By Amanda Gardner
WEDNESDAY, February 1, 2012 (Health.com) — People sitting at the table with us have a subtle yet powerful influence on our eating habits that in some cases may lead us to overeat, especially if we're trying to be agreeable or make a good impression, new research suggests.
In a study published today in the journal PLoS One, Dutch researchers invited 70 pairs of women to dine together in a lab set up to look like a restaurant. The women, they found, tended to take bites of food at roughly the same time and mimic each other's overall eating behavior.
This mirroring was three times more common at the beginning of the meal than at the end, however, which suggests that the women, who were strangers, may have been trying to make a favorable impression on each other.
Researchers say the findings help explain previous studies showing that people tend to adjust their food intake—up or down—to match that of their eating companions, and tend to eat more with others than when dining alone.
"This demonstrates the power of social influence over food intake," says lead author Roel Hermans, a doctoral candidate in developmental psychopathology at Radboud University Nijmegen, in the Netherlands.
"It's important that people become aware of these factors," Hermans adds. "As long as such important influences on intake are not wholeheartedly acknowledged, it will be difficult to make healthy food choices and maintain a healthy diet, especially in eating contexts in which people are often exposed to the eating behavior of others."
Although Hermans and his colleagues can't say for sure that the study participants were matching bites in order to win each other over, past research suggests that people use this type of mimicry when they're trying to get other people to like them. This may actually be a sensible strategy, since at least one study has found that people aren't as well-liked by their dining partners if they eat conspicuously small amounts of food.
A second study published today provides more evidence for the idea that some people eat to create a good impression or to make another person feel comfortable.
Next page: "People-pleasers" give in to food pressure
In that study, which appears in the Journal of Social and Clinical Psychology, college students who were identified as having a docile, eager-to-please personality were more likely than other students to eat M&Ms—and eat more of them—when someone offered them the candy.
Students with this so-called "people-pleasing" disposition were also more likely to recall a time in the recent past in which they ate more than they wanted in order to put another person at ease. If a friend or family member was overeating or indulging in junk food, for instance, they were generally inclined to join in.
"The people-pleasers were more likely to say…'I felt this pressure to eat. I was distressed about it. I wanted to appease that person. I ended up caving in and eating more,'" says Julie Exline, PhD, the lead author of the study and an associate professor of psychology at Case Western Reserve University, in Cleveland.
Exline's study is far from conclusive. Research that relies on the memory and perception of the participants has inherent limitations, and in this case the incidents recalled by the students took place an average of four months earlier. Moreover, like the Dutch study, the M&Ms experiment involved strangers and was conducted in a laboratory setting that may or may not translate to the real world.
Likewise, Hermans' research provides no clue as to whether family members, friends, or acquaintances are more or less likely than strangers to mimic each other's eating. "If behavioral mimicry represents an attempt to ingratiate with others, we would expect less behavioral mimicry among familiar people than among strangers," Hermans says. "This should be tested in future studies."
Neither study looked specifically at how social interactions involving food might affect weight gain or obesity, but the findings do fit well with research suggesting that obesity appears to spread through social networks, Exline says. People who have overweight or obese friends and family members are more likely to be heavy themselves, that research found.
If you suspect you might be a people-pleaser, you may want to be especially mindful of your eating habits in social situations, Exline says.
"If once in a while you're at a party and there's pressure to eat, that's probably not going to have a big effect on overall quantity of eating," she says. "But if you're around people a lot and are facing this situation every day, it could be problematic."