Waste of food material occurs both oeconomically and physiologically. Not to mention the oeconomic losses in preparing and transporting foods from the original source to the retail market, and the financial waste in using, often through ignorance, expensive food stuffs of less protein or caloric value than cheaper ones; the trimming and paring of foods in the kitchen and at the table, and the serving of larger portions than are eaten, involved a considerable waste, which must be considered in all cases in which computation of the nutrients is necessary. On the average the waste of digestible and assimilable foods in the kitchen and dining room, amounts to at least 10% and often 50%. Gross waste is often due to lack of care in the cooking and serving of food. Excepting in the commercial sense, the removal *of fat, skin, seed pods, husks, cores, and other indigestible parts of crude foodstuffs, can not be considered as waste.

Physiologic waste is due to two main factors - excessive ingestion of one or more kinds of organic nutriment and the swallowing of food imperfectly comminuted. Any vegetable food swallowed in its seed coats, as peas, beans, corn, huckleberries, etc., largely escapes digestion. So, too, starchy vegetables, meats, eggs, etc., swallowed without thorough mastication, are wasted to a large degree. Even milk drunk like water, so as to form large curds, may be passed unchanged. Alimentary saprophy-tosis, though possibly aiding slightly in the digestion of certain food materials, especially by dissolving cellulose inclosing starch, always causes some loss and often considerable. The efficiency of the various digestive secretions, also has an obvious influence on the amount of alimentary waste.

Granting that digestion is normal, mastication well performed and intestinal saprophytosis within normal limits, Atkinson estimates the utilization of some of the staple food stuffs, as follows:

Obviously, considerable variations will be found, even in the same individual. Leo Breisacher, for instance, found the percentage of albumin lost 2.9%, 4.9 % and 3.7%, after milk and cheese, and 6.5%, 7%, 7.7% and 12%, after milk alone, in respective experiments.

Percentage Of Unabsorbed Albumin, Leo Breisacher

Corn meal.......15..5%

Rice............20.4%

Peas, cooked soft .17.5% Peas, cooked soft 27.8%

Peas and bread. .12.2%

Rye bread.......22.2%

Black bread......32. %

Lentils..........40. %

Wheat bread.. .19.0% Wheat bread.. .18.7%

Potatoes.......32.2%

Potatoes, lentils and bread. . . 53.5%

Percentage Of Unabsorbed Fat, Leo Breisacher

During a fast, a trifle over 1 gram of fat is lost daily in the stools. When 25 - 40 grams are ingested the loss is 10 - 15% or about 4 grams. When 100 grams are taken, the gross loss is about the same, the percentage being obviously reduced, and, indeed, the actual loss may be as low as 1.25%. This paradox is undoubtedly due to the fact that, when very little fat is taken, it is mainly in the form of beef and mutton or other meat fat, and in that of vegetables in which it is imbedded in cellulose, and has a high melting point. Moreover, the less the ingestion of fat, the greater proportionately does the inevitable loss of about a gram a day become. When the fat is increased beyond 150 grams, the loss becomes very great, 20% or more, especially when oils are given that have a direct laxative action.

On a coarse vegetable diet, the waste of all kinds of nourishment becomes progressively greater, also on account of the laxative effect. In general, the finer the sub-division of the food stuff, the greater the utilization of nourishment. For instance, whole wheat bread - except for decortication - yields only 69% of its protein and 92% of its carbohydrate, as compared with nearly 81% and nearly 100% respectively, for bread made of fine, bolted flour. This fact alone illustrates the lack of sense of the diatribes against fine flours. Potatoes ag ordinarily cooked and masticated, yield 70% of their protein and 92% of their carbohydrate, whereas by serving in the form of a puree, these percentages are increased to 80 and nearly 100, respectively. The coarser vegetables, such as cabbage, carrots, beets, etc., yield at best 60 - 80% of their protein and 80 - 85% of their carbohydrate. If not cooked tender and not well masticated, used abundantly and continuously, the waste may exceed the utilization.

Rubner estimates that on ail ordinary mixed diet the waste of nutriment amounts to about 8% of the total calories, under the best physiologic conditions.

For practical purposes, therefore, 200 or 300 calories of the standard ration may be considered to be wasted by failure of digestion. However, as the requirements are usually stated in terms of ingested food required, and as a variation of this amount is not of importance, the physiologic waste of nutriment need not ordinarily be considered. However, variations in waste explain such discrepancies as that two persons of the same size and exercising to the same degree, require different amounts of food to maintain weight.

Normal faeces - amounting to somewhere about 100 grams - contain about 20% of fat and about 7% of albumin obtained by multiplying the nitrogen by 6.25. But the nitrogen is largely excrementitious, that is to say, waste rather than wasted material. Practically no carbohydrate - except cellulose - is present, but, on the other hand, considerable theoretically available carbohydrate, and a less but still appreciable amount of protein and fat has been destroyed by bacteria.

In various wasting diseases, there is a very practical indication to determine exactly the amount of waste of nutrients in the alimentary canal, although the difficulty and expense of the examination and the fact that the loss by bacterial activity is an unknown element, usually prevent such examinations. However, something may be determined by ordinary chemic tests and by macroscopic and microscopic examination, within the abilities of the clinician.