Proteins: These are major macromolecules that are formed of polypeptide chains.
There are mainly three biological molecules or biomolecules which give energy, they are fats, carbohydrates, and proteins.
Fats produce or yield more energy than other biomolecules.
Carbohydrates are used for energy because they are a quick energy source, especially glucose, and they easily break down in the body. Starch is used as a stored energy source.
Food calorimetry is used to measure energy content from a food
Proteins and most carbohydrates have the same energy content. Fats have more energy content.
Proteins and most carbohydrates yield 4 calories per gram whereas fats provide 9 calories per gram.