The human body converts the food it consumes into energy in order to function and stay alive. This energy supply enables the body to do a number of things vital to its survival, including:
An individual who does not perform in any physical activity will still require roughly 1,200 calories a day in order to maintain their body’s essential functions.
These essential functions include: the heartbeat, metabolism of foods, respiration and regulation of water and body temperature.
Physical activity includes all forms of movement so the vast majority of individuals will perform some sort of physical activity each day.
The more active an individual is the more energy they will require.
Every individual will require some degree of tissue repair but more energy will be needed during periods of growth in which new tissues are formed. This includes the life stages of infancy, childhood and adolescence due to an increase in body size.
During pregnancy, particularly in the second and third trimesters, more foetal growth occurs so more energy is required. After birth, there is a higher energy demand placed on the body during lactation, as the production of breast milk is energy intensive.