: Such vegetables as potatoes, squash, beets, etc., have a
certain amount of inedible material, skin, seeds, etc The amount varies
with the method of preparing the vegetables, and cannot be accurately
estimated The figures given for refuse of vegetables, fruits, etc., are
assumed to represent approximately the amount of refuse in these foods
as ordinarily prepared.]

[Footnote E: Fruits contain a certain proportion of inedible materials,
as skin, seeds, etc., which are properly classed as refuse. In some
fruits, as oranges and prunes, the amount rejected in eating is
practically the same as refuse. In others, as apples and pears, more or
less of the edible material is ordinarily rejected with the skin and
seeds and other inedible portions. The edible material which is thus
thrown away, and should properly be classed with the waste, is here
classed with the refuse. The figures for refuse here given represent, as
nearly as can be ascertained, the quantities ordinarily rejected.]

[Footnote F: Milk and shell.]

[Footnote G: The average of five analyses of cereal coffee grain is:
Water 6.2, protein 13.3, fat 3.4, carbohydrates 72.6, and ash 4.5 per
cent. Only a portion of the nutrients, however, enter into the infusion.
The average in the table represents the available nutrients in the
beverage. Infusions of genuine coffee and of tea like the above contain
practically no nutrients.]

CHAPTER XVII

DIETARY STUDIES

244. Object of Dietary Studies.--The quantity of food which different
families purchase varies between wide limits; a portion being lost
mechanically in preparation and a still larger and more variable amount
in the refuse and non-edible parts. If a record is made of all foods
purchased and the waste and non-edible portions are deducted, the
nutrients consumed by a family may be calculated by multiplying the
weight of each food by the average composition. If such calculations be
made, it will be found that in some families nearly a half pound per day
of both protein and fat is consumed by adults, while in other families
less than half of this amount is used. The object of dietary studies is
to determine the source, cost, composition, and nutritive value of the
foods consumed by different families; they also enable comparisons to be
made of the amounts of nutrients purchased. Extensive dietary studies
have been made by the United States Department of Agriculture, and the
results have been published i