Do your ears burn whenever you eat hot chile peppers? Does your face immediately flush when you drink alcohol? Does your stomach groan if you are exposed to raw milk or green fava beans? If so, you are probably among the one-third of the world's human population that is sensitive to certain foods due to your genes' interactions with them. Formerly misunderstood as "genetic disorders," many of these sensitivities are now considered to be adaptations that our ancestors evolved in response to the dietary choices and diseases they faced over millennia in particular landscapes. They are liabilities only when we are "out of place," on globalized diets depleted of certain chemicals that triggered adaptive responses in our ancestors. In Why Some Like It Hot, an award-winning natural historian takes us on a culinary odyssey to solve the puzzles posed by "the ghosts of evolution" hidden within every culture and its traditional cuisine. As we travel with Nabhan from Java and Bali to Crete and Sardinia, to Hawaii and Mexico, we learn how various ethnic cuisines formerly protected their traditional consumers from both infectious and nutrition-related diseases. We also bear witness to the tragic consequences of the loss of traditional foods, from adult-onset diabetes running rampant among 100 million indigenous peoples to the historic rise in heart disease among individuals of northern European descent. In this, the most insightful and far-reaching book of his career, Nabhan offers us a view of genes, diets, ethnicity, and place that will forever change the way we understand human health and cultural diversity. This book marks the dawning of evolutionary gastronomy in a way that may save and enrich millions of lives.