Here's why:

* Carbohydrates are broken down into glucose: This is the primary fuel source for our cells and is used for a wide range of bodily functions, including energy production, brain function, and muscle contraction.

* They provide the most calories per gram: Carbohydrates provide 4 calories per gram, compared to 4 calories per gram for protein and 9 calories per gram for fat.

* They are readily available: Carbohydrates are found in a wide variety of foods, including grains, fruits, vegetables, and dairy products.

While fats and proteins also provide energy, they are not the primary source. Fats are primarily used for long-term energy storage and insulation, while proteins are essential for building and repairing tissues.