INFLUENCE OF PREVIOUS DIET ON METABOLISM DURING FASTING

Abstract

The ability of the rat, previously force-fed a high fat diet for 6 weeks, to survive longer during fasting than similarly treated animals previously maintained on a high carbohydrate regime, appears to be related to the capacity of the former prepn. to continue burning mainly fat for energy during the fasting period, thus sparing carbohydrate and protein stores. This was evidenced by an enhanced excretion of acetone bodies in the fat-fed group, a slower disappearance of blood sugar, and a lowered rate of nitrogen excretion after initiation of the fast. On the other hand, the apparent rapid depletion of carbohydrate stores in the carbohydrate-fed animal after the deprivation of food, as indicated by the rapid early decline in blood sugar, was followed by increased utilization of protein for energy. It may be deduced that the earlier death of the animals in the latter group was associated with a more rapid depletion of body protein to the point where there were no longer sufficient quantities of this substance available to satisfy the minimal requirements of the organism.