How Thin People Make Other People Fat

Existing research suggests those trying to control their food intake should avoid dining with hefty companions with heaping plates. Not quite, says a new study. While the "I'll have what she's having" effect was confirmed in this experiment with college-age women, it was much more pronounced if the person supersizing portions was skinny. “They're big trouble,” a co-author tells Time, referring to "beanpoles with big appetites" eating in view of others.

In the experiment, college-age women were invited to grab a snack before a fake movie screening. When a size 0 actor in the room with them loaded her plate, the participants followed suit. When that actor put on a fat suit, the test subjects were a little more judicious. In another experiment, the actor took small portions, playing it both thin and overweight. Participants followed her lead when thin because, the researchers surmise, they aspired to her figure and thus aped her eating habits. But when she had the suit on and ate light, subjects ate more. If eating light doesn’t work for her, the theory goes, why should I try? (More scientific study stories.)