Explain how fat can provide both energy and protein to the organnism

The body uses three main nutrients to function 

carbohydrate, protein, and fat.

These nutrients are digested into simpler compounds. Carbohydrates are used for energy (glucose). Fats are used for energy after they are broken into fatty acids. Protein can also be used for energy, but the first job is to help with making hormones, muscle, and other proteins.