Von Willebrand, 1908

Although the observations were carried out on obese patients rather than on normal individuals, the experiments of von Willebrand1 are of interest, since he studied the metabolism both before and after the ingestion of sugar and protein. The experiments have the single defect of the experiments made with the Sonden-Tigerstedt chamber in that the oxygen consumption was not determined and the conclusions with regard to energy transformations are accordingly based upon the carbon-dioxide excretion. This was found for obese patients to be similar to the increase noted with healthy persons, and von Willebrand concludes that the increase in metabolism after food is just as great with obese as with normal individuals. The fact that two of the subjects showed a relatively slight increase after protein is less significant because of his statement that all of his subjects were not as well trained to complete muscular repose as were those of Koraen.

Durig, 1909

With the accuracy characteristic of all his work, Durig2 reports a series of experiments made in Vienna and on Monte Rosa, in which sugar was given, the main object of the experiments being to study the influence of altitude upon the rise in metabolism following the ingestion of sugar. The logical method of securing basal values immediately preceding sugar was followed in all cases. In one of the Vienna experiments, after 120 grams of glucose the heat output increased from an average of 1.032 calories per minute to a maximum of 1.338 calories in the first hour after the ingestion of sugar. At the end of 5 hours the metabolism was still approximately 6 per cent above the basal value. In one of the Monte Rosa experiments the heat output increased after the same amount of sugar from a basal value of 1.257 calories per minute to a maximum of 1.463 calories in the first hour after feeding. In the fourth hour the basal values were again reached. The respiratory quotients did not exceed unity in any case.

1von Willebrand, Skand. Arch. f. Physiol., 1908, 20, p. 152. 2Durig, Denkschr. d. Wiener Akad. d. Wiss., 1909, 86, p. 116.

Gigon, 1909

An important contribution from the Stockholm laboratory on the influence of protein and carbohydrate ingestion upon metabolism was published by Gigon1 in 1909. Since it is well established that both sugar and protein cause an increase in the carbon-dioxide production, the experiments were especially designed to study the influence of a combination of sugar and protein. As was usual with the experiments in the Stockholm laboratory, the carbon-dioxide excretion alone was determined. The fasting value was found to be 23.8 grams carbon dioxide per hour. After 46 grams of dextrose this increased to 29.9 grams, and in experiments with 16 grams casein it increased to 28 grams. When these same amounts of dextrose and casein were given together, the carbon dioxide rose to 34 grams. Since the increase in the carbon-dioxide production in the last series of experiments was practically the sum of the increments noted in the dextrose and casein experiments, the author concludes that there is a summation effect. Furthermore, if carbohydrate or protein is taken in several equal amounts at regular intervals, the increased carbon-dioxide production remains at an unchanged height for several hours. The author concludes with an interesting discussion of the Verdauungsarbeit and the specific dynamic action theories, defending the latter.

Gigon, 1911

The most extended discussion of the influence of food on the metabolism of man since the research of Magnus-Levy was contributed by Gigon in 1911.2 His research, which was carried out with himself as the only subject, and exclusively with pure food materials, was made in part with the Sonden-Tigerstedt respiration chamber in Stockholm, and in part with the Jaquet respiration chamber in the Medical Clinic in Basel. A few basal metabolism experiments,3 but no food experiments, were made with a respiration apparatus employing the mouthpiece, Muller valves, and spirometer in the Poliklinik in Basel.

Unfortunately, as has been frequently pointed out, the Stockholm experiments do not include determinations of the oxygen consumption. This deficiency in experimental methods is of special significance in considering the question of carbohydrate ingestion; it likewise renders problematical the calculations and assumptions made by Gigon with regard to the character of the katabolism both during the fasting period and after food.

1Gigon, Skand. Arch. f. Physiol., 1908-09, 21, p. 351.

2Gigon, Munchen. med. Wochenschr., 1911, 58, p. 1343; and Arch. f. d. ges. Physio!., 1011, 140, p. 509. See Gigon, Munchen. med. Wochenschr., 1911, 58, p. 1343.

Gigon's main contention is that the basal resting metabolism is extraordinarily constant with the same individual over long periods of time. What is even more striking, he claims that the character of the katabolism as apportioned between protein, fat, and carbohydrate is also constant. Most of the experiments in Basel were made during sleep. Gigon concludes that the gas exchange in sleep is perfectly comparable to that "bei vorsatzlicher Muskelruhe." For the Basel average nuchtem values he uses for the energy output 22.5 calories per kilogram per 24 hours, for the carbon-dioxide excretion 23.356 grams per hour, and for the oxygen consumption 21.05 grams per hour.

In the protein experiments made in Stockholm, casein was used, hourly doses of 15.56 grams of this food material increasing the carbon-dioxide excretion 4.2 grams per hour (the Stockholm nuchtern value of 23.8 grams being used as the basal value). In Basel, with the Jaquet apparatus, the casein was given in 50-gram portions, resulting in an average increase of 5.03 grams carbon dioxide (6.1 per cent) for a period of approximately 3 1/2 hours. Subsequently 100, 150, and indeed 200 grams casein were given; in all instances very considerable increases not only of carbon dioxide but of oxygen were noted. The increment for the carbon-dioxide excretion was 15.5, 22, and 26 per cent of the nuchtern value, following 100,150, and 200 grams of casein respectively. For the oxygen production, 50 grams casein gave 7.4 per cent increase, 100 grams gave 14 per cent, 150 grams gave 22.1 per cent, and 200 grams gave 27.1 per cent increase. Thus when the size of the portion was varied in the ratio of 1 : 2 : 3 : 4, the carbon-dioxide production increased in the ratio of 1 : 4 : 8 :12 and the oxygen intake increased in the ratio of 1 : 3 : 6 : 9. It should be pointed out that the experiments varied considerably in length and hence a comparison of the various amounts of protein is somewhat uncertain. Gigon contends that the combustion of fat and carbohydrate remains unchanged from the nuchtern value when casein is taken.

In the Stockholm sugar experiments 46 grams of sugar per hour were given, this amount producing an increase of 6.1 grams per hour in the carbon-dioxide production. On the assumption that the carbon-dioxide excretion can be taken as an index of the metabolism during the dextrose experiments, Gigon computes a metabolism of about 90 calories per hour or about 20 calories above the normal. In Basel two experiments were made, one with 100 and one with 50 grams of sugar, the 100 grams giving twice as great an increase in the carbon-dioxide production as the 50 grams. In the 2-hour experiments in which 50 grams of dextrose were taken the total heat production was 156 calories, or 6 calories per hour above the nuchtern value. In a 4 1/2hour experiment with 100 grams dextrose an increase of 30 calories over the nuchtern value was found, or approximately 6 to 7 calories per hour. In support of his contention that the basal metabolism is unaffected by the ingestion of food, Gigon points out that in the glucose experiments the course of the nitrogen and the phosphoric-pentoxide excretion is practically uninfluenced by dextrose.

His observations on the ingestion of fat are of special significance, for at least 2 experiments with 50 grams of olive oil showed a distinct depression of the basal metabolism. With 150 grams of oil the metabolism was slightly above the basal value. Contrary to the experience in most laboratories, with a change to a fat diet Gigon noted that there was a decrease in the nitrogen excretion in the urine. This depression of the metabolism is explained by Gigon as being due to the fact that even during fasting there is always a certain amount of Verdauungsar-beit, and that the ingestion of oil depresses this, thus affecting the basal value. A careful theoretical discussion is given of the two prevailing views regarding the cause for the increased heat production after food, namely, the Verdauungsarbeit theory of Zuntz and the specific dynamic action theory of Rubner.

In discussing the carbohydrate ingestion, Gigon points out that his experiments usually show that there is no increase in the respiratory quotient and that the increase in the gaseous exchange noted must be due to a cause other than an increased combustion of sugar; in most of Gigon's experiments there is little basis for the theory of fat formation from sugar. In discussing the increase following protein disintegration, Gigon concludes that the total protein disintegration does not exceed that of the nuchtern value, and that in all probability there is considerable fat formation from protein, together with a small carbohydrate formation.

Finally, following the general contention of Johansson, Gigon maintains that the food is first deposited in the body in different depots, which, in turn, furnish the energy for cellular activity. Since these depots must in large part rely upon fat formation, Gigon points out that there is probably a considerable fat formation and that fat plays a larger role in the metabolism than has heretofore been supposed.