Nuts have not been extensively studied by the biological method. Little can be said of their dietary properties other than what can be deduced from their chemical composition and from their function in the plant from which they are derived (34). With the exception of the chestnut, nuts are very rich in protein, and fat, and poor in carbohydrates. The edible portions of several of the more highly prized nuts contain the following amounts of protein: Almond 21 per cent; beech-nut 22 per cent; brazil nut 17 per cent; chestnut 6.2 per cent; pecan 11 per cent; walnut 18.5 per cent. The fat content of these nuts is on an average: Almond 55 per cent; beech-nut 57 per cent; brazil nut 67 per cent; chestnut 6.2 per cent; pecan 71 per cent; walnut 64 per cent. The digestible carbohydrate of most nuts is very small. The chestnut is unique among the ordinary nuts in that it contains about 45 per cent of starch and but little fat. Feeding studies have shown that several nuts have essentially the same dietary properties as seeds in general (34).

The flavors of nuts are especially attractive, and they form a group of highly desirable food-stuffs. They are, however, the seeds of plants and one would predict that their dietary properties are not such as to make them effective supplements for the cereals, legume seeds, tubers, roots or fruits, except in respect to the protein factor. A diet composed of such combinations of food may be chemically balanced so far as analysis can show, but be decidedly defective in other respects.