Question

Compare the potential energy stored in lipids, proteins and carbohydrates. How are these substances utilized by the body, in which order does the body look for these molecules as a source of energy.

Answer 1

The potential energy stored in lipids is 9 calories per gram
The potential energy stored in proteins is 4 calories per gram
The potential energy stored in carbohydrates is 4 calories per gram

This is how they are utilized by the body: 

Lipids are broken down into their most basic form, glycerolProteins are broken down into their most basic form, amino acidsCarbohydrates are broken down into their most basic form, sugars

The body then utilizes sugars, amino acids and glycerols to build substances that are needed for its growth, maintenance, and activity.

The body looks for these molecules as a source of energy in this order:
1. Carbohydrates
2. Lipids
3. Proteins