Many fast-food items from McDonald’s, Burger King and Wendy’s contain a large quantity of corn.

Corn is the main ingredient in all chicken and nearly all beef sampled at the three aforementioned fast food restaurants on the mainland, according to Hope Jahren a geobiologist and professor at the University of Hawaii.

Study authors A. Hope Jahren and Rebecca Kraft looked at 480 fast food products to determine how corn, which is regularly used in feedlots to fatten cows up before slaughter, is employed in the production of fast food. After purchasing food over a two-year period from several eateries in Los Angeles, San Francisco, Detroit, Denver, Boston and Baltimore, they freeze dried the items and send them to a laboratory in order to be analyzed.

Thanks to a technique that identifies carbon and nitrogen isotopes in meat, the research team learned the animals' diets, as well as the conditions in which they were raised. Researchers found that the cattle and poultry were especially fed corn, an ingredient that makes them as fat as possible in a short period of time. What’s more, the animals were found to be raised in harsh confinement.

As stated by the United States Department of Agriculture, the country produced 48.7 billion pounds of commercial red meat in 2007, 8.1 billion chickens and 90.6 billion eggs. Jahren’s and Kraft’s report, published in this week's issue of the Proceedings of the National Academy of Sciences, disclosed that U.S. residents spend annually over $100 on fast food products.

"In my opinion, we're experiencing a food awakening in this country," said Cynthia Sass, a nutritionist in New York City. A growing number of consumers “want to know where their food comes from and how it's grown. Consumers are starting to think about the traceability of food and connect the dots in the big picture of food production, particularly in terms of how it impacts the environment, our health and the health of our children," she said.