take away a single action item. Tomorrow u see a nutritionist again. He’ll tell me to eat this and don’t eat that, which won’t take into account basic psychology, my specific individual health history, socioeconomic situation, genetics, exercise regime, sleep, stress, environmental pollution, detoxification, supplements, loss if insurance and job, and much more.

    I know this because I’ve heard the same tired spiel before. Not to mention he’s overweight so it isn’t working for him. Clearly if 70% if Americans are overweight, dietitians are losing the war. Some studies even show being overweight is an advantage to surviving hospitalizations and infections (I blogged about it).

    Weight is just one number. What about resting heart rate? HDL and HA1C? Those are great for me. Or the 405 miles I’ve biked in three weeks? Sure I’d like to be as thin as I was 30 years ago. But it seems unlikely. I need to keep trying to improve what I eat but also stop worrying about it. There is concern for health and there is fat shaming. And I don’t think we understand the extent to which our food choices are controlled by marketing, food science and what’s affordable.

    I’m all for nudges (long known as harm reduction in social services circles). But the rest, especially fad diets, don’t work. Well, that’s my comment.

    Liked by 1 person

    • Thanks for your comment. If 70% of Americans are overweight, it is they that are losing the war, not the dieticians. I am not a doctor or a dietician, I know that eating less crap and exercising more and getting enough sleep works for me. I am as thin as I was in high school. Maybe that is just luck. Everyone is different, but not that different. My resting heart rate is under 50 and cholesterol under 200. I pass along in the blog what I have found works for me and also stuff the sounds workable. After that, it’s up to you. Good luck!


  2. I think it’s great if you’ve never had weight issues. Be grateful for good genes, access to healthy food (I’m assuming) and lifelong good eating habits. I’ve been through several periods of food insecuriry, come to think of it. I think you’re wrong that “people.aren’t that different.”

    And I’m seeing a dietitian who says eat 1,800 calories a day. I sent him my latest ride if 33 miles showing I burned 1,410 calories just on that ride alone. It literally does not compute because it takes energy just for the body to run. He wouldn’t tailor the one day menu though he did give one 2,000 and one 2,200 calorie day pkan. but it has crap in it like flour-based products I have up. As mentuoned it did nothing for.l my weight. He has no knowledge of sports nutrition, a diet for thyroid issues, and isn’t allowed to give advice that doesn’t match the community clinic’s approved doctrine. It even has margarine, baked chips and juice on the list. Oh, he’s overweight, too.

    Clearly trained RDs are failing to help people with health issues with tailored diets. I fault doctors and med schools and insurance for not allowing alternative approaches. There are exceptions: My knee doctor said take tumeric, it’s as effective as NSAIDD, which I can’t take with making another thing worse. And he said get acupuncture, which I was but had to stop due to funds. Hopefully I start getting paychecks again soon.

    That’s all to say that I know you don’t write the articles you share but it’s worth questioning health information and in many cases it’s very hard to know what really works or doesn’t.

    Liked by 1 person

    • Thanks for sharing. Actually, if you read my About Me post, you can see that I have had weight issues much of my life. It wasn’t till I started writing this blog that the pounds just melted off. I don’t have any now, but I pay attention to what I eat and make sure that I get exercise every day. The statement “everything you eat becomes a part of you” was very helpful to me. Anyway, best of luck. It’s a one day at a time deal.

      Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s