Nutrition in everyday practice.

Date:
1939
Catalogue details

Licence: In copyright

Credit: Nutrition in everyday practice. Source: Wellcome Collection.

    16/100 (page 10)
    THE NUTRITIONAL SIGNIFICANCE OF FAT* By R. G. Sinclair Kingston, Ont. III. Fat as a Source of Energy Weight for weight, the fats are a much richer source of energy than either the proteins or carbohydrates. This is due to several factors: the higher percentage of carbon and hydrogen; the rela¬ tively “dry” state of fat as compared with the high water content of the carbohydrates and proteins as they are ordinarily eaten; and the more complete digestibility of fat than of crude carbohydrates and proteins. The superiority of fats in this respect is of consider¬ able practical importance. Man is by nature an omnivorous creature, and, as has been pointed out by Starling, the human alimentary tract is best suited to the digestion of relatively con¬ centrated foodstuffs in which fat makes up 20 to 25 per cent of the energy content. Provided the energy requirement is moderate, a man can get along quite well on a very low fat diet. Indeed an experiment has recently been reported in which a man maintained himself for six months on a diet which provided only about 2 grams of fat per day. Subjectively, “the most noticeable feature was the marked absence of fatigue.” However, in this case the diet used was specially selected and consisted mainly of skimmed milk, sugar and starch. If, on the other hand, one is forced to get along on a low fat diet, consisting mainly of the usual crude high carbo¬ hydrate foods, such as the cereals, and especially if required to do hard manual labour, then the observations are quite different. Based on the experiences in Britain and the central European countries during the World War, when fat consumption was greatly restricted, the low fat diets resulted in premature hunger, a reduced capacity to do sustained work, and in general a reduction in the energy intake below the usual maintenance level. It has been claimed that a high carbohydrate diet low in fat leads to excessive fermentation in the intestinal tract with resultant discomfort and disability. There is considerable difference of opinion as to the optimum level of fat intake. For the average adult, about one-third of the calories seems to be a suitable level. However, it depends a good *Departmen.t of Biochemistry, Queen’s University, Kingston, Ont.