For the first time in history, too much food is making us sick. It's all too apparent that the Modern American Diet (MAD) is expanding our waistlines; what's less obvious is that it's starving and shrinking our brains. Rates of obesity and depression have recently doubled, and while these epidemics are closely linked, few experts are connecting the dots for the average American.

Using the latest data from the rapidly changing fields of neuroscience and nutrition, The Happiness Diet shows that over the past several generations small, seemingly insignificant changes to our diet...