The value of a food for an infant depends, in the broadest sense, on two factors: on the one hand, whether or not the food meets the requirements of the organism in furnishing sufficient energy and material for growth, and on the other, whether or not the food itself, or the substances derived from it in the process of digestion, exert any deleterious action on the organism.
Fundamentally associated with the first problem is the question of absorption of the food in the gastro-intestinal canal. In our system of infant feeding in which the percentage of protein, fat and carbohydrate in the food is the criterion by which we judge of its suitability, and by which we modify the mixture according to the clinical manifestations, it is important to know whether the absorption of the different substances is influenced by the percentage relation of one to another. Very few observations
CHARLES A. FIFE, BORDEN S. VEEDER. STUDIES IN THE METABOLISM OF ATROPHIC INFANTS. Am J Dis Child. 1911;II(1):19–29. doi:10.1001/archpedi.1911.04100070026003