Savvy restaurant owners are always looking for ways to get us to order more food and drink. A fleeting daily specials board, subtle hints on the menu for "olives and bread to start," servers who wax lyrical about how great the crisp Sauvignon Blanc would go with that salmon, or the tried-and-tested favourite: "D'you want fries with that?"
One trick profit-watching hospitality bosses don't seem to have picked up on, however is the weight of their waitstaff.
Wait, what? Surely, the decision to order that extra side of onion rings has more to do with a diner's appetite (and wallet) than the body size of the person who serves them.
Well, not according to new research from Cornell University, which claims that being served by overweight front-of-house staff can impact how much food we order in restaurants.
Published in the Environment and Behaviour journal last month, the study analysed 497 interactions between randomly selected diners and waitstaff at more than 50 restaurants in the US, Spain, and France.
To qualify for the study, the restaurants needed to offer soup, salad, and alcoholic drinks alongside other choices. Large restaurant chains such as TGI Friday's were included but the majority of those used by the researchers were smaller, independent establishments.
The study identified the "fat" waiters and waitresses according to their body mass index (BMI), the system of measuring weight and height that puts those with a rating of 25 or above as overweight or obese.
The study found that customers were "four times as likely to order desserts" and 17.65 percent more likely to order alcoholic drinks from "heavy waitstaff with high body mass indexes compared to waitstaff with low body mass indexes."
The weight of customers themselves appeared to have no effect on their order, nor did the race or ethnicity of either customer or server.
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The reason? Study authors Tim Döring and Brian Wansink suggested that a heavy waiter or waitress "sets a social norm," making diners feel comfortable about ordering larger quantities of food. They added that "environmental settings have been recognised as crucial cues to a person's eating behaviour," and that lighting, music, or the attitude of servers can also impact customers' food choices.
The study's findings are similar to that of another Cornell University study from 2014, which found that eating with overweight people caused participants to consume more food. However Döring and Wansink point out that their research is the first to analyse diners' behaviour towards servers' weight within a full restaurant environment.
While that may be true, even the skinniest waiter in the world won't stop us from ordering the pulled pork sandwich with extra 'slaw and a double side of mozzarella fries. Sorry, science.