Impulsive snacking at the checkout counter: nudging consumers towards healthier 'grab-and-go'-snacks

Candy aisle near checkout 

Tempting snacks placed right near the checkout counter can be hard to resist. Even though you know buying one is not in your best interest, they catch attention. These high-profit 'grap-and-go' snacks are particularly hard to ignore at the end of a shopping trip after making dozens of decisions. Even at my local shoe store, they tried to tempt me in buying candy (see picture).

In our recent paper published in BMC Public Health, we (that is Hans van Trijp, Kai Otten and myself) report two nudging studies on whether assortment structure and accessibility of healthier snacks influences consumer choices. The idea was that providing a larger assortment of healthier snacks and putting them on top of shelves makes these snacks more salient, attractive and convenient, leading hopefully to higher sales.

To test this idea, we first carried out a study among students in which we asked them to make a hypothetical choice from a shelf displayed at their computer screen. The results of this study showed that when the majority of snacks is healthy, students were are more likely to choose such a snack. Although this may seem obvious, they were equally satisfied with their choice and did not feel restricted.

However, lab studies do not always provide reliable predictions about how people behave in real-life. Therefore, we conducted a  field experiment in hospital 'De Gelderse Vallei'. We now put an actual snack shelf near the checkout of the staff canteen. Each week, an alternative snack assortment was on display. The assortment included either 25% or 75% healthy snacks. We also altered their place on the shelf (either on the higher shelves or the lower shelves). On completion of the study, we also conducted a brief survey among employees.

When 75% of the assortment consisted of healthy snacks, sales of healthy snacks were higher. In contrast to our expectations, putting healthy snacks at the most convenient (top) shelf space did not impact consumer choices and sales. It could be that our manipulation was not strong enough (see picture). Interestingly, the majority of surveyed employees did not notice assortment changes. When asked, however, they preferred the shelf displays including the larger variety of healthy snacks.

Overall, these studies show the size of a healthy assortment of snacks matters. A relative large assortment of healthy snacks is able to influence consumer choices. However, we do not know whether this intervention really leads to better snacking habits at the longer term. Moreover, these types of interventions are typically more successful in canteens than those in restaurants and grocery stores, where financial interests are at stake.  


While not all nudges are effective (see for example our nudging study among children), this nudge might be worth to give a try. Without forbidding any foods, a larger assortment of healthy snacks may catch consumer attention and even seduce them to purchase. 


Nudging paper in BMC Public Health: Healthy snacking at the checkout counter: a lab and field study 


van Kleef E, Otten K, & van Trijp HC (2012). Healthy snacks at the checkout counter: A lab and field study on the impact of shelf arrangement and assortment structure on consumer choices. BMC public health, 12 (1) PMID: 23231863

Watch 3-year-old Lukas grazing snacks all day: A confronting Dutch childhood obesity awareness campaign

'Also happy with this environment?' is the question posed by the Dutch Nutrition Center in their new campaign. The video of this campaign is definitely worth watching.

Many children have poor eating habits which may lead to overweight and obesity. Children are constantly bombarded with unhealthy, high-caloric snacks and meals. As a result, children nowadays live in a so-called 'toxic food environment', a term invented by obesity researcher Kelly Brownell. 

Successful obesity awareness campaigns require careful consideration of the target group and a key relevant message. On the one hand, they need to make parents aware of the seriousness of the problem. On the other hand, they need to provide useful information and not stigmatize or shame overweight children. This is not simple, as shown by a failed and controversial US childhood obesity campaign.

I particularly like the final scene of the video in which Lukas refuses the healthy meal cooked by his parents. It is a very familiar scene for many parents, including myself. Have a look yourself!

Just a bite or the full portion size? Dramatically smaller snack portion sizes satisfy hunger and cravings

A key reason we are getting overweight is because we eat too large portion sizes of food. But is this overeating giving us more satisfaction? Could eating smaller portions be similarly effective in decreasing food cravings or feelings of hunger as larger portions? That was the key question in the study that I conducted with Mitsuru Shimizu and Brian Wansink while visiting the Food and Brand lab. The paper is now published in Food Quality and Preference (see also full-text paper).



We presented 104 participants with either a small portion of three commonly craved snacks - chocolate, potato chips and apple pie - or substantial larger portions of the same snacks. For example, the small portion of chocolate was 10 grams, while the large portion was 100 grams. Feelings of hunger and craving were assessed just before participants started with the taste test, immediately after the taste test and about 15 minutes later. Secretly, we also measured how much participants ate.

Results show that although providing larger food portions increased snack calorie intake by 77% (103 calories), after 15 minutes, they do not reduce hunger or cravings any more than smaller portions. In other words, after 15 minutes, when all food was out of sight, everyone was equally happy.

A typical snack in the US contains about 264 calories (see Piernas and Popkin, 2010). This amount closely resembles the total calories consumed in the large portion size condition in our study (about 237 calories). Nevertheless, although participants in the small portion size condition ate considerably less (about 134 calories, which is about 51% of what people typically snack), they were equally tempted by the snacks. This shows that whereas large portions tend to increase food intake, smaller portions may make you equally satisfied. 

Going for the large portion size of their favourite food

How to stop eating when you are craving a food? One way is to make sure that there is less food in front of you in the first place. That is not simple. Large food portions are common in supermarkets, restaurants and even at home. Portion sizes of many foods have increased during the last decades and we are getting used to it. For example, snack foods and beverages are offered in increasingly large packages. Although many consumers find 'value for money' important, it would be better to stop the emphasis of getting more food for you money. Smaller portion sizes can help you limit the amount of food you eat.

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Snacking: what to do with the fourth meal of the day?

Snacking now constitutes 25% of calories consumed in the US, according to a study that was presented at the Institute of Food Technology meeting last month. This is about 580 calories per day, about the same size as a meal, according to professor Richard Mattes of Purdue University.

Why? There are more situations in which we are confronted with tempting food. Our internal hunger and satiety signals are weak, particularly when looking at large assortments of delicious treats. Refusing would require quite some self-control. What does not help, is that self-control is like a muscle in your arm, according to the well-known psychologist Roy Baumeister and his 'self-control-as-a-muscle-theory'. When used too intensively, it gets tired and is more likely to fail. Baumeister came up with the term 'ego depletion' to indicate that self-control is a limited resource. So the more you try to not give in to temptations the more likely you are to go for the 'forbidden' food in the end. Coupled with increased snack portion sizes available, it is not surprising that people get overweight. I guess there are two basic solutions: don't snack or snack smarter.

1)      Just do not snack 
When I was at Cornell last year, Jan Chozen Bays gave a very inspirational workshop about mindful eating. Mindful eating is paying full attention to eating without negative judgments. It is about being aware of physical and emotional sensations when eating. What struck me most during this workshop is that she said that we could learn to accept an empty stomach. It does not need to be filled immediately. Like Buddha, listening to the ebb and flow of hunger and desire, she explained. We are not used to that anymore, conditioned that we should not accept that nagging hungry feeling in our stomach. This reminded me of an old Dutch commercial with the slogan: 'Four o'clock: cup-a-soup, more people should do that'. Mindful eaters, however, do not look at the clock to decide what and when to eat, but listen closely to what their body is saying. Unfortunately, I still not that far in mastering the art of mindful eating...

Accept the 'four o'clock' feeling without snacking? (Still Cup a Soup commercial 1990s)

2)      Smart snacking: cut up your food 

You could switch to healthier foods, such as fruits. Another solution and probably more realistic for many of us is to cut up your food into smaller portions (maybe an interesting nudge?). David Marchiori and colleagues (see Journal of the American Dietetic Association) gave a group of study participants unlimited consumption from a bowl of candies. About half of the participants received candies that were cut in two pieces and the other half got the normal sized candies. Participants with the tiny candies ate about half compared to the other group. Although this was only a 60 calories difference, it showed that consumers typically view their consumption in numbers ('oh, I already had 5 candies) rather than quantities ('e.g. a handful). 

A related idea is to package your snacks in small-sized portions. A recent study of the Food and Brand lab gave one group of participants one large 400-calorie package of crackers and another group four smaller 100-calorie packs of the same crackers to eat during a television show. Results show that only overweight participants consumed more than double the number of calories when eating from the bigger package (384 calories versus 176 calories). Interestingly, all participants underestimated the number of crackers eaten. So, it is not the tracking of calories that is easier with a smaller package. Apparently, overweight people are more likely to rely on external cues (such as the need to open a new package) to stop eating, according to Wansink and colleagues.