Jell-O, the 104-year-old treat that's currently sitting in over 72 percent of American kitchens, consists of four main ingredients: gelatin, water, artificial sweetener, and food coloring. Gelatin is the stuff that lends Jell-O its weird, not-quite-liquid, but-also-not-very-solid structure.

Gelatin is made up of a protein called collagen that's found in cow and pig hides, hooves, bones, and connective tissue. To make Jell-O, this stuff is boiled down, chemicals are added, and then the collagen is extracted. So Jell-O is pretty much off limits for a vegetarian diet. According to the official Jell-O web site, every four seconds a box of Jell-O gelatin is sold in the United States.