The gain in weight after a fast is usually very rapid. Often it is almost as rapid as the loss during the fast. People that were formerly always underweight and emaciated, due to impaired digestion and assimilation, will become normal in weight.

Studying the liver cells of a fasting salamander, Morgulis found that after four days of feeding both cells and nuclei had gained 34 and 31 per cent respectively. In another four days, eight days in all, the cell body had increased 143 per cent. After only fourteen days of feeding, the liver nuclei had reached normal size although the cells were still under sized.

The epithelial cells lining the duodenum increased even more rapidly than did the liver cells. Their bodies and nuclei increasing 45 and 24 per cent respectively in the first four days of feeding. He says "the same holds true for the regeneration of the pancreatic cells except for minor details of the process."

These gains were seen after four months without food, during which time the body as a whole lost 50 per cent. The liver cells, being food reservoirs, lost 52 per cent the first month, 74 per cent in two months and 80 to 85 per cent in three months.

Morgulis says: "the recuperation of the cells is shown when the animals are nourished again after having fasted three and a half months. The regeneration of the cells is marvellously rapid, the original normal condition being practically restored after 14 days of feeding."

Protozoa show an astounding capacity for recuperation when feeding is resumed after an enforced fast. Some of them regain normal size in only two days. Other forms require as much as fifteen days. Recovery "is the inverse of that during inanition." Cell-divisions begin three to five days after feeding is resumed.

Carlson and Kunde found that at the end of a fast, subjects are able to maintain themselves and even gain weight on much smaller amounts of food than they had formerly thought necessary to keep them going, thus corroborating in the laboratory, a fact of observation that every one experienced in conducting fasts has seen many times.

Kunde says: "It seems that the mechanism by which the cells of an extremely emaciated body, rendered thus by starvation (fasting) but organically sound, utilizes food must be quite different from that which occurs after emaciation from sickness, when not only body substances must be built up, but functional disturbances as well. Certainly the body is not able to utilize food on such an economical basis under ordinary conditions of nutrition."

It is not necessary to assume that the "mechanism" of food utilization is different in emaciation produced by fasting from that produced by sickness. We need only to recognize that it is less efficient after sickness because of damages from toxins, drugs and from functional weaknesses. On the other hand, we need to know that rapid gains in weight do often follow sickness and this is especially so if the sickness was accompanied by fasting.

Carlson and Kunde give one case where a subject gained 17.38 lbs. in the first seven days after the completion of a fast, and the body weight came back to normal despite the fact that during the first five days after the fast only one meal a day was eaten, and that a very moderate one.

But it would be impossible to gain so much weight in such a short time without consuming enough food to put on this much weight, unless excessive water drinking produced a water-logged state of the tissues. There was either over-eating or over-drinking or both, and thus, much of the benefits of the fast were destroyed. Another of Carlson and Kunde's fasters gained 17.2 lbs. during the first week after a fast. Such rapid gains are not desirable.

Mrs. Sinclair lost twelve pounds in ten days during her first fast, and then gained twenty-two pounds in seventeen days following the fast.

Mr. Sinclair gained four and a half pounds on the third day after breaking his fast. In twenty-four days he gained a total of twenty-two pounds. This gain, be it noted, followed a twelve days fast, which occasioned a loss of seventeen pounds. He tells us, "I had always been lean and dyspeptic looking, with what my friends called a 'spiritual' expression. I now became as round as a butter-ball, and so brown and rosy in the face that I was a joke to all who saw me."

There is no reason why the emaciated person should not fast. Indeed, there is often every reason why he should. The fast is sometimes the only thing that will enable him to gain weight.

Special weight gaining diets are not required. The milk diet is frequently employed after a fast to force a rapid gain in weight. This I consider not to be necessary, but as tending to actually undo some or all of the benefits derived from the fast.

Von Seeland subjected chickens to intermittent short fasts, using mature birds for this purpose. These fasts lasted one to two days. His fasting birds, although getting less food than the control birds, became heavier than the latter. He states that the increase in weight was due to an increase in real flesh--protein material--and not to a mere increase in fat. He states that the periodic fasting makes the body heavier, stronger and more solid. Morgulis experimenting with salamanders secured opposite results. "Kagan found," says Morgulis, that "the power of resistance declines with each new experience of starvation. The organism which recovered from inanition through the consumption of a liberal quantity of food still shows the effects of the previous experience * * * and when the inanition is repeated dies sooner than the normal organism."

While Dr. Morgulis thinks that the results of his experiments and those of Kagan, contradict the results claimed by Von Seeland, he says, "they do not necessarily disprove his contention of the invigorating influence of brief fasts inasmuch as in our own experiments the duration of each fast was considerably greater."

It should be quite obvious that a series of intermittent fasts must not be long ones. It is quite obvious that subsequent recovery will depend upon the character of the food eaten as well as upon other factors, such as sunshine, exercise, etc. Much depends, too, upon the length of the period between the fasts. We frequently put patients upon intermittent short fasts and secure just such results as Von Seeland reports in his chickens.

Morgulis says that his intermittently fasted salamanders--"with one-half the amount of food reached somewhat more than two-thirds of the body weight of the continually fed salamanders." This points to a remarkable improvement in nutritive power and function, but it is too much to ask one-half the amount of food to produce greater results. Von Seeland did not limit his fasting chickens to one-half the food eaten by the control chickens.

Fasting is not something to be played with. It is only a part of the health program. Feeding after the fast and the general hygienic care of the patient are even more important. Laboratory experimenters, with their antiquated and synthetic diets, certainly are not to be trusted in this matter of feeding after a fast.

I am convinced, from my own experience with patients, that a too rapid gain in flesh following the fast does not build as solid and healthful flesh as a slow rate of gain. Milk diet enthusiasts produce a flesh-gain after a fast, by their over-feeding, which is almost as rapid as the loss during the fast. But such flesh is watery, flabby and soon lost when one becomes active and returns to other foods. I prefer to feed patients an abundance of fresh fruits and green vegetables and limited quantities of proteins, starches and fats. Flesh gained at a slower rate is more solid and stays with the patient. A too rapid growth in children is not productive of sound tissue. I am convinced that the same is true of a too rapid gain after a fast.

A few do not gain rapidly for more than a week or two weeks after breaking the fast. With many, a short fast does not suffice to occasion a gain in weight. Many factors are at work to prevent a gain in these cases and the short fast is not sufficient to restore the nutritive functions to a vigorous state.

The most rapid gains in weight are seen after a long fast. All cases, however, will gain at a fairly rapid rate if the underlying causes of defective nutrition are corrected. This depends on many factors other than fasting and the intelligent person, be he doctor or patient, will not fail to attend to all necessary factors and influences.

In those animals that periodically undergo protracted periods of fasting, a tendency to acquire, during the feeding season, large stores of fat, is seen. Among these animals, as the Russian bear and the Alaskan fur-seal bull, the period of abstinence from food is often of long duration, so that a large supply of nutriment is necessary. Frequent fasting in man may result in the same tendency although I have never seen a clear case of the development of such a tendency from repeated fasts.