Whether green, fruity, frosty, or creamy, smoothies are one of the most popular go-to options for breakfast, snacks and post-workout recovery meals these days. But have you ever stopped to think about where the word smoothie comes from? We did some digging and here’s what we found out!

The concept of enjoying pureed fruit on a large, commercial scale actually kicked off in the 1920s, when Julius Freed, suffering from a sensitive stomach, discovered that by making fresh orange juice more frothy and less acidic he could finally enjoy the taste of citrus drinks. The result? Orange Julius, one of the longest-running fast food franchises, was born.

The rise of the smoothie from there was a perfect storm of several factors. First, the invention of safe home refrigeration in the 1930s meant you could start storing fresh fruit at home. Second, the invention of the blender in the 1940s led to affiliated recipe books that promoted as many uses for your blender as possible – including, in one “Recipes to Make Your Waring-Go-Round” cookbook, a dozen milk smoothies.

By the 1950s, milkshakes had really taken off and have remained an iconic symbol of teen culture during that era to this date.

But what made a smoothie different from a shake? Well, going back to the 1920s, smoothie was used to describe a suave, self-assured person, particularly when interacting with the opposite sex. This collegial term remained a part of youth culture and, by the 1960s, was applied to a variety of things that were considered slick, suave, or attractive – from ladies’ undergarments to smooth-writing ballpoint pens to automotive paint. Smoothie was actually part of the hippie vernacular at this point, used in these ways and more.

Hippie culture also led to a closer look at nutrition and health, as a pendulum shift from indulgent ’50s dining habits. Macrobiotic diets became popular, and health food stores began selling blended fruit juices to respond to this trend.

Enter Steven Kuhnau, another young man with digestive issues like Julius Freed. Lactose intolerant, Steven couldn’t drink milkshakes like his peers, so he created his own frozen treats by blending fruit, ice and other ingredients. He soon discovered these drinks tasted great, regulated his blood sugar, and helped with his food allergies in general. Excited with his concoctions and spotting a gap in the market, Steven decided to take his drinks to the masses.

Recognizing the importance of differentiating his frozen fruit drinks from shakes from a health and dietary restriction perspective, Steven applied the term smoothie mostly to appeal to hippies: a key demographic that was already tapped into the health benefits he was pushing. He knew the term was well-known among his audience, and thus his fast-food operation Smoothie King was born. And with 600 stores today, the brand that started the smoothie craze has also defined what makes a smoothie a smoothie.

While many smoothies today feature dairy ingredients, ultimately most people associate smoothies with nutrition and health benefits – all thanks to its origins in ’60s youth culture.