Observations on the Respiratory Quotients and Weight Gain of Man after Eating Large Quantities of Carbohydrate.

The glycogen in the liver cannot rise above 15 % and it is stated in textbooks that the capacity of muscle to store glycogen is limited. It would be considered unlikely that this total store could be more than doubled. Hence, if an individual consumed 400 g of carbohydrate in excess of his energy requirements, then it would be expected that there would be a net conversion of carbohydrate into fat. As carbohydrate molecules contain more oxygen relative to carbon and hydrogen than do molecules of fatty acid, this conversion has a high respiratory quotient (RQ). RQS well above 1.0 have been recorded in animals which are laying down fat. The classical example is the marmot. Pembrey (1902) records RQS of 1-4 in these animals when preparing for hibernation. The conversion of carbohydrate into fat after a dietary carbohydrate excess should be easy to demonstrate in man by measuring the RQ and finding values of 1.0 or above. This paper records measurements under such conditions and also observations on the changes in weight of some of the subjects. I t will be shown that, in fact, it is difficult to raise the RQ of man to 1.0, even when the subject undergoes real discomfort from his enforced gluttony. Possible explanations of the apparently low RQ after excess carbohydrate are discussed. A preliminary account of some of these experiments has already been given (Passmore & Swindells, 1962).