Up-selling is a little trickier with cashiers, who might forget or feel uncomfortable trying to push more food on customers. With kiosks, that isn’t a problem. Customers may also be willing to buy additional food because the privacy of the transaction means no one is judging them, Rosenberg said.

Suggestions can be customized for particular orders, too. Someone who buys a burger might be offered fries, or a person who orders a salad could be offered a yogurt.