NUTEITION INVESTIGATIONS. 



467 



the kind and amounts of the different nutrients required by the 

 standards. A slight deficiency one day will be made good by an excess 

 the next, the body serving as a storehouse for reserve material. 

 Experience has, however, shown that the body is best nourished 

 when through long periods the food approximates the requirements 

 of the so-called standards. Individual requirements and individual 

 peculiarities will always affect the choice of foods. In the purchase 

 of other things their value for the purpose for which they are intended 

 is considered as well as their cost. Without doubt the same principle 

 may be advantageously applied to the purchase of food. By the 

 exercise of a wise economy, based on a knowledge of the real nutri- 

 tive value of foods, a more satisfactory diet can be obtained for a less 

 sum than is at present expended in many cases, or the cost of the diet 

 may be diminished without lessening its nutritive value. 



COMPOSITION OF FOOD MATERIALS. 



One outcome of the nutrition investigations is that we have to-day 

 a tolerably clear knowledge of the composition and nutritive values 

 of our ordinary American food materials. Taking into account not 

 only the results of analyses but also of digestion experiments, we are 

 able to prepare tables showing the average quantities of digestible 

 nutrients in a large number of the food materials in most common use. 

 The table herewith is an illustration of this: 



Nutrients and energy of digestible portion of some common foods, with nutritive ratios. 



