RT Journal
T1 FOod and metabolism
JF Journal of the American Medical Association
JO Journal of the American Medical Association
YR 1919
FD March 15
VO 72
IS 11
SP 799
OP 800
DO 10.1001/jama.1919.02610110031012
UL http://dx.doi.org/10.1001/jama.1919.02610110031012
AB It is becoming a common experience in these days to speak of food in terms of calories rather than ounces, and to make comparisons between different nutrient substances on the basis of their so-called energy or fuel values. The ordinary student of nutrition, as well as the casual reader of dietetic literature, is more than likely to gain the impression that, calory for calory, most foods are interchangeable so far as their nutritive value is concerned. The inadequacy of such a conclusion has repeatedly been emphasized in these columns. The food calorimeter gives no indication of the factor of digestibility, for example, without which concentrated calories are quite as worthless for human physiologic purposes as is a piece of anthracite coal. There is, furthermore, a growing realization of the inadequacy of the hypothesis of the "isodynamic replacement" or equivalence of foods which was so generally taught a few years ago.