Growing up, Steve Kuhnau couldn't enjoy ice-cream sundaes and peanut-butter sandwiches because of his food allergies. In a quest for a healthy alternative, Kuhnau began mixing fresh fruits and nondairy proteins, innovating an entirely new concoction—the smoothie. He and his wife began selling blended treats out of their vitamin shop in 1973, and in the decades since, hundreds of Smoothie King franchises have opened across the country.

These days, the menu brims with more than 80 smoothie flavors, which range from Slim-N-Trim Chocolate to Banana Berry Treat. Low-cal, high-protein, and vitamin-fortified varieties accommodate dietary needs and can be customized with enhancers such as probiotics and antioxidants. Sharon Heausler, who owns the Bandera Road location, packs her shop with protein bars and nutritional supplements and dispenses gold stars to well-behaved patrons.