Professor Irving Fisher of Yale University has elaborated a very ingenious mechanical method of estimating diet by an apparatus which automatically finds the center of gravity of small weights representing units of 100 calories each. Unfortunately, this method requires that the analysis of all dishes shall be made with a fair degree of accuracy and that each serving shall be weighed out in the kitchen, also that the patient shall eat the whole or a definite fraction or multiple of any serving, or that waste shall be accurately weighed. Thus, the method is applicable only to institutions, and even then must be considered as merely approximate.

However, Fisher's table of 100-calorie units is a very convenient basis of a general conception of a standard diet, either in health or disease, and the computations may be made arithmetically, instead of by the gravity-instrument. In using the appended table, it must be remembered that the protein, fat and carbohydrate percentages of the 100-calorie units, represent calories produced from each of these organic ingredients, without allowance for either ingestive or digestive waste, and that the units vary in actual weight. Thus, if it is desired to know the number of grams of protein in a unit, we must first divide the protein-calorie percentage by 4.9 (the number of calories produced by the oxidation of a gram of protein) and must then multiply the actual weight of the 100-calorie unit by this new percentage. Similarly, the fat-calorie percentages must be divided by 9.3 and the carbohydrate-calorie percentages by 4.1.

It is obvious that the average adult requires, according to the amount of exercise, exposure to cold, etc., somewhere between 22 and 30 of these 100-calorie units in a day, and that, to insure that the protein does not fall below 50 grams nor exceed 100 grams, the total of protein calories should lie between about 250 and 500. Also, it is obvious from the general principles already discussed, that the fat calories should preferably be less than 1000, and that, to avoid fatty- acid intoxication, the carbohydrate calories should amount to 325. Ordinarily, they should lie between 1200 and 2000, the latter being a rather large allowance.

An ideal standard diet would consist of 250 protein calories, 500 fat calories and 1500 carbohydrate calories, for a professional or business man, taking very little exercise. The same man, taking considerable exercise, would require up to 300 protein calories, and a total of about 2500 calories, which could be distributed without danger in any way, providing that the limits mentioned in the last paragraph are not exceeded in any case.

The following diet table would be considered, by most men, as rather abstemious, and yet it is ample for one not performing manual labor.

(Note that the sum of the protein, fat and carbohydrate calories agrees within .1, the slight error being due to the fact that divisions of portions were carried out only one decimal place.)

A hearty eater, still far removed from what is ordinarily considered gluttony, would add to the above dietary, for breakfast, 2 large or 3 small eggs (2 100-calorie portions), another cereal serving of some sort (1 portion), a banana (1 portion), and, through the day, 3 butter balls (3 portions), an additional serving of meat (1 portion), an additional serving of some vegetable (1 portion), 1.5 cubic inches of cheese (1 portion), 3 or 4 olives (1 portion), 8 almonds (1 portion), 3 Brazil nuts (1 portion), 8 pecans (1 portion), a piece of cake or doughnut (2 portions), and extra serving of dessert (1 - 4 portions), and say an eighth of a pound of candy (2 portions). Here we have an addition of 19 - 23 portions, or very nearly the total calories required altogether.

Many persons cat 30 - 60 grams of butter at a meal, i. e., approximately 1/3 -2/3 the entire daily ration of calories. The caloric value is particularly high for fruits, desserts, etc., which most persons fail to regard as food at all. An apple represents 50 calories ( 1/2 portion) and most servings of fruit sauces represent at least one portion. Every doughnut or piece of cake represents 2 portions, and an ordinary piece of pie 2 - 4 portions. Thus, half of the entire caloric ration mav be taken at the dessert of one meal. Many good feeders, so called, habitually eat more than double the requisite ration.