480 AMOUNT AND QUALITY OF FOOD REQUIRED. 



Proportion. With regard to the relative proportions of the various 

 kinds of food which ought to be taken, experience has shown that 

 the diet best suited for the body must contain 1 part of nitro- 

 genous foods to 3 or, at most, 4^- of the non-nitrogenous. Looking at 

 ordinary foods from this point of view, we see how far they 

 correspond to this requirement, and how several substances may be 

 combined to produce a satisfactory diet. 



Nit. Non-Nit. 



1. Veal, . . 10 ... 1 



2. Hare's flesh, . 10 ... 2 



3. Beef, . . 10 ... 17 



4. Lentils, . . 10 ... 21 



5. Beans, . . 10 ... 22 



6. Peas, . . 10 ... 23 



7. Mutton, . . 10 ... 27 



8. Pork, . . 10 ... 30 



9. Cow's milk, . 10 ... 30 



Nit. Non-Nit. 



10. Human milk, 10 ... 37 



11. Wheaten-flour, 10 ... 46 



12. Oat-meal, . 10 ... 50 



13. Rye-meal, . 10 ... 57 



14. Barley-meal, 10 ... 57 



15. White potatoes, 10 ... 86 



16. Blue 10 ... 115 



17. Rice, . . 10 ... 123 



18. Buckwheat meal, 10 ... 130 



An examination of this table shows that, in addition to human milk, wheat- 

 flour has the right proportion of nitrogenous to non-nitrogenoiis substances. A 

 man who tries to nourish himself on beef alone, commits as great a mistake as one 

 who would feed himself with potatoes alone. Experience has taught people that 

 man may live upon milk and eggs, but that in addition to flesh we must eat 

 bread or potatoes, while pulses require fat or bacon. 



The diet varies with the climate and with the season of the year. As the 

 organism must produce more heat in cold latitudes, the inhabitants of northern 

 climes must eat more non-nitrogenous foods, such as fats and sugars or starches, 

 which, on account of the large amount of C they contain, are admirably adapted 

 for producing heat (p. 442). 



The graphic representation of the composition of Foods (Fig. 175), 

 taken from Fick, shows at once the relative proportions of the 

 food constituents and how they vary from the standard of 1 

 nitrogenous to 3-J 4-g- non-nitrogenous. 



The absolute amount of food stuffs required by an adult in 24 

 hours depends upon a variety of conditions. As the food represents 

 the chemical reservoir of potential energy, from which the kinetic 

 energy (in its various forms) and the heat of the body are obtained, 

 the absolute amount of food must be increased when the body 

 loses more heat, as in winter, and when more muscular activity 

 (work) is accomplished. As a general rule an adult requires daily 

 130 grammes proteids, 84 grammes fats, 404 grammes carbohydrates. 



The following tables express the mean of numerous single observations : 



