The nutritional disturbance in anorexia nervosa almost invariably leads to striking physiological changes, which include amenorrhoea, bradycardia, hypotension and relative hypothermia with reversal of the usual diurnal temperature rhythm (Bliss and Branch, 1960; Mayer-Gross et al., 1960; Crisp and Roberts, 1962; Crisp, 1967a). Crisp (1965a, 1967a) has commented on the characteristic and excessive alertness, restlessness and insomnia displayed by anorexia nervosa patients, whom he regards as showing a specific type of malnutrition associated with carbohydrate starvation. Russell (1967) has also recently demonstrated that patients with this illness restrict especially their carbohydrate intake.