Good news: a McDonald’s ChickenMcNugget does contain chicken. But it’s not the main ingredient—not even close. According to Michael Pollan, author of The Omnivore’s Dilemma, a McNugget is made up of 38 ingredients, mostly chemicals and corn derivatives. In total, a McNugget is 56 percent corn products. But 0.02 percent is tertiary butylhydroquinone, a petroleum byproduct used as a preservative. TBHQ is actually butane, also known as lighter fluid.