Here's why:

* Efficiency: Glucose is a readily available and easily metabolized fuel source. Our bodies have evolved to use glucose efficiently.

* Versatility: Glucose can be used by almost every cell in the body for various functions, including:

* ATP production: The primary energy currency of the body.

* Building blocks: Used for the synthesis of other essential molecules like amino acids and fats.

* Regulation: Blood glucose levels are tightly regulated by hormones like insulin and glucagon, ensuring a constant supply of energy.

While glucose is the preferred source, the body can also utilize other energy sources like fats and proteins when glucose is limited.