We found from the previous chapter that in infectious diseases the dietitian has to deal with disturbances of the metabolism, while the digestive system is, as a rule, in a fairly normal condition and able to digest a sufficient amount of food to keep the system sufficiently nourished. In the treatment of diseases of the digestive system, however, the physician and attendants are confronted by difficulty of another character. Any disturbance of metabolism is purely secondary; it is the gateway to the nutrition that is out of order, and diseases of the digestive system, whether they are functional or organic, interfere with the processes of nutrition at the very outset. Aside from pain sometimes experienced in various disorders of the digestive system, the principal symptoms are those associated with the incomplete digestion and absorption of food.

In a general way, the cause of diseased conditions of the digestive system is bad hygiene. For example, overeating, irregularity of meals, bolting the food, or failure properly to masticate the food, and wrong choice of food. Other conditions not conducive to normal work of the system, such as heavy work, either physical or mental, immediately following heavy meals, or the reverse, the eating of a heavy meal immediately following exhausting work. The rational treatment of the digestive system should always begin with a study of the cause of the condition in a particular case. Once the cause is determined, it should be removed. This alone would in a considerable proportion of the cases lead gradually to a regaining of the normal condition. Any loss of weight in these cases is very likely to indicate a failure to assimilate a sufficient amount of food, while in the group of cases discussed in the preceding chapter loss of weight indicated increased metabolism beyond the normal.

A general rule may be set down for all these cases of disturbance of the digestive system: If the condition is very acute in its onset and if the patient is in a well-nourished condition, when overtaken by the disease, the best initial treatment would be a complete rest for the digestive system for a period of forty-eight to seventy-two hours. In the chronic cases and all cases that begin very gradually, the physician and dietitian are not called in until there is already a considerable disturbance of nutrition, usually with decided loss of weight. In these cases the initial fast is con-traindicated.