From the same point of view, however, we are not compelled to banish the carbohydrates entirely in those cases in which a certain degree of tolerance for them exists. Here we have to regard the sugar-consuming function only in so far as to see that it is exercised within the limits of its capacity. When, for example, a patient excretes no sugar while taking 50 grams of bread, and perhaps 10 grains of sugar while taking 100 grams of bread a day, we can then permit him, with a good conscience, to eat from 50 to 100 grams of bread. Experience has taught us that we need have no apprehen sion even if we exceed a little the limits of tolerance in these cases; it is only a glutting of the organism with carbohydrates that we must avoid.
But this question of overtaxing or sparing the sugar-destroying function is not the only one that calls for medical control and for a reduction in the amount of carbohydrates ingested. Another way in which harm results is that the patient, if left to himself, may easily take so much carbohydrate, which is of but little use to him, that the other and valuable nutrient substances, the proteids and fat, fall short; he eats and gorges, yet is not sufficiently nourished. The stomach is satisfied but the tissues are starved; the patient emaciates, loses strength, and becomes predisposed to secondary diseases. As soon, however, as his diet is regulated, the ingestion of sufficient quantities of albumin and fat is prescribed, and the carbohydrates are rele gated to a subordinate position, being allowed, as it were, as a reward for his conscientious adherence to the main diet; then the strength returns and he becomes once more, instead of a miserable, weakly invalid, a useful member of society.
From what has been said it may be seen that the reduction of carbohydrates signifies much more than a mere game of hide-and seek with the glycosuria. Through blind indulgence very material injury may be caused, but through a limitation of the ingestion of carbohydrates, regulated according to the necessities of the individual case, a very positive advantage may be gained.
d. Sirmilicance and Limitations of a Diet of Fat and Albumin.— As we have seen, the proteids and fat must constitute the main portion of the diabetic's diet, and in severe cases the question will arise whether in conjunction with other articles which contain no carbohydrates (certain vegetables, salt, water, alcoholic beverages, tea, and coffee), they shall not constitute the sole diet.
Experience has shown that there is not the least difficulty in a moderate restriction of the carbohydrates, such as is called for in mild cases. Almost every diabetic willingly submits to a permanent exclusion of sugar, sweetmeats, sweet wines, sweet fruits, the cereals, puddings, etc., from his diet if he is allowed a moderate quantity of
bread, potatoes, and certain fruits, and is not forced to be always on the lookout to see that a little flour more or less is not used in the preparation of his vegetables and sauces. The loss in nutritive mate rial through exclusion of the saccharine and starchy foods is easily replaced by a somewhat greater ingestion of flesh meat, eggs, fat smoked meats, such as ham, sausages, dried fish, and the like, so that the amount of available fuel corresponds to the daily needs and the patient's strength is maintained. This is the situation of many, indeed most, diabetics.
The difficulties begin when all the carbohydrates ingested, even the smallest amounts, appear again in the urine, or when a greater amount of carbohydrate is excreted than is taken into the system, and when the strictest abstinence does not prevent the occurrence of gly cosuria. These are the cases in which over-zealous physicians pre scribe an exclusive meat diet, allowing at the most a couple of eggs and a little green salad in addition. With such a diet, however, it is ab solutely impossible to introduce enough nutritive values to compensate for the loss of material and of energy in the organism. Even 1,000 grams of meat and six eggs furnish at the most but 1,500 calories; a deficit of 1,000 calories or more remains with its injurious con sequences. It is no wonder that patients under this diet excrete very little or no sugar, or that they at the same time grow weak and wretched and succumb finally to heart failure, coma, or any one of the multitudinous complications. Nevertheless the medical adviser has had the mournful satisfaction of seeing the diabetic suffer and die without any sugar in his urine ! Sensible physicians prescribe, therefore, large quantities of fat in addition to the proteids. Even in Germany, where for a long time, contrary to the practice in Latin countries, there was an unac countable opposition to the ingestion of any large amount of fat, its utility has gradually come to be recognized by all. The supplement ing of a strictly flesh diet with fat marks an essential advance in the therapy of diabetes, for the great importance of fat as a fuel makes it easy to maintain the calorie value of the food to the desired and necessary height. The fear that diabetics would not readily absorb large amounts of fat (MO grams and more) has been shown, except in the rarest instances, to be unfounded. The further fear that the large ingestion of fat, although it might indeed cover the calorie changes, would not suffice, in the absence of carbohydrates, to pre vent the breaking-down of the important albumin of the tissues has also been dispelled by the results of Weintraud's beautiful studies in metabolism.