Magnus-Levy, 1894

Recognizing clearly the fact that the increment in metabolism following the ingestion of food persists only a relatively short time, Magnus-Levy,3 employing the Zuntz-Geppert respiration apparatus, carried out a most extended series of experiments on the influence of food on metabolism. Certainly no series of experiments prior to 1894 is comparable to this research, and few since that time can compare with it for accuracy or for skillful plan. Considering only those experiments made with men, we find that most of the experiments were carried out with one subject. An extensive list of basal values is reported, these values being, for the most part, very constant. Since it is necessary to consider the time element in experiments of this kind, Magnus-Levy carefully determined the basal metabolism throughout the day on three subjects and found it relatively constant, the values for the oxygen consumption falling approximately 5 per cent during the day.

1Likhatscheff, Production of heat of healthy man in the condition of comparative rest. Diss., St. Petersburg, 1893. 2d'Arsonval, Arch, de Physiol., 1894, 26, p. 360. 3Magnus-Levy, Arch. f. d. ges. Physiol., 1894, 55, p. 1.

Food experiments were made on 3 days with fat, the diet on one day being 210 grams of bacon, 30 grams of bread, and 8 c.c. of alcohol; on another day 210 grams of butter; and on a third day 100 grams of bacon. A small increase in the metabolism was noted, particularly in the later hours. In the first two experiments the increment in the oxygen consumption was from 10 to 14 per cent. In the last experiment the maximum value was but 6 per cent above the basal value.

In carbohydrate experiments carried out with four subjects, white bread was chiefly used, but one experiment was also made with pumpernickel. The increment in the oxygen consumption was positive in practically all cases. It was found that the increment in the first hour may be as high as 33 per cent; in three cases it was over 6.5 per cent even 7 hours after taking food. Eight experiments were made on man after giving from about 50 to 155 grams of cane sugar or grape sugar. The oxygen consumption, which alone may be used in measuring the increase in the total metabolism, showed in all but one case an increase during the first hour, this increase amounting in one instance to 16 per cent. In subsequent hours the values were frequently below the basal value, particularly when small amounts of sugar were given. With 100 or more grams of sugar oxygen values above basal were found; in one experiment the increment persisted for 8 hours.

Five observations were made on man after roast beef had been given in amounts varying from 120 to 310 grams. In all of the experiments the percentage increase in the oxygen consumption was very marked, the maximum occurring between the third and sixth hours. In at least three instances the increment was 20 per cent or over as late as the seventh or eighth hour, showing a marked and prolonged effect as a result of the ingestion of protein.

Three experiments were made in which the subject took a mixed diet which supplied 3,060, 2,280, and 2,150 calories, respectively. In practically all instances about 47 per cent of the energy came from carbohydrate, 33 per cent from fat, 14 per cent from protein, and 6 per cent from alcohol. The increase in the oxygen consumption was marked in nearly every case. Thus, after breakfast, the average percentage increments for 4 successive hours were 27, 27, 16, and 6 per cent, respectively; after the noon meal for 6 successive hours they were 40, 35, 27, 19, 17, and 9 per cent, respectively; after the evening meal they were 33, 23, 12, and 6 per cent for the first 4 hours, followed by slightly negative values for the remainder of the night. The average increment for the 14 hours from the first hour after breakfast until the fourth hour after the evening meal is computed as 21 per cent. The author points out that the true metabolism is really somewhat greater, since the mechanical work of chewing and swallowing is not noted in the experiments. An interesting computation is made of the total increment for the entire day, which is computed to amount to 13 per cent for the oxygen consumption and 19.75 per cent for the carbon-dioxide production.

This article, which is justly cited as a classic, represents by far one of the most critical and ambitious attempts to solve the perplexing problem of the influence of the ingestion of food upon the metabolism of human subjects. The observations on men are substantiated by even more extensive series of observations on dogs. The dominant note of the discussion is that the increase following the ingestion of food is in large part due to the work of digestion in contradistinction to the explanation of it by Rubner's theory of specific dynamic action. On the other hand, Magnus-Levy's discussion of the subject has the great advantage of giving a concrete statement as to the probable cause for the increased metabolism and consequently is more subject to direct experimental attack than is the more subtle explanation offered by the specific dynamic action theory, which in itself has undergone marked revision in recent years.

Sonden And Tigerstedt, 1895

The extensive research carried out by Sonden and Tigerstedt1 with the large respiration chamber in the Karolinska Institute in Stockholm does not lend itself particularly well to a discussion of the influence of the ingestion of food, inasmuch as in practically all of the experiments the subjects indulged in more or less muscular activity, and in relatively few cases were there controlled periods of fasting; furthermore, only the carbon-dioxide production was determined. As a result of the comparison of the data obtained in the evening experiments and experiments on the following morning, the authors concluded that the carbon-dioxide production in the morning experiments was about 14 per cent lower than that in the evening experiments.

Falloise And Dubois, 1896

Falloise and Dubois,2 collecting expired air in a rubber bag and analyzing the air by the Hempel method, made a number of fasting experiments 15 hours after food and obtained an average respiratory quotient of 0.71. In the food experiments, a mixed diet was first given and the respiratory quotient was studied every half hour for 3 hours after the meal. With this diet the respiratory quotient reached its highest point in 2 hours. Falloise and Dubois then studied the quotient 2 hours after a meal predominating in fat; abnormally low respiratory quotients were obtained. Two hours after the ingestion of 60 grams of glucose the authors found that the quotients tended to approach unity but never quite reached it, the average of 6 experiments 2 hours after 60 grams of glucose giving a quotient of 0.90. The oxygen consumption with a basal value of 4.85 c.c. per kilogram per minute rose to 5.16 c.c. 2 hours after a mixed diet, and to 4.4 c.c. and 4.6 c.c. in experiments 2 hours after a fat diet and 2 hours after 60 grams of glucose, respectively. The fact that the last two series of observations gave values lower than the basal value throws considerable doubt upon the accuracy of the experiments.

1Sonden and Tigerstedt, Skand. Arch. f. Physiol., 1895, 6, p. 1.

2Falloise and Dubois, Travaux du Lab. de L. Fredericq, 1893-95, 5, p. 147; Arch. de Biol., 1896, 14, p. 457.