If a food-deprivation stunt fell during the biggest feasting time of the year, would anyone care?

Curt Ellis and Ian Cheney, makers of the documentary

King Corn

, gave it a shot last month. The former Yale classmates, 28 and 27, became hyper-aware of the ways corn played a part in their fast-food/processed-food eating regimen, as well as in the nation's agribusiness.

But had

the movie changed the way they eat? Not so much, they admitted. Both ate more grass-fed beef and less beef produced from corn feedlots. But they slipped back into their old high-fructose-corn-syrup-filled habits.

As it happens, no one needs to be eating a lot of corn and its derivatives. "It is a terrible food in itself," says University of Virginia organic geochemist Stephen Macko. "It doesn't have a lot of essential amino acids or good levels of protein."

So Ellis and Cheney challenged each other with a corn-free month. The proof would be in the retesting of their carbon isotope composition, done back in Macko's lab.

Ellis and Cheney spent the month hungry. Both consumed "lower on the food chain," eating unprocessed fruits and vegetables.

"I ate sauteed spinach for breakfast, a lot of salads for lunch and grass-fed lamb or halibut for dinner," Ellis said. "I baked my own bread. It was hard going without milk or eggs, or cream in my coffee."

Cheney checked labels, ate "more oatmeal than I've ever had in my whole life" and devoured an occasional bag of potato chips fried in cottonseed oil.

At the end of the month they received Macko's results: The amounts of carbon with corn markers had dropped for both. Ellis, down to 39 percent. Cheney, 44 percent.

Now Ellis is "trying hard to not eat too much high-fructose corn syrup. I make an exception for ketchup, though."