Why need to eat?

Food provides us with the energy and nutrients that we need to keep the body healthy and active. Nearly every process in the body is energy-dependent – so it’s essential we have a constant supply of energy.

The four main reasons we need to eat are:

(1) Development, growth and repair

The body needs energy to grow, primarily during childhood and adolescence – but this doesn’t mean that as adults we no longer need energy for growth. Tissues are constantly being repaired (replaced) even if they are not growing, and we need energy to fuel these essential processes.

(2) Body function

Even when we are at rest we still need a lot of energy. Maintaining the body’s normal physiological processes is very energy ‘expensive’, accounting for 60–75% of the body’s total energy expenditure. We need this energy for all those processes that we don’t normally think about, such as breathing, blinking, digestion, controlling body temperature and blood circulation.

(3) Physical activities

On average, 15–30% of total energy expenditure is on physical ‘work’. We need the energy from food to be able to move around and to participate in sports and other activities. The exact amount expended will depend on how vigorous the activity is and for how long it is performed.

(4) Supply of nutrients

Nutrients, such as vitamins and minerals play a vital role in converting other food sources into energy. They are also essential in helping to keep the body healthy and in good working order, aiding the healing process by enabling damaged tissue to be repaired quickly and effectively.