Sauder study reveals an overweight server can make you eat more


Recently, the media has reported that Canadians are gaining more weight, faster than people in the majority of other high-income western world countries. But we aren’t the only ones tipping the scales. In fact, rising obesity is a global problem, with well-off western countries leading the way. Since 1980, the number of obese adults worldwide has doubled and in 2008 more than half a billion adults shared this problem.

Given everything that science has revealed about the numerous health risk factors associated with obesity—not to mention the enormous financial burden that obesity places on healthcare systems—what drives some of the world’s wealthiest and best-educated populations to continue to over-consume?

A new study co-written by Sauder School of Business marketing professor Darren Dahl suggests that societal weight gain may be a slippery slope and that being fat could be making us fatter.

“A subtle social influence cue can have a significant impact on our consumption choices,” says Sauder marketing professor Darren Dahl. The researcher’s paper, “Might an overweight waitress make you eat more? How the body type of others is sufficient to alter our food consumption,” recently published in the Journal of Consumer Psychology shows that people’s food choices and the amount they eat is influenced by the weight of those around us.

“We show that obesity in our society has unintended effects with respect to social influence – specifically for a vulnerable population,” explains Dahl. “We speculate that dieters identify with an obese server in their willingness to take food recommendations and increase their food consumption when influenced by a heavier server.”

The research shows how the body type of others around us may be sufficient to alter our consumption choices. It suggests that being aware of how situational influences impact our choices is important for ultimately correcting them and making healthier lifestyle decisions to achieve or maintain a healthy body weight.

The study focused on only women, as past research has shown that females are more sensitive to social comparisons regarding body type. The study was conducted with a server whose body type was manipulated with an obesity prosthesis so that she could play both the ‘thin’ and ‘obese’ servers in the study.

The first experiment, in which 80 female students were invited to participate in a study on “taste-testing,” measured the food consumption quantity of non-dieting and dieting female students when served by the thin and obese server. In this experiment, the server presented the participants with two bite-size snacks – chocolate chip cookies or sugar-glazed rice cakes.

Dieters ate an average of approximately seven and a half snacks when served by an obese server versus approximately five snacks when served by a thin server. Conversely, non-dieters ate an average of approximately five snacks when served by an obese server versus approximately seven and a half snacks when served by a thin server. Non-dieters assimilated towards the thin server and contrasting away from the obese server, while dieters showed the opposite effect.

The second experiment showed that the types of foods dieters choose in addition to the quantity consumed, can be altered solely by a server’s body type. Sixty-eight female students, all of whom indicated that they were currently dieting or had been in the past year, participated in this experiment. In this experiment, the server, whose body type was also manipulated as in the first experiment, presented these participants with two snack choices – a healthy one, carrots, and an unhealthy one, cookies.

When cookies were recommended, dieters chose cookies more often when the server was heavy than when she was thin – 73 per cent versus 53 per cent. But when carrots were recommended, they selected cookies with a greater frequency when the server was thin than when she was heavy – 53 per cent versus 79 per cent. Dieters were more persuaded by an obese server than a thin one, choosing both the healthy and unhealthy relatively more often when she recommended it.