Are you eating beef, or chicken, or corn?

Well, it is all the same. Kind of. According to a study,

The bulk of a fast-food hamburger from McDonald's, Burger King or Wendy's is made from cows that eat primarily corn, or so says a new study of the chemical composition of more than 480 fast-food burgers from across the nation.
And it isn't only cows that are eating corn. There is also evidence of a corn diet in chicken sandwiches, and even French fries get a good slathering of the fat that makes them so tasty from being fried in corn oil. .....
Eating a diet of meat from corn-fed animals hasn't been linked to any specific health effects in humans. But it has resulted in widespread environmental degradation, including drained water supplies, degraded soils, and reliance on fossil fuels for fertilizer, pesticides and farm machinery fuel, says preventive medicine physician Bob Lawrence, director of the Center for a Livable Future at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the study.