Eat real food. This is the advice of a thousand health advocates at a thousand typewriters in a thousand books. The problem is definitional: What is real food?

A thinking person can weed out the obvious imposters created by corporations who aren’t overwhelmingly concerned about public health or good: froot flavor, cheezy goodness. But for the past few years, food has been reimagined by our fin-de-millennium heroes—technology entrepreneurs—who we assume are creating more products that will make the world a better place.

In the past five years or so, Silicon Valley, through its individual billionaires and hedge funds, has pumped more than a billion dollars into food technology ($250 million in the past month alone), including creating high-end food substitutes. The