Another bite from "Animal Vegetable Miracle," Barbara Kingsolver's 2007 book:

According to Indian crop ecologist Vandana Shiva, humans have eaten some 80,000 plant species in our history. After recent precipitous changes, three-quarters of all human food now coms from just eight species, with the field quickly narrowing down to genetically modified corn, soy, and canola. If woodpeckers and pandas enjoy celebrity status on the endangered species list (dubious though such fame may be), food crops are the forgotten commoners. We're losing them as fast as we're losing rain forests. [pp. 49-50]

My first reaction was, canola? I didn't know about that one; I thought the big four were rice, wheat, soy, and corn. But I take the point about the vastly reduced plant diversity, which Kingsolver expands upon several pages later:

History has regularly proven it is drastically unwise for a population to depend on just a few varieties for the majority of its sustenance. The Irish once depended on a single potato, until the potato famine rewrote history and truncated many family trees. We now depend similarly on a few corn and soybean strains for the majority of calories (both animal and vegetable) eaten by U.S. citizens. Our addiction to just two crops has made us the fattest people who ever lived, dining just a few pathogens away from famine. [pg. 54]

My first reaction was, Wow, Kingsolver is really talented. Obesity surely is suicide on the installment plan, but I'd never connected that with the other edge of the sword, the potential pathogens that could take us from overweight to a quicker end by starvation.