Energy balance is based on the principle that no energy can be created out of nothing and no existing energy can be extinguished. When this principle is adapted to biological systems, it can be considered that the energy outsourced from nutrients, basal metabolism, the energy consumed through physical activities, and the thermogenic effect of nutrients are well-balanced.
Basal metabolism refers to the minimum energy needed for the continuity of vital body functions.
The energy consumed by physical activity constitutes the most flexible part of daily energy consumption. It includes the energy consumed by routine physical activities as well as sports activities. It is called PAL (Physical activity level).
The energy needed during the ingestion, digestion and processing of foods is referred to as thermogenic effect of foods. It constitutes approximately 10-15% of the daily consumed energy.
The physical activity levels for children and adolescents and daily amounts of energy required according to age and gender are shown in the chart. Considering this need while planning the diet is crucial for continuous growth and development in children.
If the energy taken is more than the energy consumed, it is stored and called a positive energy balance. While linear growth and weight gain are observed with positive energy balance during childhood, lack of linear growth in adults results in weight gain.