Eating with others tends to increase the amount of food we consume, by one-third to three-quarters more total calories. In one week-long study involving 63 women, researchers found that the average meal eaten alone consisted of 410 calories, while the average meal consumed with others was 591 calories. In another study, published in Appetite, the 78 women studied ate between 34 and 45 percent more calories when they consumed their food in a social setting.
So we know that our friends can persuade us to eat more, the question is: Why? Elizabeth Somer, author of Nutrition for Women (Owl, 2001), says, “There are a number of factors at play here. It could be that your guard is down, or that you’re focusing on your socializing so you end up unconsciously eating more food.” Also, when friends are involved, we tend to eat in restaurants where portions are bigger. Somer also believes there may be anthropologic reasons behind eating more when in a group. “There very well could be some instinctive thing based on thousands, if not millions, of years of evolution. When food is around, you need to compete with the group to make sure you’ve got your share. It’s an instinctive drive.”