1. Never Eat Carbohydrate Foods And Acid Foods At The Same Meal.

Do not eat bread, potatoes, or peas, or beans, or bananas, or dates, or other carbohydrates with lemons, limes, oranges, grapefruits, pineapples, tomatoes or other sour fruit.

The enzyme, ptyalin, acts only in an alkaline medium; it is destroyed by a mild acid. Fruit acids not only prevent carbohydrate digestion, but they also favor their fermentation. Oxalic acid diluted to one part in 10,000 completely arrests the action of ptyalin. There is enough acetic acid in one or two teaspoonfuls of vinegar to entirely suspend salivary digestion.

Dr. Percy Howe, of Harvard, says: "Many people who cannot eat oranges at a meal derive great benefit from eating them fifteen to thirty minutes before the meal." But Dr. Howe does not appear to know why these people cannot take oranges with their meals. I have put hundreds of patients, who have told me that they could not eat oranges or grapefruit, upon a diet of these fruits and they found that they could take them. Such people are in the habit of taking these foods with a breakfast of cereal, with cream and sugar, egg on toast, stewed prunes and coffee, or some similar meal.

Tomatoes should never be combined with any starch food. They may be eaten with leafy vegetables and fat foods. The combination of citric, malic and oxalic acids found in tomatoes, (which are released and intensified by cooking), is very antagonistic to the alkaline digestion of starches in the mouth and stomach. They should not be used on salads at a starch meal.

The physiologist, Styles, runs from the practical application of our knowledge of the chemistry of digestion by saying: "If the mixed food is quite acid at the outset, it is hard to see how there can be any hydrolysis (enzymic digestion of starch) brought about by the saliva. Yet we constantly eat acid fruits before our breakfast cereal and notice no ill effects."

That we "notice no ill effects," from such acid-starch combinations, is true only of those who give no attention to the matter. All students of food combining know that this combination does produce ill effects. Stiles would, of course, say that these ill effects are due to germs.

He continues: "Starch which escapes digestion at this stage is destined to be acted upon by the pancreatic juice, and the final result may be entirely satisfactory." It is true that the starch will later be acted upon by the pancreatic and intestinal enzymes, providing it has not previously been acted upon by bacteria, the thing that usually occurs, giving us gas and a sour stomach and the notion that: "I cannot eat oranges or grapefruit. They give me gas."

Assuming, for the sake of argument, that no fermentation occurs, are we to assume, also that salivary digestion is of so small consequence that we can afford to dispense with it altogether? I do not think so and Stiles himself hints the same, when he adds: "Still it is reasonable to assume that the greater the work done by the saliva, the lighter will be the task remaining for the other secretions and the greater the probability of its complete accomplishment."

In cases of hyperacidity of the stomach there is great difficulty in digesting starches. Much discomfort is caused by eating them. They ferment and poison the body. Acid-starch combinations are very rare in nature--the sour apple coming nearest to being such a combination.

The highest efficiency in digestion demands that we eat in such a way as to offer the least hindrance to the work of digestion and not that we seek flimsy pretexts for continuing our customary haphazard eating. We should make the best use of our knowledge of the chemistry and physiology of digestion and of the limitations of the digestive enzymes and not try to ignore this knowledge altogether. This is particularly important in diseased states and in cases of crippled digestion.

Is it true that the pancreatic juice will digest starch when the first step in the process has not been made by the ptyalin? It is asserted by some that ptyalin is the only agent in the body capable of initiating the digestion of starch. Whether or not this is true, certainly salivary digestion is not to be regarded as unimportant. For, when it fails to occur, fermentation is practically certain to take place.