Weird wheat? Modern wheat could be making you hungry, fat, and sick.

Take everything you've heard about whole wheat and throw it out the window. It's not a health food, it's making you fat, and your digestive tract hates you for eating it, according to the author of the New York Times best-selling book, Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health (Rodale, 2011).

So how—and when—did this ancient grain become such a serious health threat? Author and preventive cardiologist William Davis, MD, says it's when big agriculture stepped in decades ago to develop a higher-yielding crop. Today's "wheat," he says, isn't even wheat, thanks to some of the most intense crossbreeding efforts ever seen. "The wheat products sold to you today are nothing like the wheat products of our grandmother's age, very different from the wheat of the early 20th Century, and completely transformed from the wheat of the Bible and earlier," he says.

Plant breeders changed wheat in dramatic ways. Once more than four feet tall, modern wheat—the type grown in 99 percent of wheat fields around the world—is now a stocky two-foot-tall plant with an unusually large seed head. Dr. Davis says accomplishing this involved crossing wheat with non-wheat grasses to introduce altogether new genes, using techniques like irradiation of wheat seeds and embryos with chemicals, gamma rays, and high-dose X-rays to induce mutations.

Clearfield Wheat, grown on nearly 1 million acres in the Pacific Northwest and sold by BASF Corporation—the world's largest chemical manufacturer—was created in a geneticist's lab by exposing wheat seeds and embryos to the mutation-inducing industrial toxin sodium azide, a substance poisonous to humans and known for exploding when mishandled, says Dr. Davis. This hybridized wheat doesn't survive in the wild, and most farmers rely on toxic chemical fertilizers and pesticides to keep the crops alive. (It's important to note, however, that the intensive breeding efforts that have so dramatically transformed wheat should not to be confused with genetic engineering of food, or GMOs. This type of technology has its own set of problems, though.)

So what does all of this plant science have to do with what's ailing us? Intense crossbreeding created significant changes in the amino acids in wheat's glutenproteins, a potential cause for the 400 percent increase in celiac disease over the past 40 years. Wheat's gliadin protein has also undergone changes, with what appears to be a dire consequence. "Compared to its pre-1960s predecessor, modern gliadin is a potent appetite stimulant," explains Dr. Davis. "The new gliadin proteins may also account for the explosion in inflammatory diseases we're seeing."