The implications of cooking foods and methods used

Part Two

The effects of cooking on digestion time

The influence of cooking is seen in the following table taken from Beaumont.

Raw whipped Eggs digested in 1½ hours.

Raw Eggs (ordinary) digested in 2 hours

Soft-boiled Eggs digested in 3 hours

Hard-boiled digested in 3½ hours

Later results suggest that raw eggs are so bland they leave the stomach partly like water. The heating process coagulates or clots the chief constituent of the egg, and renders it no longer soluble in water. The longer it is boiled the more insoluble it becomes, and the longer is its period of digestion. This is worth noting, because a similar change is produced in the protein in meat by cooking. If the meat is subjected for any length of time to the temperature of boiling water (100C, or 212F), all its protein becomes changed into the insoluble form, and its ease of digestion is consequently diminished. This was confirmed by several experiments in which meat, raw or cooked in various ways, was withdrawn by means of a stomach pump after the lapse of varying times, so that the rapidity of digestion could be seen and measured. The different kinds of meat were all taken on an empty stomach, so that the presence of other foods would not confuse the readings. These were the results:

Raw Beef digested in 2 hours.

Boiled Beef (half done) digested in 2½ hours

Boiled Beef (well done) digested in 3 hours

Roasted Beef (half done) digested in 3 hours

Roasted Beef (well done) digested in 4 hours

Raw Mutton digested in 2 hours

Raw Veal digested in 2 ½ hours

Raw Pork digested in 3 hours

This shows that the more thoroughly meat is cooked, the longer is the time required for its digestion. Raw or half-raw meat is therefore preferable to well done meat. But then there arises the risk of being supplied with meat containing the eggs of intestinal worms, which thorough cooking would render harmless.

Vegetables. Most vegetable foods, however, need to be well cooked for their digestion. The cellulose which envelops starch grains and of which vegetable cell walls are made, is not soluble in the digestive fluids. It is only by the process of cooking that it is ruptured, and the contents of the cellulose envelope are allowed to come into contact with the digestive enzymes. Even such processes as juicing, are only about 50% efficient in this regard.

Cooking has other actions which aid digestion, especially the production of flavouring qualities in food-stuffs.

Aids to Digestion

Condiments. There is no question that condiments such as mustard, pepper, etc, stimulate the digestive process. Experimental physiology shows that condiments act through the organs of taste and also by direct local action on the gut’s mucous membrane. Appetite is thus excited, and secretion of gastric juice encouraged.

In one or two of the trials all flavouring materials were removed from the food before it was given. It was thus rendered tasteless and insipid, and was eaten without relish, indeed with distaste and almost repugnance, by the study participants, and yet its digestion was not impeded. In the case of the healthy, therefore, only the milder kinds of flavourers or appetizers ought to be used.

On the other hand, if someone has little appetite or a feeble digestion, there is no doubt such appetizers are valuable, not only because of the boost they give to the appetite, but also because, by their stimulating action on the mucous membrane, they excite increased flow of blood to the part, and increased secretion of digestive juices, with consequent increase of the digestive capacity.

Tea, Coffee, and Cocoa. The influence of these beverages is on the whole to retard digestion partly on account of dilution and partly on account of the action of tannic acid. Digestion of starch and protein may be retarded most by tea, less by coffee, and not at all by cocoa. (NOTE: I normally drink cocoa (BG))

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