I was surprised watching the beginning of "The Seven Year Itch" from 1955 to see soybean burgers and a vegetarian restaurant!
After work, Sherman resists giving in to any form of temptation, and goes to a vegetarian restaurant on 3rd Avenue for dinner: "Health, that's the stuff. The human body is a very delicate machine, a precision instrument. You can't run it on martinis and Hungarian goulash especially in this hot weather." The restaurant displays its typical offerings, Spinach Loaf, Yogurt, and Dandelion Salad, but Richard has ordered the #7 Special: Soybean Hamburger with french-fried soybeans, soybean sherbert, peppermint tea, and a drink to start - a sauerkraut juice on the rocks.
Even more surprising happens shortly thereafter, when Sherman is drinking a bottle of soda at home and starts to read off the ingredients and mentions corn syrup! So much for the notion that sugar was the only sweetener in pop back in the day. Apparently, corn syrup has been around a long time in soda and it's only lately that it's getting a bad rap.