Which counts more? Calories or companions?

First published in the W. P. Carey magazine, Fall 2016.  

Research by Carola Grebitus, Assistant Professor of Agribusiness

Less than one-third of U.S. adults over age 20 are “normal” weight or under-weight, according to the U.S. Department of Health and Human Services. More than a third of the population is obese, and many sources think dining out contributes to the problem. Recent research from Tufts University might explain part of the reason why. After analyzing meals from hundreds of restaurants across the U.S., scholars found that 92 percent of entrée portion sizes topped recommended calorie requirements for a single meal. At American, Chinese and Italian restaurants, calories per meal averaged 1,495. To put this in perspective, U.S. government guidelines suggest an inactive woman simply multiply her weight by 13 to find her proper daily calorie intake.

For a 120-pound woman, that’s only 1,560 calories per day. Still, we eat out more than ever before. As of March 2015, the amount of money Americans spent at restaurants and bars overtook grocery store spending for the first time since the U.S. Department of Commerce started tracking the data in 1992. To help battle the nation’s bulge, the Affordable Care Act mandates that any restaurant with more than 20 sites post menu labels revealing calorie counts. The efficacy of such approaches is uncertain, according to Assistant Professor of Agribusiness Carola Grebitus. Varying studies have varied results, she says. Even when menu labeling was correlated with lower calorie consumption, Grebitus says some studies found reductions to be modest: 10 to 20 calories per meal. Since dining out rarely means dining alone, Grebitus investigated the impact dining companions have on calorie consumption. Her research uncovered two findings. First, menu labeling can have impact, provided you notice it. Second, your calorie intake can be affected by more than just the menu. The characteristics of your dining companions have influence, too.

Lunch-counter culture

Grebitus conducted her study in an on-campus dining hall at Arizona State University. It’s a cafeteria-style eatery with plenty of healthy options — salad bars, fresh fruit, healthy soups and more — as well as lots of not-so-healthy choices, such as pizza and burgers. One meal ticket buys any and all of those things. It’s an all-you-can eat smorgasbord. Unlike most buffets, this one comes with detailed menu labeling similar to the informative text on the side of a cereal box. Restaurant goers can track calories as well as grams of protein, total fat, saturated fat, carbohydrates, fiber and sugars. Vitamin information shows up, too.

The menu labeling displays the percentage of daily requirements for vitamins A and C, plus calcium and iron. For those who suffer food allergies, the presence of things like dairy, soy or peanuts also is listed on the labels. Grebitus applauds this cafeteria’s menu labeling and its detail. “Most of the time, we tend to overeat when dining out, especially when it’s buffet style,” she says. “Usually, you don’t really know how many calories something has, but in that dining hall you can see that nutritional information.” You can see it, but that doesn’t guarantee you will look at it or pay any attention to it at all. In the research Grebitus conducted, people eating at tables with four diners each were asked to fill out detailed questionnaires about their own body characteristics — weight and height — as well as how they knew their companions. Were they friends or new acquaintances? Naturally, people also reported what they ate. In addition, the diners had to let Grebitus and her fellow researchers know if they’d happened to notice the menu labeling and whether it influenced their food selection. “With regard to the menu labeling, 46 percent of all participants noticed the nutrition facts,” Grebitus wrote along fellow researchers Dan Wang, a master’s degree student at W. P. Carey’s Morrison School of Agribusiness, and Christiane Schroeter from California Polytechnic State University, all co-authors on a recently completed paper about this study.

The research team also noted that 31 percent of those who noticed the menu labeling — or 15 percent of all study participants — used the information when choosing the items they ate. According to Grebitus et al., previous studies also found that only about half of all restaurant goers notice the menu labeling that’s available. In the study, more than 80 percent were students, and 17 percent were staff, faculty or visitors to the university. In this youthful study population, half of all respondents were of normal weight, which means they had a body mass index (BMI) of 24.9 or lower. What’s more, 43 percent of all the table groups had no overweight members. In other words, thin students tended to eat with other thin students. Meanwhile, 46 percent of the study participants were overweight or obese according to BMI standards and three out of four individuals were obese in 36 percent of the table groups. In addition, 88 percent of the people who filled out the questionnaire indicated that they were eating with at least one friend at the table.

I’ll have what she’s having

Some of the questions subjects answered related to whether they noticed other people’s food choices or discussed the various selections. Such behaviors, it turns out, are enough to impact food decisions. “You can be eating when you notice something that someone else in your group is eating and you think, ‘that looks good,’” Grebitus explains. “Then you want to have some, as well.” Or, your friend might talk you into extra chow. Grebitus says she used to dine with one friend she could always count on to suggest dessert after lunch, and she’d often cave in. “Even if I wasn’t hungry anymore, he’d put this idea in my head, and then I wanted cake. It was really good cake.” Suggestions are powerful, but more potent is the indirect social influence brought on by eating with people who are obese.

Grebitus says research shows obese people who eat together tend to become more obese over time. She says “probably people are more comfortable to eat more when other group members eat more as well. They might even feel encouraged.” In the study, this behavior showed up multiple ways. Grebitus and her team calculated caloric intake based on a check-off list of foods available at the cafeteria. When study participants ate high-calorie foods like pizza and pasta in a group with obese peers, calorie intake increased. If the individual answering the questionnaire was obese but eating low-calorie foods like salad, calorie intake dropped 219 calories, but if there was another obese person at the table, it only dropped 145 calories. As Grebitus explains, “Based on our results the presence of someone obese in a group increases your calorie intake if you are eating something unhealthy. Noticing someone else’s food also increases calorie intake. However, if you notice the menu labeling, you will probably eat less.” In their calculations, the researchers simplified their tracking of healthy versus unhealthy eating by watching consumption of pizza and pasta for the unhealthy items and salad for the healthy proxy. Among those who paid attention to menu labeling, calorie consumption from pizza or pasta was 294 calories less and calorie intake from salad was 154 calories more per meal.

Knowledge is healthy

All of this makes Grebitus more strongly convinced that menu labeling has impact and should be supported, but she also thinks it’s not quite enough to turn the tide on obesity statistics. She calls menu labeling the first step. What should be the second step? “I think nutrition education,” she says. “What we didn’t ask but could in a follow up study was why people didn’t use the menu labeling,” she adds. “Was it because they don’t understand what it means? Is it because they don’t have context? Eating 1,000 calories probably doesn’t mean much if you don’t know that you shouldn’t eat more than 2,000 a day.” Grebitus concludes that lack of awareness is the key problem. She’d like to see education to “change a person’s perceptions and encourage more conscious eating” so people ask themselves if they’re still hungry before taking that next bite or ordering the cherry pie after dinner. And, of course, she’d like people to pay attention to the company they’re eating with, as well. “The people that we’re eating with can influence what and how much we are eating. It’s important that we are aware that this can happen — and rather ask our friends to support us making healthy food choices instead of making us eat more cake.”  

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