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.
This is due to the 10% Rule. The 10% Rule states that on average 90% of energy stays at its current level while 10% is passed down when the holder of the energy is consumed.
