Food fads come and go. At present a procession of so-called 'super foods' are dangled in front of us, promising, if not eternal life , then eternal "wellness". We have kale, micro greens, coconut water, quinoa and the implication that anything containing gluten will lead to an early grave. This set former NZ Dairy Board PR guru Neville Martin ruminating on the vagaries of food fashion, and he was prompted to pen a memoir on growing kohlrabi.