Why do people eat more when dining with friends and family?

Do you find yourself particularly full after dinner with a group of good friends?

Researchers say there’s a scientific reason behind this. A new study published in The American Journal of Clinical Nutrition claims that eating more when you are surrounded by family and friends could be a result of "social facilitation”. Researchers from the University of Birmingham, led by Dr. Helen Ruddock, outline a number of evolutionary and psychological hypotheses that explain the human tendency to consume more when they are eating with other people. 

Experts analysed more than 40 research studies that used experimental and non-experimental approaches to examine food intake. The study confirmed the hypothesis: people eat more when they are with family or friends and tend to eat less when with people they don’t know.

Eating with other people

Previous studies have demonstrated that people eat 48% more when in familiar company than when dining alone. Particularly popular foods to consume in social contexts are those rich in fat and protein, such as pizza, burgers, and other meat-based products. 

A number of variables tend to impact social food choices. Gender, obesity, and how well the group of people eating together know each other are believed to be the biggest determining factors when it comes to choosing food. 

Research also found that women tend to eat less than they would normally eat alone in certain social situations, especially in front of men - regardless as to whether they were strangers friends. Overweight people are also more likely to be found eating smaller portions in public According to the study, both women and overweight people eat 18% less food when in a group compared to eating alone.

Dr Helen Ruddock says: "People want to make a positive impression on strangers. Selecting small portions can provide a way of being respectful. This may be why ‘social facilitation’ is less common among groups of strangers dining collectively.”

Food can be a sensitive issue, and both restriction and overeating can lead to social stigma. If we fear being judged, we will most err on the side of caution when it comes to eating in unfamiliar social settings.

Ruddock continued: "Previous research suggests that we often choose what (and how much) to eat based on the type of impression we want to convey about ourselves. The evidence suggests that this may be particularly pronounced for women who eat with men who want to impress. It is also a common characteristic of overweight people who want to avoid the possibility of being judged for overeating."

The team of researchers believe that some aspects of food related behaviour is related to natural instincts. Certain urges can be traced back to our ancient ancestors’ survival tactics. Thousands of years ago, hunter-gatherers made a habit of sharing their found food and eating socially, to ensure everyone had the chance to eat, to prevent starvation if food sources  were scarce. 

Ruddock clarifies the theory: "What we describe as 'social facilitation' can be seen as a natural by-product of the social exchange of food, a strategy that would have played a critical role in our ancestral environments. This also explains why it is more likely to occur in groups with people who know each other well.”  

The majority of people living in the modern first world have no problem accessing food on a daily basis, meaning life is very different to that of our ancestors. In fact, for many people, the problem is that we’re now living in a ‘food-abundant’ society. Researchers suggest that humans may still be acting on psychological mechanisms that are ingrained in us from our hunter-gather days, when found to be eating in groups. Eating in the presence of others is also generally considered more pleasurable, so there may also be a psychological reward for social eating, which can lead to over-consumption.

So, the next time you sit down for a family meal, you may want to pay attention to the number of dishes and portion sizes you’re planning to consume, because if you’re not careful you may find there’s no room for dessert.

Reference: Helen K Ruddock, Jeffrey M Brunstrom, Lenny R Vartanian, Suzanne Higgs. A systematic review and meta-analysis of the social facilitation of eating. The American Journal of Clinical Nutrition, 2019; 110 (4): 842 DOI: 10.1093/ajcn/nqz155