The nutrition of man / Russell H. Chittenden.

  • Chittenden, Russell H. (Russell Henry), 1856-1943.
Date:
1907
Catalogue details

Licence: Public Domain Mark

Credit: The nutrition of man / Russell H. Chittenden. Source: Wellcome Collection.

    31/362 (page 15)
    per gram,1 or 5.7 large calories. Deducting the heat value of the proteid decomposition products contained in the ex¬ creta, the physiological fuel value of proteids is reduced on an average to about 4.1 large calories per gram.2 Rubner considers that the physiological fuel value of vegetable pro¬ teids is somewhat less than that of animal proteids; con- glutin, for example, yielding 3.96 calories, as contrasted with 4.3 calories furnished by egg-albumin, or 4.40 calories from casein. On a mixed diet, where 60 per cent of the ingested proteid food is of animal origin and 40 per cent vegetable, the fuel value available to the body would be about 4.1 calories per gram of proteid, on the assumption that the physiological heat value of vegetable proteids aver¬ ages 3.96 calories per gram and that of animal proteids 4.23 calories per gram (Rubner). At present, we accept for all purposes of computation the following figures as representing the physiological or avail¬ able (to the body) fuel value of the three classes of organic foodstuffs: 1 gram of proteid.4.1 Large Calories 1 gram of fat.9.3 “ “ 1 gram of carbohydrate.4.1 “ “ From these data, it is evident at a glance that 1 gram of fat is isodynamic with 2.27 grams of either carbohydrate or proteid; and since carbohydrate and fat are of use to the body mainly because of their energy value, it is obvious that 50 grams of fat taken as food will be of as much service to the body as 113 grams of starch. In view of the relatively high fuel value of fats, it follows that the physiological heat of combustion of any given food material will correspond 1 Stohmann: Ueber den Warmewerth der Bestandtheile der Nahrungsmittel. Zeitschr. f. Biol., Band 31, p. 373. 2 See Rubner : Calorimetrische Untersuchungen. Zeitschr. f. Biol., Band 21, p. 250. Also, Rubner: Die Quelle der thierischen Warme. Ibid., Band 30, p. 73.