The digestibility of a food depends upon the degree to which its nutrients (nourishing constituents) can be secured from it by the body when in health. Digestibility of foods determines therefore the nourishment they yield. Science finds that all food-constituents, even in the same food, are not equally digestible. In food in general 91% protein is digested, 95% fat, 98% carbohydrate.

Digestibility Of Nutrients Of Different Groups Of Foods

In Mixed Diet

%

In Foods Eaten Separately

T

V

A

Meat

Eggs

Milk

Cereals

Legumes

Vegetables

Fruits

Sugars

Starches

92

84

97

Protein

97

97

97

85

78

83

85

95

90

95

Fat

95

95

95

90

90

90

90

97

97

98

CH

98

98

97

95

90

98

98

T, total; V,vegetable; A, animal food. Meat includes fish; milk includes butter. (After Atwater)

Comparison Of Digestibility Of Nutrients Of Specific Foods

%

Bread White

Whole Wheat

Potatoes

Beans

Peas

Bananas

Protein

88

83

75

80

83

85

Fats

90

98

90

CH

98

95

99

97

95

90

(After Olsen)

Note different breads. Remember refuse and water are not included in nutrients of foods. The percentages given above are the usable proportion of the solid nourishing parts of foods.

Time Of Digestion Of Animal Foods (After Thompson)

Eggs (raw) 1 1/2 hr. Eggs (cooked) 3 1/2-5 hr. Mutton (raw) 2 hr. Pork (cooked) 3 hr.

Beef (raw or finely chopped) 2 hr. Beef (rare) 2 1/2 hr.; (well-done) 3 hr. Beef (thoroughly roasted) 4 hr. Veal (cooked) 2 1/2 hr.

Some foods digest quickly and easily. Meats do. A food may digest relatively fully yet require much time and energy in digesting it. Cheese and beans do.

Order of Digestibility of Animal Foods (Page 218)