Why does our body need Energy?

Energy is usually defined as the capacity and power to do some work or some task. And certainly, our body uses energy for many tasks and functions, such as breathing, maintaining healthy cells and tissues, exercising, reading, studying, working, etc. All the processes that take place in our organism and all our external activities require energy to be carried out.

The energy we need to live is obtained mainly through food. This energy is used by our body to perform all its functions. Therefore, our energy needs will be satisfied if our food is adequate.

We must maintain a balance between the energy we get and the energy we spend. This is known as energy balance. When a person ingests less energy than necessary, the reserves of fat and, in some cases, muscle, are reduced; this causes an excessive weight loss and also muscle mass loss. On the other hand, when a person ingests more energy than necessary, the surplus energy is converted into fat and is stored as adipose tissue and, consequently, the weight is increased and the person becomes obese.

In order to calculate the energy requirement of a person, different aspects must be considered such as sex, age, height, climate, physical activity that the person develops, type of work he or she performs, etc. For example, an athlete needs more energy than a clerk, because his physical activity is greater and, therefore, he has a higher energy expenditure.

Some of the reasons we need energy are:

• To perform physical activities.
• To have a correct functioning of our body.
• To avoid fatigue.
• To think and to be focused.
• To have a good mental and physical performance.
• To strengthen our immune system.

    There are basically three metabolic pathways through which our body gets energy. These are known as Energy Systems:

The Phosphagen System: This system consists of ATP (Adenosine Triphosphate) and PCr (Phosphocreatine) that are stored in minimal amounts in muscle cells, which use ATP directly to obtain other forms of energy.

The Anaerobic System: In this system, the partial decomposition of the glucose provides the necessary energy with which the ATP is elaborated. The importance of this system lies in the fact that it has the capacity to quickly supply energy in the form of ATP.

The Aerobic System: It supplies ATP through the complete degradation of glucose and also using other different fuels such as lipids and, to a lesser extent, proteins. This process involves the consumption of oxygen and constitutes the main form of production of ATP.

Physical training influences energy metabolism, as it helps our body to make better use of oxygen and nutrients.

Dietary supplements based on vitamins, minerals, proteins, amino acids, etc., can help provide energy to our body and improve our performance, but in no case they can replace a balanced diet.