Glucose paradox

Glucose paradox is a theory formulated by biochemist Dr. J. D. McGarry and his research associates. It is a theory that demonstrates the importance of lactic acid in carbohydrate metabolism. The paradox is that the large amount of glycogen (10%) in the liver cannot be explained by its relatively minimal glucose absorption.

After the digestion of carbohydrates and their entering into the circulatory system in the form of glucose (blood sugar), some glucose rather than going directly to the liver and being converted into glycogen, will be absorbed directly into the muscle tissue and convert into lactic acid in the anaerobic energy system. This is true especially in situations of energy depletion and exercise.

The lactic acid is then taken to and converted by the liver into the building blocks for liver glycogen. Much of the body's liver glycogen is produced indirectly from lactic acid rather than directly from glucose in the blood.

References

*10 THINGS YOU SHOULD KNOW ABOUT LACTIC ACID: OLD MYTHS AND NEW REALITIES, by Thomas Fahey, Ed.D., Professor of Exercise Physiology, California State University at Chico
*BRASS C.A., CRAWFORD J.M., NARCISO J., GOLLAN J.L.. (1992) Hypoxic liver injury and the ameliorating effects of fructose: the 'glucose paradox' revisited. Am. J. Physiol. 263: G293–300.