By Peter M. Vishton, Ph.D., William & Mary

Edited by Kate Findley, The Great Courses Daily

Do you find yourself eating less when you’re surrounded by friends? Or perhaps you eat more. Peter Vishton, Ph.D., explains the psychology behind group behavior and caloric consumption.

Sweeteners and Obesity

Researchers have identified a lot of factors that might be responsible for our modern obesity epidemic. One factor that hasn’t been fully explored, though, is social eating patterns. These patterns are subconscious drivers that lead us to either eat more or less in the presence of a group.

First, let’s start with the most familiar links to obesity. Many studies point to the dramatic increase in our use of corn-based sweeteners such as high-fructose corn syrup. 

Corn-based sweeteners are cheaper than the cane-based sugars that were more typically used in the past. Manufacturers like the lower cost, since lower cost means greater profit. 

Plus, corn-based sweeteners taste very sweet. A typical consumer either likes, or doesn’t even notice, the difference in taste.

The evidence is mixed, but some studies suggest that when you consume high-fructose corn syrup, it reduces your brain’s normal response to leptin. You consume the calories, but your body doesn’t signal an appropriate “stop eating” signal.

This resistance to leptin can, over time, lead to substantial weight gain. Similarly, the obesity epidemic might be caused by the rise of processed, sugary, fatty foods.

Less Socializing, More Eating

Additionally, we spend more time in sedentary activities such as working in front of computer screens and playing video games than we have in the past. The reduction in physical activity, especially during childhood, seems partially responsible.

There’s another cultural change in our eating behaviors, however, that doesn’t get discussed very often. Modern eating has become less and less of a social event over the past several decades. 

If you sit with your family and friends around a table for a meal, you eat. However, you also spend time talking, telling stories and jokes—generally socializing.

If you eat like this on a regular basis, then you’re more likely to pause and take breaks during your meal. These breaks give your body an opportunity to process whether or not it is satiated—it often takes 20 minutes from the time our body reaches this point for it to send a signal to our brain that we are full.  

If you have a social event three times a day—around breakfast, lunch, and dinnertime—and at that social event you happen to also have some food, then you’re probably already taking more than 20 minutes to eat.

As people in our society have drifted more in the direction of eating on the go, however, we aren’t just missing out on the social event itself. We’re typically eating more, almost always without even realizing it. 

So if you’re eating, make sure you stop for 20 minutes to let your body catch up at some point early in the meal. Alternatively, make the meal a slower, social occasion. Either way, you’ll eat less without having to suffer through any additional hunger.

Gender-Based Social Patterns and Eating

There’s a related tip that’s emerged from a few recent studies: If you’re a woman who wants to reduce your calorie intake, eat with men. Molly Allen-O’Donnell, then a graduate student at Indiana University of Pennsylvania, and her colleagues performed a set of studies in which they watched people ordering food in restaurants. 

When women ordered food in all-female groups, they tended to order and consume an average of about 833 calories worth of food. When women ate with a man in the group, they ordered less—only about 721 calories. When there was a man around, women seemed to eat about 13 percent less.

The researchers suggested some reasons for this, though it’s mostly speculation. Perhaps women want to appear more ladylike and are thus less likely to gorge themselves. 

Maybe women are socialized over the course of their lives to do this—that is, maybe they’re just imitating what they’ve seen other women doing in the past. Maybe there’s some ancient mating-related behavior in which women who appear to not need as much food are seen as more desirable as potential mates.

Interestingly, the effect worked in the opposite direction for men. Men tended to consume more calories in the presence of women than in all-male groups.

When a man ordered food in a mixed-gender group, he tended, in these studies, to eat about 1,162 calories, compared to 952 calories in an all-male group. That’s about 18 percent less. In this case, the researchers hypothesized that perhaps the male was attempting to assert his masculinity in the presence of women by eating more.

For women wanting to lose weight, then, eating in a mixed-gender group might be the best course of action, while a man might want to do the opposite and eat surrounded by other men. This shows how social eating patterns can actually influence how much we consume.

This article was edited by Kate Findley, Writer for The Great Courses Daily.

Dr. Peter M. Vishton is Associate Professor of Psychology at William & Mary. He earned his Ph.D. in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.