With 81.6 billion acres of the stuff blanketing the heartland, corn is America’s largest crop. When you think of corn, you think of benign, happy imagery: backyard barbecues, sun-weathered farmers in dusty overalls, green fields gently swaying in a summer breeze.

Ask the average American how much corn he or she actually eats, however, and you’re apt to get some radically off-base answers. Outside of movie popcorn, the aforementioned summer barbecues, cornflakes, Fritos and the intermittent salsa or tamale, corn isn’t a major part of our daily diets, right?

Wrong, shout holistic nutrition buffs, natural foods aficionados and anyone who’s read their Michael Pollan. As filmmakers Ian Cheney and Curt Ellis so harrowingly documented in King Corn (out on DVD now), the enduring golden symbol of the American heartland is in fact an insidious component in almost everything we put in our mouths, a secret ingredient that takes many forms and hides behind many names (most of them unpronounceable). Responding to Cheney and Ellis’s King Corn Challenge, writer Katherine Pryor attempted to cut any and all corn-based products out of her diet for three days and found herself... well... really hungry.

Sunday, 10 a.m.

I have accepted the King Corn Challenge.

For the next 72 hours, I will eat nothing with corn products or corn derivatives, which pretty much excludes all the mysterious multisyllabic ingredients on the back of most processed foods. It also excludes all those “acids”: ascorbic, citric, lactic, malic or otherwise.

Coffee is thankfully still on the list, and I brew my morning espresso with confidence. Then I reach for the soymilk (cow milk is out, as the cows probably ate corn) and realize it contains vanilla, which CornAllergens.com warns me often contains corn. Okay — I’ll start the challenge right after this latte.

In The Omnivore’s Dilemma, Michael Pollan pointed out the ubiquity of corn in the American diet. A combination of farm subsidies, hyper-productivity brought on by agribusiness technologies, and plain poor planning has left us with more corn than we know what to do with. We feed a good chunk of it to livestock, but that still leaves us with mountains of the stuff. We turn it into skincare products, food thickeners and preservatives. Much of it becomes high fructose corn syrup — a product that has found its way into most sodas, juices, cookies and crackers on supermarket shelves. Recently, high fructose corn syrup has been popping up with alarming regularity in articles on obesity and diabetes. This abundance of corn could be partially responsible for many of the health issues that our country is facing.

Breakfast is tougher than I thought. The Organic Valley eggs are out, as the chickens surely ate corn feed (albeit organic). My tortillas contain baking powder, and the unbleached, preservative-free, whole wheat bread I purchased specifically for this challenge contains polenta. Oops.

I reach for an apple.

I begin to worry about lunch.

I buy a simple loaf of whole wheat bread from the farmers’ market and a beautiful queso fresco from a grass-fed dairy company. No one has grass-fed milk at the market, as it is almost calving season. I stock up on vegetables and apples and enjoy a hot curried carrot soup sweetened with coconut milk.

Dinner is a vegetable stir-fry over rice pilaf, and dessert is a juicy mango. This isn’t so bad, really.