Food is necessary to provide the body with energy. The SI unit of energy is the joule (J), and 1 kJ = 0.239 kcal. The conversion factor of 4.2 kJ, equivalent to 1 kcal, is used in clinical nutrition.
Energy balance is the difference between energy intake and energy expenditure. Weight gain or loss is a simple, but accurate, way of indicating differences in energy balance.
There are two approaches to assessing energy requirements for subjects who are weight stable and close to energy balance:
- assessment of energy intake
- assessment of total energy expenditure.
This can be estimated from dietary surveys and in the past has been used to decide daily energy requirements. However, measurement of energy expenditure gives a more accurate assessment of requirements.
Basal Metabolic Rate
Recommended healthy diet
Energy Stores - Protein, Carbohydrate, Fat