Dining with heavier friends could prompt you to eat more than you normally would.

New research conducted by Cornell University demonstrated how the weight of the people dining with (or near) an individual could have an effect on how much they eat.

People eating with an overweight partner were more likely to serve themselves unhealthy foods and eat larger portions.

"This finding emphasizes the importance of pre-committing to meal choices before entering the restaurant," said lead author Mitsuru Shimizu, Assistant Professor of Psychology at Southern Illinois University, Edwardsville. "If you go into the restaurant knowing what you will order you're less likely to be negatively influenced by all of the things that nudge you to eat more."

To make their findings the researchers recruited 82 undergraduate college students to eat a spaghetti and salad lunch. An actress was hired to wear a prosthesis that caused her to appear about 50 pounds over her normal weight to eat with the participants.

In a series of four meals the actress served herself a healthy (more salad than spaghetti) and less healthy (more spaghetti than salad) while wearing the prosthesis and again without it.

The researchers found that when the actress appeared to be overweight the participants served and ate 31.6 percent more pasta, when she served herself the healthier meal of mostly salad the students ate 43.5 percent less salad.

The findings suggest people eat more when in contact with an overweight individual because they lose touch with their own health goals.

"Look up the menu beforehand and select a meal that suits your dietary goals. Or, if you're going to a buffet, pre-commit to selecting modest portions of healthy foods and with that goal in mind, those around you will have less of a negative influence over what you eat," Wansink said.

The study was published in a recent edition of the journal Appetite.

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