Butter is milk fat that is rapidly converted by the body into people fat. Butter had been around for 4000 years with no real competition until 1869, when French chemist Hippolyte Mège-Mouriès horrified American dairy farmers with his patented, lower-priced spread known as margarine.
Frantic political lobbying and prohibitive licensing fees ensued. Margarine was blamed for destroying the moral order and threatening the American way of life. Some states banned it outright. When margarine makers added yellow coloring to their naturally grey product, butter makers cried foul, claiming this was a sneaky ploy to deceive the public (never mind that the familiar yellow of butter was itself the result of artificial coloring).
Margarine-makers countered by supplying a separate capsule of yellow coloring to be added by the consumer. In Wisconsin, the heart of America’s dairy land, even this was a crime punishable by heavy fines. It wasn’t until 1967 that this margarine-coloring law was finally repealed.