Food Characteristics that affect digestibility of food are in general:

Structure Of Food (How Food-Constituents Are Held In Food)

Texture (fineness and compactness; coarseness and looseness). Finegrained food understimulates the digestive tract. Coarse may render it overactive, resulting in elimination of food undigested.

Properties of food, as salts in milk and eggs, aid in keeping blood in condition for effective assimilation of food. Enzymes in food also aid digestion. Pineapple contains such an enzyme. It furthers the digestion of other foods. (Place a piece of meat between 2 slices of pineapple. Leave over-night. Examine next day.) Laxative foods contain substances that increase peristalsis.

Palatability

Unappetizing food may decrease digestive juices.

Digestibility of food may be furthered by:

Preparation in cooking, that breaks up food, making it ready for digestion, and destroys bacteria that might disturb digestion or cause disease.

Mastication of food breaks it up and so exposes it to the digestive juices.

Combining foods so that digestive tract is used as a whole, as in mixed diet. Also supplementing foods deficient in any food-constituent with others containing this, as rice (often lacking in salts) with egg-yolk, barley foods, and lentils that add such salts as those lost.

Quantity adjusted to need. Too little or too concentrated food in lacking bulk may cause constipation. Too much or excess of bulky food stretches and weakens the stomach, clogs the body with waste products, and causes food-fermentation. With a moderate amount of food 1/15 to 1/14 more food is digested and is also more easily digested.

Time and energy are both required to digest food. Different amounts of both are needed for different foods. Too rapid and too frequent eating as well as too much food weaken digestion. Adults usually need food 3 times daily at intervals of 4 to 5 hours.

Food as eaten excites the flow of digestive juices, especially acid, liquid, or sweet foods. Soups act thus at the beginning of a meal.

Water, a glassful at the beginning of a substantial meal, increases flow of digestion juices and renders them more destructive to bacteria. (Hall)

Acids, fruits, or acid fluid food, as lemonade, in moderate quantity near the end of a meal, stimulate flow of gastric juice and increase the acid in it, so further digestion of food. (Hall)