Your Sunday reading: How Vegetable Oils Replaced Animal Fats in the American Diet from The Atlantic
Oddly enough, the company to thank for the fact that America now eats so much vegetable oil has never produced much in the way of food. Thanks to Procter & Gamble the United States boosted the production of a waste product of cotton farming, cottonseed oil. To ensure a steady, cheap supply for soap production the company formed a subsidiary in 1902 called Buckeye Cotton Oil Co. Before processing, cottonseed oil is cloudy red and bitter to the taste because of a natural phytochemical called gossypol (it's used today in China as male birth control) and is toxic to most animals, causing dangerous spikes in the body's potassium levels, organ damage, and paralysis.
An issue of Popular Science from the era sums up the evolution of cottonseed nicely: "What was garbage in 1860 was fertilizer in 1870, cattle feed in 1880, and table food and many things else in 1890." But it entered our food supply slowly. It wasn't until a new food-processing invention of hydrogenation that cottonseed oil found its way into the kitchens of America's restaurants and homes.