The fasting subject has elevated ketones,1-3 elevated nonesterified fatty acids ( NEFA),4,5 negative nitrogen balance,6,7 lowered blood suger,6 salt loss,7,8 water loss, and weight loss.6,8-10 In the fasting man, the glycogen reserves6,11 are soon depleted, and fat and protein fcatabolism supplies the body's caloric needs since new carbohydrate is only available in minimal amount.Thus, at a cellular level, the major characteristic of fasting is limitation of available carbohydrate as an energy source.12 Since fat and protein are the energy sources in fasting, there should be little difference in cellular metabolism whether the fat and protein come from endogenous or exogenous sources. This study was undertaken to determine the metabolic effects of an exogenous caloric mixture of constituents similar to the endogenous caloric mixture of fasting.
The subjects in this study were normal healthy volunteers placed on a diet of normal
AZAR GJ, BLOOM WL. Similarities of Carbohydrate Deficiency and Fasting: II. Ketones, Nonesterified Fatty Acids, and Nitrogen Excretion. Arch Intern Med. 1963;112(3):338–343. doi:10.1001/archinte.1963.03860030092007
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