Anorexia nervosa: a model of malnutrition.

Anorexia nervosa is a typical kind of malnutrition resulting from chronic s tarvation. The malnutrition is related to a severe eating disorder (fear of eating and becoming fat) causing reduction of food intake. The large major ity of the patients are women (95%). There are two types of anorexia nervos a with different prognosis and treatment: the restricting type and the "pur ging" type (with or without bulimia), In this kind of malnutrition, plasma nutritional markers are normal. The decrease in energy intake induces an ad aptative decrease in energy expenditure, Body weight loss is related to a l oss in fat free mass and in fat mass, although there is an increase in extr acellular water. Below a body mass index of 15 kg/(m)(2), sodium and mater retention require prescription of a low sodium diet. Several factors of res istance are operating in this disease, acting against body weight gain: met abolic wasting of energy expenditure (futile cycles), fear-related energy e xpenditure, dissimulations, Recovery is still long and difficult to obtain and requires a combined nutritional and psychotherapeutic approach.