BIRMINGHAM, England — It happens to everyone from time to time; you’re out to dinner with friends, order one too many appetizers and end up feeling overstuffed afterwards. Or you’re at a relative’s home for a holiday meal and by the end of the evening, your waistline seemingly grew a few inches. If you’ve ever noticed that you tend to eat more in the company of friends or family than when you dine solo, you’re not alone. According to a new international study conducted at the University of Birmingham, people are inclined to eat more when surrounded by others.
Previous studies had already found that those eating in the company of other people consumed 48% more food than diners eating alone, and obese women eating socially ate up to 29% more food than when eating alone. Now, after evaluating 42 previous studies into the subject, researchers from both England and Australia have concluded that eating socially has a powerful impact on increasing the amount of food we eat. This is described as a form of “social facilitation,” or a tendency to act differently when around other people.
So, where does this natural inclination to eat more socially come from? Researchers believe it can be traced all the way back to our ancient ancestors’ survival tactics. Thousands of years ago, hunter-gatherers made a habit of sharing their found food and eating socially, a practice intended to protect against food scarcity.
The study’s authors say it is likely that these tendencies have remained in our makeup for a few different reasons; eating with others is more enjoyable and rewarding, it’s much more socially acceptable to overeat among friends than it is to do so alone, and sharing or providing food with others is associated with praise, recognition, and stronger social bonds among friends and family.
All that being said, researchers say that dining with strangers or new acquaintances does not produce the same effect.
“We found strong evidence that people eat more food when dining with friends and family than when alone. However, this social facilitation effect on eating was not observed across studies which had looked at food intake amongst people who were not well acquainted,” explains research leader Dr. Helen Ruddock in a release. “People want to convey positive impressions to strangers. Selecting small portions may provide a means of doing so and this may be why the social facilitation of eating is less pronounced amongst groups of strangers.”
“Findings from previous research suggest that we often choose what (and how much) to eat based on the type of impression that we want to convey about ourselves. Evidence suggests that this may be particularly pronounced for women eating with men they wish to impress and for people with obesity who wish to avoid being judged for overeating,” Dr. Ruddock continues.
Of course, food is much more readily available today than it was at the time of hunter-gatherers, but researchers say these mechanisms are still guiding our behavior at a subconscious level. This has led to an “evolutionary mismatch,” as the study’s authors call it, in which a behavior that once served an important purpose is now simply causing unhealthy eating habits.
But, why did early humans develop this behavior in the first place? The research team say similar eating habits have been observed in various animal species, suggesting it serves a universal purpose. They theorize that due to food being particularly scarce in ancient times, either overeating or wasting food would have been a grave indiscretion worthy of ridicule and punishment. So, eating socially, and being sure to eat about the same amount as everyone else in the group, may have been a way for early humans to avoid being accused of wasting food. This could explain why people to this very day still tend to eat more than they are comfortable with when dining with others.
“A solution to this tension may be to eat at least as much as others in the group – individual members match their behavior to others, promoting a larger meal than might otherwise be eaten in the absence of this social competition,” Dr. Ruddock says. “What we describe as ‘social facilitation’ can be seen as a natural by-product of social food sharing – a strategy that would have served a critical function in our ancestral environments. This also explains why it is more likely to occur in groups with individuals who are familiar with each other.”
The study is published in the American Journal of Clinical Nutrition.