Buffet Diners May Squash Healthy Food Choices If Line Leader Is Overweight

buffet
We may like to think eating healthy is just a matter of will power, but the social dynamics of the buffet say otherwise. Zhi Yong Lee, CC BY 2.0

We already know the size of our plate influences how much we eat, just like the presentation of the food and, of course, how hungry we are. A new study adds to that list, claiming overweight people actually compel us to eat more when we eat with them.

Buffet lines are a dangerous place. They may save your wallet from emptying, but a raft of social science research argues the relationship between people knowing how to eat healthy and actually doing so is tenuous. Our food choices, psychologists are finding, come more from what others are eating than what our diets dictate.

These are the latest ideas to emerge from Cornell University’s Food and Brand Lab, where food research is (ahem) their bread and butter. When they tested to see how a stranger’s weight influenced people’s decision to eat more unhealthy pasta, they found regardless of what the heavier person chose — either pasta or salad — participants helped themselves to a larger portion.

“Both the body type and serving behavior of an eating companion may influence the quality and quantity of our food intake,” wrote the research team, led by psychologist Mitsuru Shimizu, of Southern Illinois University-Edwardsville.

Their experiment went like this: A woman of a healthy weight stood at the front of a buffet line and portioned out varying amounts of food. In one condition, she heaped a lot of salad and little pasta onto her plate, while in another she doubled up on the pasta and skimped on the salad. Among the 83 subjects, she stayed conspicuous by dropping a fork and asking, “Do I need to use separate plates for pasta and salad?”

In separate experiments, researchers put the woman in a fat suit that added roughly 50 pounds to her frame. She performed the same experiment as before, with both conditions. But to the researchers’ surprise, the amount of food she took and the ratio of healthy salad to unhealthy pasta had no effect on how much pasta the people behind her took: The majority took more.

To the researchers’ mind, the findings were clear: Overweight dining companions compel us to eat more. But the question of why is still elusive. One theory posits we tend to eat more because we view the overweight person as license to indulge. I’m not as big as that person, we may think. I can afford to eat more of the unhealthy stuff.

Another theory is based off the team’s finding that people tended to eat less healthy specifically when the woman was overweight and took salad for herself. People may have the tendency, in other words, to shirk a healthy diet if they see someone who already is trying that diet but apparently failing. It’s the mindset, Why should I eat salad if it can’t even help her lose weight?

These biases aren’t all that new. A study published in November of last year found people tend to choose healthy or unhealthy snacks for other people based on keeping the social order. When Duke University researchers asked a group of people to choose a snack for themselves and for someone else, they tended to choose different snacks only when the other person looked to be of a healthy weight. People explained their choice by saying giving a healthy snack to an overweight person and keeping the junk food would be offensive, but so would keeping the healthy snack and offering the junk food.

Other research has found buffet lines can sway people’s food choices depending on what the first item up for grabs is, suggesting people have a tough time sticking to eating healthy if the prospect of eating at all is on the table. The upshot is buffets are social, which means people will naturally feel the effects of other people’s decision making. Healthy food choices aren’t made in a vacuum; they must be considered with a dose — or, if the person ahead of you is large, a heap — of mindfulness.

Source: Shimizu M, Hancock K, Wansink B. In good company. The effect of an eating companion's appearance on food intake. Appetite. 2014.

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