We have not found that the acetone and diacetic acid output behaves in any constant manner during starvation; in some cases we have seen the acetone bodies disappear, in others we have seen them appear when they were not present before.
Their appearance is not necessarily a cause for alarm. The estimation of the ammonia in the urine is of some value in determining the amount of acidosis present, and this can readily be done by the simple chemical method given below. If the 24-hourly ammonia output reaches over 3 or 4 grams, it means that there is a good deal of acidosis--anything below this is not remarkable. More exact methods of determining the amount of acidosis are the determination of the ratio between the total urinary nitrogen and the ammonia, the quantitation of the acetone, diacetic acid and oxy-butyric acid excreted, and the carbon dioxide tension of the alveolar air. These are rather complicated for average clinical use, however.
When the patient is sugar-free he is put upon a diet of so-called "5% vegetables," _i.e._ vegetables containing approximately 5% carbohydrate. It is best to boil these vegetables three times, with changes of water. In this way their carbohydrate content is reduced, probably about one-half. A moderate amount of fat, in the form of butter, can be given with this vegetable diet if desired. The amount of carbohydrate in these green vegetables is not at all inconsiderable, and if the patient eats as much as he desires, it is possible for him to have an intake of 25 or 30 grams, which is altogether too much; the first day after starvation the carbohydrate intake should not be over 15 grams. Tables No. 1 and No. 2 represent these vegetable diets. The patient is usually kept on diet 1 or 2 for one day, or if the case is a particularly severe one, for two days. The day after the vegetable day, the protein and fat are raised, the carbohydrate being left at the same figure (diets 2, 3 and 4). No absolute rule can be laid down for the length of time for a patient to remain on one diet, but in general we do not give the very low diets such as 2, 3 and 4, for more than a day or two at a time. _The diet should be raised very gradually_, and it is not well to raise the protein and carbohydrate at the same time, for it is important to know which of the two is causing the more trouble. The protein intake may perhaps be raised more rapidly than the carbohydrate, but an excess of protein is very important in causing glycosuria, and for this reason the protein intake must be watched as carefully as the carbohydrate. With adults, it is advisable to give about 1 gram of protein per kilogram of body weight, if possible; with children 1.5 to 2 grams. It will be noticed that the diets which follow contain rather small amounts of fat, a good deal less than is usually given to diabetics. There are two reasons for this: In the first place, _we do not want our diabetics, our adults, at any rate, to gain weight; and in the second place acidosis is much easier to get rid of if the fat intake is kept low_. If the fat values given in the diets are found too low for any individual case, fat can very easily be added in the form of butter, cream or bacon. Most adults do well on about 30 calories per kilogram of body weight; children of four years need 75 calories per kilogram, children of eight years need 60, and children of twelve years need 50.