When a well-nourished adult individual begins to fast completely, he begins to lose from 800 to 1000 g in weight daily (that is about 1 to 1 1/2 of his body weight). The daily losses remain more or less constant during the first eight days of fasting, then they become smaller. I will refrain from entering into a discussion of the conditions as they appear at this later period, because they are without significance in actual practice. I will only mention in passing that in continuous fasting death occurs when from 35 to 40% of the original weight has been sacrificed. The loss of weight in a fasting individual is more or less independent of the intake of water (by mouth, subcutaneously or by rectum). Generally speaking the demand for water is much smaller in an individual who is fasting than in a person who is taking even a small, although altogether inadequate, quantity of food. Persons who make an exhibition of continued fasting and who are allowed to take water in any desired quantity rarely drink more than 400 to 500 cc. a day. In individuals who are already very much reduced by chronic undernutrition and then suddenly undergo acute fasting, the absolute daily loss of weight is usually slighter, whereas the percentic losses of weight are just as high as those indicated above.

In chronic undernutrition the daily loss of weight varies greatly. Everything depends on the degree of undernutrition. Occasionally one witnesses even in continued undernutrition an arrest of the loss of weight, in fact, occasionally a transitory gain in weight. This phenomenon is dependent upon the water ingestion and the degree of water retention in the tissues. The retention of water may attain very considerable degrees before it becomes manifest by visible or tangible oedemas. Such a gain in weight may often give rise to false expectations in regard to improvement, unless the above conditions are carefully included in the calculation. A deceptive gain in weight or an arrest in the loss of weight is especially frequent in undernourished patients suffering from stomach or intestinal trouble, diabetes mellitus and insipidus, exophthalmic goitre and, of course, particularly in disorders of the heart and kidneys that are apt to produce oedematous accumulations. The total loss of weight may become very much greater in chronic undernutrition than ever in acute complete fasting. A reduction of the weight to 50 and 40% of the original weight is by no means a rare observation in cases of pulmonary tuberculosis, carcinoma of the oesophagus and of the stomach and diabetes mellitus. The greatest loss of weight that I have personally ever seen as the result of chronic undernutrition occurred in a woman of about the age of 40, weighing 120 kg. By voluntary undernutrition she reduced her weight within a year to 80 kg. She then became afflicted with pulmonary tuberculosis accompanied by serious loss of appetite. All attempts to adequately nourish her were in vain and, when she finally succumbed, six months after this time, she weighed only 46 kg; this represented a loss of 74 kg, that is, of 62% of her original weight, within a period of 18 months.