T H E C U B A R E V I E W 27 



SUGAR AND ITS VALUE AS FOOD 



By Mary Hiiiman Abel, from "Farmers' Bulletin 535," U. S. Df-pt. of Ai/rimliure. 



(Continuation) 



SUGAR AS A FOOD FOR MUSCULAR WORK 



Food must supply enough protein or nitrogenous material for the formation and repair of 

 tissues and for certain other uses in the body, and in addition sufTujient other material to make 

 up the amount of energy necessary for heat and muscular work. The nitrogen-free nutrients 

 are fats and carbohydrates. In the ordinary diet the relative amount of fat and carbohydrates 

 is usually regulated by personal preference. Fat -will furnish two and one-fourth times as much 

 energy per pound as carbohydrates. Taking account of this fact it is immaterial on chemical 

 grounds which of these nutrients supplies the necessary energy, although this is not the case 

 from the standpoint of hygiene. 



The main function of sugar as found in the blood, whether resulting from the digestion 

 of sugar or of starch, is believed to be the production of energy for internal and external muscu- 

 lar work, and, as a necessary accompaniment, body heat. This has been amply demonstrated 

 by experiment. By ingenious devices the blood going to and from a muscle of a living animal 

 may be analyzed, and it is thus shown that more blood traverses an active or working muscle 

 and more sugar disappears from it than is the case with a muscle at rest. 



To decide the question of the value of .sugar as a source of energy for the working muscle, 

 much careful laboratory work has been carried on. It has been found that an increase in the 

 sugar content of the diet, when not too great and when the sugar is not too concentrated, 

 lessens or delays fatigue and increases working power. Increased amounts of sugar were found 

 to increase the ability to perform muscular work to such an extent that on a ration of 500 grams 

 (17.5 ounces) of sugar alone a man was able to do 61 to 76 per cent more work than on a fasting 

 diet, or almost as much as on a full ordinary diet. The addition of about half this quantity of 

 sugar to an ordinary or to a meager diet also considerably increased the capacity for work, the 

 effect of the sugar being felt about a half hour after eating it, and its maximum effect showang 

 itself about two hours after eating. The coming of fatigue was also found to be considerably 

 delayed on this diet, and taking 3 or 4 ounces of sugar a short time before the usual time for 

 the occurrence of fatigue prevented the appearance of it. Lemonade, or other .similar refresh- 

 ing drinks, and chocolate have been suggested as mediums for supphing in small doses an extra 

 amount of sugar to men called upon to perform extraordinary muscular labor. The application 

 of these results to the food of soldiers who may be called upon for extraordmary exertion in 

 marching or fighting is very evident. Practical tests of the value of sugar in preventing or 

 delaj-ing fatigue, made in both the German and French armies, indicate the value of sugar in 

 the ration when the men are subjected to great exertion. 



It is believed that more decisive results may be obtained by tests -nith men and animals 

 in which the effects of given quantities of sugar in the diet are compared vath those obtamed 

 with starch and other food materials. Such experiments have been made under the aaspices 

 of this department with men in the respiration calorimeter. This apparatus makes it possible 

 to measure with great accuracy the relation between the material consumed and the muscular 

 work done. In experiments planned to test the value of carbohydrate foods as a soiurce of 

 energj' during severe muscular w^ork, the subjects were able to include 350 grams, or about 

 three-quarters of a pound, of cane sugar in their daily diet without any deleterious eflfects.(j) 

 Accordmg to our present knowledge the value of sugar as a food for muscular work may 

 be briefly summarized as follows: 



When the organism is adapted to the digestion of starch, and there is sufficient time for 

 its utilization, sugar has no advantage over starch as a food for muscular work. 



In small quantities and in not too concentrated form sugar will take the place, practically 

 weight for weight, of starch as a food for muscular work, barring the difference in energy and 

 in time required to digest them, sugar having the advantage in these re.spects. 



It furnishes the needed carbohydrate material to organisms that have little or no power 

 j U. S. Dept. Agr., Office Expts., Stas. Bui. 175. 



