Special diets are followed by persons suffering from various disabilities or illnesses; diabetics are a well-known example. They are also followed, in the western world, by people who are ‘slimming’, and expressions such as ‘I’m on a diet’ commonly relate to that situation. The urge to control and influence both mental and physical states by means of food has been a constant in many cultures, whether in those organized religions which used fasting to attain heightened awareness or closer proximity to the deity, or among athletes such as sumo wrestlers, Roman gladiators, or English prize-fighters who wished to improve their strength. This manipulation of the act of eating has penetrated modern societies to such an extent that it seems inescapable. We seem to suffer from ‘difficulties with food’ more than any previous era (a process which began, perhaps, in the middle decades of the 19th century), although historians are quick to catch resonances of similar psychological states among the religious or the highly strung of earlier centuries. Some, however, even if not all, of our present condition must stem from our unparalleled condition of plenty or sufficiency, a happy circumstance that was denied many, if not most, of our ancestors. While earlier medical knowledge, particularly that founded on the humoral theories of classical Greece, had seen eating as a continuum, an ever-present influence on an individual’s health and well-being, modern ‘diets’ often have more specific ends. These are often the results of ‘food fads’ or erroneous medical theories. Some may have a short currency, in both the life of the nation and the life-cycle of the individual. Others, for example macrobiotic, vegetarian or fruitarian diets, have more general application and may be adopted for the whole life of the proponent. One consequence of our willingness to use food for purposes more varied than its obvious function of nourishment has been that food disorders, for example anorexia nervosa and bulimia, have become much more common.