Here's why:

* Glucose is a simple sugar that our bodies can easily break down and use for energy.

* It's readily available from the food we eat, particularly carbohydrates.

* It's the main fuel source for the brain, red blood cells, and other tissues.

While other sources of energy exist, like fats and proteins, they are not as readily used as glucose by the body.

Here's a quick breakdown:

* Carbohydrates: Broken down into glucose, the primary source of energy.

* Fats: Used for energy storage and can be broken down into usable energy when glucose is limited.

* Proteins: Primarily used for building and repairing tissues, but can be used for energy in extreme cases.

So, while our bodies can utilize other energy sources, glucose remains the most readily available and efficient fuel source for our cells.