Fast food isn't some newfangled invention. It's been around for centuries, albeit in different forms.

Ancient Roman fast-food joints were called "thermopolia."

These restaurants had a bad reputation, but they provided fast and cheap meals to the poor of ancient Rome.

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Fast food has been around for quite some time.

Even ancient people hankered for a spot where they could swing by and grab a hot meal. For the ancient Romans, that's where thermopolia came in. The word translates to "places where hot drinks are sold."

Historian and "Food and Drink in Antiquity: A Sourcebook: Readings from the Graeco-Roman World" author John Donahue wrote that these restaurants hawked the "ancient equivalent of modern fast food."

Read more: The secret history of McDonald's Filet-O-Fish, which was almost killed from the menu before becoming one of the chain's staple sandwiches

Most of the restaurants operated out of small rooms fronted by large countertops. Some spots also featured cramped dining areas, but the primary function of the thermopolium (that's the singular version of "thermapolia," if you were wondering) was to sell take-out food.

Many Romans didn't have the time or means to prepare meals at home and came to rely on these ubiquitous eateries.

Take a look at these ancient fast-food joints: