No matter how much you feel in control of your own eating, when you eat with other people, your food intake is likely to be affected.
Think back to the last time you ate a meal by yourself. What did you eat? And how much? Chances are you probably had a plan, and you probably stuck pretty close to it. You knew what you were going to eat and how much, you sat down with your plate of food, you ate and you finished. Now, think back to the last time you had a meal with another person or with a group. Did you eat the same way that you do when you eat by yourself? Social science research would say probably not.
The amount of food you eat at a meal is influenced by many factors. Among them are how hungry you are, how the food tastes, and even environmental factors like the color of the room, the lighting or the noise level. But there’s another big factor that can’t be overlooked—your dining companions can greatly influence how much you eat, too.
The research in this area is really interesting. What it tells us is that the amount we eat at a meal is influenced not only by the eating habits of the person we’re with, but also the number of people who are at the table. And even the gender of the person sitting across from you can have an impact.
Whether you’re aware of it or not, the way you eat in a social situation (as opposed to what you do in private) is influenced by something called modeling. In essence, you pattern your eating behaviors after the behaviors of those around you. As you eat with other people, their behavior influences your perception of what is the “right” amount of food to eat in a certain situation, and by modeling them you tend to follow suit.
When you eat by yourself, it’s a bit easier to pay attention to your body’s signals that tell you when you’re hungry and when you’re full. That’s one reason why it’s often easier to control your intake when you eat alone. But when you’re modeling other people’s eating behaviors, it’s as if these internal signals have been dialed back.
Interestingly, though, the modeling effect seems to be stronger when your dining partner is a light eater, rather than a heavy eater. What this means is that you’re more likely to model the behavior of someone who eats lightly, and less likely to eat more than you normally would just because your dining companions are over-indulging.
That’s good news because it suggests that when you eat meals with light eaters, it may help you to keep your portions in check, too. At the same time, it also suggests that when you share a meal with a heavy eater, there’s less of an influence on you to keep pace.
The gender of your dining partner may also influence how much you eat. The way men and women approach eating and food is a huge topic, and much too large a topic to be addressed here. But in general, women tend to model eating behaviors of others at the table more so than men do. The reason for this isn’t clear. But one thought is that women may be more concerned with how others view their eating habits than men are—at least when they’re dining with companions.
However, women eat pretty consistently. Whether they’re dining with other women or dining with men, their overall intake doesn’t change that much. On the other hand, men tend to eat larger amounts of food when they dine with women than they do when they dine with other men.
Perhaps this explains a finding from a recent study1 in which women said that when their dining companion was male, they estimated that they ate more than they actually did, and reported feeling as if their meal was rushed. This didn’t surprise me. When I was teaching a few years back, I asked a group of college undergrads to write down an observation about the eating habits of the opposite sex. Most of the men said that women “hardly eat anything” or “just eat salad.” But the women overwhelmingly said the men eat—and I quote here—“like pigs.”)
The number of people you eat with can have a dramatic influence on how much you eat—partly because when you’re with a group, it’s easy to lose track of what you’re eating. While you’re enjoying the company and the conversation, you might mindlessly grab handful after handful of tortilla chips from the communal basket, or swallow another scoop of mashed potatoes without even realizing it.
We also tend to linger at the table when we’re with others. We’re going to stay at the table until everyone has finished, which just means there’s more time to keep eating and eating. If you’re a fast eater and the first one to finish your meal, you might dish up another plate of food. So, the slower folks at the table don’t feel as if they’re dining solo.
And the larger the party at the table, the more you’re likely to eat. One widely cited study2 found that, compared to eating a meal alone, eating with one other person increased meal size by 33%. With two other people, the meal was 58% larger, and with three other companions it was 69% larger. By the time there are seven or more people at the table, meal size nearly doubles—averaging 96% larger than a meal eaten alone. The reason for this isn’t entirely clear, but it likely traces back to the fact that the more people there are at the table, the longer the meal tends to be.
If you’re trying to watch what you eat, you might be thinking that you’re better off just eating alone—or only with those who tend to eat less than you do. But let’s be real—dining with other people is a pleasure. As long as you’re aware of how others might influence you to eat more than you should, you can make an effort not to be persuaded. Here are some tips:
1Knifflin et al. Evol Psychol Sci Published online November 10, 2015.
2J. deCastro. Nutrition 16:800, 2000.