We are no longer like our ancestors. We no longer depend on our skills as foragers, gatherers, scavengers, hunters and fishers for food. We are only part-time food raisers at best. . . Our biology, on the other hand, has changed far less. Now there is a mismatch between who we are and what we eat. And it is in the gap created by this mismatch that chronic diseases. . . can take root. John Potter, an award-winning public health researcher, examines the latest research on what causes cancer and other chronic diseases. What is scientists current understanding of the balance between diet, genes and plain bad luck, and how is the balance shifting? He explores how our adaptation to the diets of our ancestors can be linked to the diseases we experience in the present and explains what the evidence says we can do about it.