Red blood cells are entirely dependent on glucose as their only energy source. Glucose is utilized in glycolysis to produce the ATP output required by the red blood cell because red blood cells lack mitochondria, which would metabolize pyruvate to CO2 in other cells. The glycolytic output of energy from glucose breaking down to two lactates will produce two ATPs only because the NADH produced from the glyceraldehyde 3-phosphate dehydrogenase step of glycolysis will be consumed in the conversion of two 2-pyruvates to two lactates.

Check out the original short on glucose and red blood cells below:

https://youtube.com/shorts/nbEF42DaAko?feature=share