Your Server's Wide Waistline May Steer You Towards DessertDiners who were served by a waiter with higher BMIs were more likely to end their meals with a sweet treat, according to study.

The meal is done. You are so full, it's borderline uncomfortable. And yet, "anyone interested in dessert?" entices nonetheless.

Your ability to resist this sugary siren call is influenced by a variety of obvious factors: the available options, the tightness of your pants, your mood and willpower reserve. But other, sneakier variables can also play a role.

Like the size of your waiter.

That's the takeaway from a recent study in the journal ofEnvironment and Behavior, anyway. Researchers observed 497 diners ordering in fast casual restaurants across the country and found that when they were served by a heavier waiter, they were 17 percent more likely to order alcohol and more than four times as likely to order dessert.

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For the record, the study defines "heavy" as a BMI of more than 25, while "slim" is a BMI of less than or equal to a BMI of 25.

The study, the authors stress, is observational, meaning they are unable "to draw clear causalities." To collect the information, the researchers essentially lurked in restaurants across America, and estimated diners' and waiters' weight, body type (from a chart of 18 options), gender, ethnicity, food and drink order and, somewhat bizarrely, type of clothing (options included loose or tight and dressy, casual or sloppy -- although the metric was ultimately not included as part of the analysis).

Slimmer diners' decision to get dessert was particularly influenced by their waiters' size: when the server was slim, they ordered dessert 4 percent of the time compared to 14 percent when their server was heavy. For heavy diners -- who were more than four times as likely to get dessert in the first place -- this increase was more subtle but still significant, rising from 16 percent to 21 percent.

While previous studies have found that environmental cues -- everything from lighting, plate size andutensils-- has an impact on what and how much we eat, the researchers suspect something more specific is at play in this case. Again, the study doesn't prove causality, but the authors hypothesize that "diners may order and eat more food and beverages in the presence of a heavy person because a heavy person sets a social norm."

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In a potentially related phenomenon, sit-down diners who can order from a touchscreen without interacting with a waiter at restaurants such as Applebee's, The Olive Garden and Chili's have reported an increase in dessert orders. Ziosk, the company that makes these tablets, claims that tablet installationboosts dessert sales by 30 percent.

Uno's manager Andy Skylartold NPR's Planet Moneyhe attributes the increase to societal pressure: we feel judged by our waiter for ordering dessert after eating a big, cheesy meal. But replace that waiter with a faceless computer? Suddenly that feeling of judgement goes away.

The same may be true when you're ordering dessert from a waiter who looks like he or she also indulges in the good stuff. Or, as lead author Tim Doering put it in the study's corresponding press release, "A fun, happy, heavy waiter, might lead a diner to say "What the heck' and to cut loose a little."

As the study notes, this means restaurants may benefit from hiring heavier servers:

"There have been several lawsuits within the past couple of years regarding weight discrimination of employees in bars and franchise restaurants," the authors write. "This research shows that heavy wait staff does not have to be a liability for business. If anything, heavy wait staff might increase sales."

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