The International Dietary Energy Consultative Group, sponsored by the World Health Organization (WHO), has done most of the research conducted in the field of adult malnutrition in the late 1980's. These studies were carried out mainly in populations suffering from chronic malnutrition, and led to the current WHO recommendations for the diagnosis and classification of adult malnutrition. Body Mass Index (BMI) is the gold standard to be used in adults, with the following cut-off points identified: 16.0, 17.0 and 18.5. The good correlation observed between BMI and Middle Upper Arm Circumference (MUAC) led to the determination of corresponding cut-off points. However, the very few field studies available in the literature are in favor of a lowering of the BMI cut-off points during nutritional emergencies. Several questions need to be answered through field research, mainly concerning the type of indicator best predicting the risk of death, and the type of indicator to be used in adolescents, pregnant women and older people.