HOME ECONOMICS AND EDUCATION 647 



standards can easily make a simple dietary study in her home, and 

 by so doing can perhaps not only provide meals that are more in 

 accordance with the needs of her family, but frequently also save 

 money by substituting less expensive but equally nutritious and at- 

 tractive food materials for some of those usually served. 



The simplest way to make such a study is to weigh all different 

 kinds of food materials in the house at a given time, say after supper, 

 recording the weights in a convenient book. All the food purchased 

 during the days during which the diet is being studied is weighed 

 and recorded, and at the close of the study, which may be conveni- 

 ently of seven or ten days' duration, all food materials remaining on 

 hand are weighed as before. From the quantities of the different 

 kinds of food on hand at the beginning and purchased during the! 

 period are subtracted the quantities left on hand at the close of the 

 study. The difference represents the amounts used. The quantity 

 of nutrients in the different materials is calculated from the figures 

 for percentage composition given in Table I. In order to express 

 the quantities of nutrients in values per man per day, the number 

 of meals taken by different members of the family are multiplied 

 by the factors for age, sex and work, pointing off two decimal places. 

 The result gives the equivalent number of meals taken divided by 

 3 gives the equivalent number of days for one man. The total 

 nutrients for the whole period, divided by this latter quantity, gives 

 the nutrients per man per day. From these latter figures the fuel 

 value of the diet can be computed. In a similar way the value of 

 any menu for one day or one meal may be calculated, but in a short 

 period, such as a day or two days, the diet may vary according to 

 the materials used so as to give more of one kind of nutrients and 

 less of another, or more or less total nutrients than the average diet, 

 while in periods of a week or ten days the diet is more likely to 

 approach an average. 



ADAPTING FOOD TO BODILY NEEDS. 



All persons need protein for building and repair of the body 

 and fuel ingredients for warmth and work, but individuals differ 

 in amounts and proportions of requirements. 



For people in good health and with good digestion there are 

 two important rules to be observed in the regulation of the diet. 

 The first is to choose the things which agree with them, and to 

 avoid those which they can not digest and assimilate without harm. 

 The second is to use such kinds and amounts of food as will supply 

 all the nutrients the body needs and at the same time avoid burden- 

 ing it with superfluous material to be disposed of at the cost of health 

 and strength. 



For guidance in this selection, nature provides us with instinct, 

 taste, and experience. Physiological chemistry adds to these the 

 knowledge still new and far from adequate of the composition of 

 food and the laws of nutrition. In our actual practice of eating we 

 are apt to be influenced too much by taste. 



The theory is advanced from time to time that one or two 

 meals a day are preferable to the three commonly served. The 



