The larger your friends the larger your appetite

'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.' Credit: Daniel Miller

Have you ever ordered more food at a restaurant than you intended? There are elements of dining rooms that actually prime you to eat more food. One such element is the weight of those dining with or near you. This new Cornell University study found that the body type of your dining partner, or that of those dining nearby, may actually influence how much you serve yourself and how much you eat!

03 oct 2014--The study investigated the impact the presence of an overweight diner on healthy and unhealthy food choices and found you are more likely to serve and eat more unhealthy foods and less healthy foods when eating with or near someone who is overweight. These findings support a theory that when eating with or near an overweight person, you may be less likely to adhere to your own health goals. "This finding emphasizes the importance of pre-committing to meal choices before entering the restaurant," says 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."

The study published in Appetite was co-authored by Katie Johnson of Mayo Medical School and Brian Wansink, PhD director of Cornell University's Food and Brand Lab and author of the new book: Slim by Design: Mindless Eating Solutions for Everyday Life. The researchers recruited 82 undergraduate college students to eat a spaghetti and salad lunch. They also enlisted an actress to wear a prosthesis that added 50 pounds to her normally average weight. Each of the 82 participants was randomly assigned to one of four scenarios: the actress served herself healthfully (more salad and less pasta) while wearing the prosthesis, she served herself the same healthy meal without the prosthesis, she served herself less healthfully (more pasta and less salad) while wearing the prosthesis, or she served herself the same less healthy meal without the prosthesis. Participants in each scenario viewed the actress serving herself and then served themselves pasta and salad. Researchers found that when the actress wore the prosthesis, and appeared overweight, the other participants served and ate 31.6% more pasta regardless of whether she served herself mostly pasta or mostly salad. When she wore the prosthesis and served herself more salad, the other participants actually served and ate 43.5% less salad.

These findings demonstrate that people may serve and eat larger portions of unhealthy foods and smaller portions of healthy foods when eating with an overweight person because they are less in tune with their own health goals. Luckily, this phenomenon is easy to avoid by simply assessing your level of hunger before going to the restaurant and planning your meal accordingly. Wansink recommends, "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."

More information: Shimizu, Mitsuru, Katie Johnson, and Brian Wansink. (2014). In good company. The effect of an eating companion's appearance on food intake. Appetite, 8, 263-268. DOI: 10.1016/j.appet.2014.09.004