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When It Comes to Calorie Consumption, Is Knowledge Power?

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Credit: Terrence Horan, MarketWatch

The other day, I went to order lunch from a local chain restaurant. Half a turkey sandwich and a small cup of soup sounded like a good, appropriately sized, warm meal for a wintery day. As I placed my order, a kiosk tallied the calories right before my eyes: 400 for the sandwich and almost 300 for the soup…

Hmm. That seemed like a lot. Maybe, I thought, if I remove the bacon from the sandwich… and get a smaller soup…? “You know what? I’m sure it’s fine,” I told myself, and completed the order.

Over-consumption of calories has been a key driver of rising rates of obesity, and dining out is thought to play a significant role as people often substantially underestimate the calories in prepared foods. Restaurant menu labeling has been implemented in several cities and states and was included in the Affordable Care Act. By May 2018, chain restaurants, grocery stores, and other food establishments with 20 or more locations will be required to post calorie information on their menus. The hope is that making such information more visible will encourage consumers to choose – and restaurants to offer – lower-calorie items. But will it work?

We talked with Christina Roberto, PhD, director of the Psychology of Eating and Consumer Health (PEACH) Lab, about what the latest research shows on how knowing calorie information affects what people order and how much they consume.


Q: Calorie labeling is relatively new. Has there been enough research to know if it works?

A: In short, the jury is still out on whether or the degree to which menu labeling encourages lower-calorie purchases and whether that will translate to a healthier population. But, there has been some research on the topic and we’re starting to learn more about how it affects consumer decision making in different settings like fast-food restaurants, cafeterias, and full-service chain restaurants.

We recently published a study that looked at all of the available research to date, and overall, although there’s little evidence to suggest that calorie labeling is leading to lower calorie purchases at fast-food restaurants, there are more promising findings that it may influence consumers at certain types of restaurants, such as full-service sit-down restaurants, coffee shops, and cafeterias.

Q: Why would that be?

A: it’s possible that calorie labeling may have more of an effect in certain settings because of the types of people who frequent those establishments, or differences in the psychology of ordering based on the restaurant setting.

For example, it could be that coffee chains, full-service sit-down chains, or fast-food outlets that market themselves as “healthy” attract consumers with higher incomes, education levels, and/or health consciousness who are more likely to pay attention to or be influenced by calorie labels. Some of the studies we looked at showed that awareness or use of menu labels is higher among certain consumers, such as women and those with higher incomes and health consciousness.

It’s also possible that calorie labeling doesn’t affect fast food patrons as much because they go to these restaurants already knowing what they want to order, while full-service sit-down patrons may spend more time reviewing the menu before making their decisions.

We also saw evidence that calorie labeling can promote lower-calorie choices in cafeteria settings. That could be because people eat there more regularly, like in a cafeteria in the work place, and are less likely to view the meal as a “treat” compared to dining out.

The bottom line is that we have some ideas about when calorie labeling may be more effective, but the mixed results we see, may be due in large part to issues with study design.

Q: Can you elaborate on that? Were there some studies that were more promising than others?

A: Yes, eighteen of the studies we examined evaluated calorie information in real-world restaurant settings. These varied greatly in design, with only one randomized control trial (RCT) and one quasi-real-world RCT. Seven studies used natural experiments evaluating menu labeling before and after implementation in an intervention and control city, while seven other studies only looked at changes before and after menu labeling was implemented in a city. Finally, two studies compared labeled versus unlabeled restaurant locations at the same point in time.

The strongest research design to evaluate menu labeling is a randomized controlled field experiment. Unfortunately, we were only able to find one of those, and the sample size was too small to be able to detect even moderate effects. But the study with the next strongest design found that calorie labeling was associated, on average, with a 15-calorie reduction per order at a coffee shop chain. And although there was only one real-world, full-service chain restaurant analysis with an adequate sample size, that study found that calorie labeling was associated with a 150-calorie reduction per order.

So the bottom line is that evaluations of menu labeling in different settings are mixed, but because much of the research is plagued by small sample sizes and sub-optimal study designs, what we really found is that there’s a considerable need for more research in this area. Data from RCT field experiments and natural experiments with large sample sizes testing menu labeling are needed, especially at full-service chain restaurants.

Q: As more restaurants are preparing to include calorie information on their menus, what, if anything, can be done to improve the impact labels have on decision making?

A: Well, presumably, making calorie information easier to understand and more accessible to a greater range of individuals would increase the reach and impact of the information. Some studies have shown, for example, that using traffic light systems to show which menu items are lower-calorie (indicated by green lights) and which are higher calorie (indicated by red lights) can cut the number of calories ordered by ten percent—but these types of labels don’t always outperform calorie information alone. We really need more real-world RCTs with large enough sample sizes to know for sure.

But rather than just focus on how calorie labels directly influence consumers, we were also interested in how labeling might influence what restaurants offer on their menus. Although the preliminary evidence suggests that calorie labeling regulations may be correlated with healthier restaurant offerings, the small number of studies and differences in study design make it difficult to draw conclusions at this point.


According to Roberto, research suggests that in order to return to 1970 levels of excess weigh in the population, adults need to consume 220 fewer calories daily, while children need to consume 165 fewer calories daily. Reducing consumer purchases in chain restaurants by even a small amount may help reduce this excess calorie intake.

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