Thin friends might be bad for your diet

Students in study mimicked behavior of heavy-eater who was slim - but not one who was obese

By: By Neil Offen | DURHAM HERALD-SUN<br> </br>MCCLATCHY-TRIBUNE EXCHANGE
Published: August 27, 2009

DURHAM

Don't just be careful about what you eat.

You also should pay attention to whom you are eating with -- particularly if you're dining with thin people.

According to new research from Duke and other universities, thin friends who eat a lot could put your waistline in danger.

A study of 210 college students found that people tend to consume an amount of food similar to what's consumed by the person they are dining with.

But the influence of who you are eating with diminishes if that person is obese, said the researchers.

"We believe that's true because normal-weight individuals find obese others to be essentially members of a stigmatized group," said Gavan Fitzsimons, a professor of marketing and psychology at Duke's Fuqua School of Business. "As a result, they consciously shift away from being influenced by anything they do, perhaps most so in the domain of food."

The researchers used snack foods, an obesity prosthesis and the ruse of a study related to movies to track how students' food consumption was influenced by a companion. Their findings appear online this week in the Journal of Consumer Research.

The students were recruited, believing that they were participating in a study about movie-watching.

At the research lab, each student was teamed with another student taking part in the same study.

The other student was in fact a member of the research team whose size was manipulated to make her appear to be either size 0 and 105 pounds (her natural build), or size 16 and 180 pounds (when wearing the obesity prosthesis, a rubber suit that made her look much larger).

All the students were offered snacks to enjoy while viewing a film clip. The undercover researcher was served first, and helped herself to either a large or small serving before the student participant was offered the same bowl of food.

In all cases, the amount of food the students took was influenced by the portion size chosen by the undercover researcher, regardless of her size.

"Most participants took a portion similar to what the researcher served herself," said Brent McFerran, an assistant professor of marketing at the University of British Columbia, which was also involved in the study. "However, it is clear that how much food each person took, and how much they ate, depended on whether their companion was thin or obese."

Although their serving sizes mimicked those of the researcher, the researcher's influence was less when she was obese.

If the thin researcher ate a lot or only a little, the participant followed suit. But when the researcher was obese, participants adjusted the amounts they ate and diminished the influence the researcher had on them.

"In terms of consumer health, our findings indicate that the size of the person you dine with matters much less than the size of the meal they order," Fitzsimons said. "If a heavy-set colleague eats a lot, you are likely to adjust your behavior and eat less. But a thin friend who eats a lot may lead you to eat more than you normally would."

In many cases, the researchers wrote, "the most dangerous people to eat with are not those who are overweight, but those who are thin but heavy eaters."