People eat more with friends and family than when dining alone and evolutionary psychologists have defied Occam's razor and come up with an unnecessarily complex explanation for why, speculation that it could be an ancient throwback to our early ancestors' approach to survival.

Ancient hunter gatherers shared food because it protected against periods of food insecurity and the authors suggest that this may be a biological survival mechanism that still persists today, leading to people eating more with friends and family. As support for their beliefs they note other claims that those eating with others ate up to 48% more food than solo diners and women with obesity eating socially consumed up to 29% more than when eating alone.

The simple explanation that is more valid; people eat more a friends and family events because those are celebrations. Yet papers don't get written based on that so the authors stretch credulity by finding 42 papers that are already weak observational "studies" (read: surveys) about social dining to promote the only conclusion their cart-before-the-horse methodology will allow; that eating with others is more enjoyable and enhanced reward from social eating increases consumption.

Or they get together at Thanksgiving.

The problem evolutionary psychology has always faced is that it wants to take behavior and bypass a whole lot of science in calling it science. So they invoke biology, but pushing behavior a step away helps little because there was no biological mandate in the past either. Some helped others, some did not, just like now. Once oxen came into popularity in agriculture there became a very clear divide between the rich (who had oxen and could farm 10X as much land) and those without. If this evolutionary psychology belief in sharing were real, and part of a basic need, humans would have stayed within the very narrow range of the work each person could do and simply shared.

Despite being on shaky ground, they argue that sharing food was a survival mechanism that protected against periods of food insecurity and that this survival mechanism may still persist today. But even that is not right. Food was a sign of wealth, sharing it was never an innate biological mechanism. Only rich people were fat in the past and that would not be the case if sharing were a survival mechanism. Celebrations were rare and involved food because of their rarity, the same way people often saved their best clothes for church.

And their beliefs that people eat more during celebrations because social norms penalize overating when alone are in defiance of existing reality. Western countries have rampant obesity and these are not rich people having celebrations every week, it is overwhelmingly poor people who can afford food and televisions and choose to over-indulge in both.

Dr. Helen Ruddock, from the School of Psychology at the University of Birmingham, said, "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."

Which has an Occam's razor explanation as well. People who go to a lot of events are simply sick of them, or they are getting pictures taken, or they don't want to get fat. That means there is no evolutionary factor, or they would not behave that way. Yet the authors suggest that women have an innate need to be desired by men, so they won't eat much, and obese people don't want to be judged, so they don't eat much, but both groups pig out when with friends.

They invoke the 'evolutionary mismatch' of inherited foraging strategies that no longer serve their former purpose, but the mismatch is in how they proceeded from false assumptions.

People get together with friends and family during celebrations. It's not that complex, and it is not an evolutionary mandate.