Corn is in freakin’ everything. If you drink soda, you are consuming corn. If you eat animals, there is probably corn – a lot of corn – in their biomass. There’s most likely corn in your bread, even if it’s whole wheat. There is certainly corn inside 22-year-old Boston buds Curt Ellis and Ian Cheney, who discover after an elemental analysis of hair samples that the predominant carbon in their bodies originates from corn. Conducting the test is Steve Macko of the University of Virginia, who adds, “I’m not talking about corn on the cob, sweet corn. I’m talking about the corn that’s being used as a material going into the foods we use ubiquitously.” This mystery corn has a name – Yellow dent No. 2 – and it has overtaken Iowa, where Ellis and Cheney go to learn about corn by farming a 1-acre plot of it. (They have a city-boy concept of an acre and are chagrined to plant their parcel in 18 minutes.) Their agenda is straightforward – “For the first time in American history, our generation was at risk of having a shorter life span than our parents, and it was because of what we ate” – but largely the film is defined by a playful curiosity. Ellis and Cheney discover the "farm program," which pays them $28, and they follow the rabbit hole of farm subsidies all the way to former Secretary of Agriculture Earl Butz, who, though nearly a century old, staunchly defends the “philosophy of expansion” that crowned cheap corn king in 1973. Bred for more starch and less germ – yes, it is designed to be less nutritious – yellow-dent corn also feeds America’s livestock, so Ellis and Cheney visit the actual exposed, working stomach of a cow being studied at Iowa State University on an all-grain diet. It’s not pretty. Neither is the economic reshaping of the heartland, a process Ellis and Cheney depict whimsically but clearly with stop-motion animations of a vintage Fisher-Price Family Farm evolving into a mass operation. Yet the point is best made by a farmer’s disgust with “the poorest quality crop the world has ever seen.” The film’s light hand, appealing style, and simple exposition make it an eminently watchable inquiry into the politics of food and public health, accessible to the documentary-shy and wildly appropriate for older kids, who may further respond to its generational emphasis.