wtorek, 6 stycznia 2015

What is metabolism

Before we start to talk about issues that are strictly connected with a diet, we should make sure we know a few basic definitions connected with  metabolism.

Metabolism  is the set of life-sustaining chemical transformations within the cells of living organisms. Sounds complicated? Basically, it is all about composition and decomposition, production and use of energy.

Metabolism is usually divided into two categories: anabolism and catabolism.

Anabolism is a set of processes of producing complex chemicals from basic ones. The organism must be supplied with energy, to start anabolic processes. Imagine building a wall, then a house from individual bricks. Here also the energy is essential, the energy in the form of bricklayer’s work. Nothing will happen by itself- this is what anabolism is all about. That is the way in which particular tissues and organs are developed in our organisms. An example of this is the synthesis of structural proteins, then muscles from individual amino acids that were delivered to the organism with food.

The second category of metabolism is catabolism. Catabolism is the process of breaking macromolecules into their smaller units. This is similar to bulldozing an old house- thanks to that we get bricks which we can reuse in building a new house. The process of catabolism releases energy. An example of catabolism is breaking proteins into single amino acids which are then used in anabolic processes to build structural proteins and finally to build muscles.

There are three macro- elements which supply our organisms with energy, namely proteins, fats and carbohydrates. Of course, they are not only our suppliers of energy, they have many other important functions about which you will read in the next articles. Carbohydrates break into simple sugars for example glucose and fructose. Fats break into fatty acids and glycerol and proteins break into amino acids. And this is our catabolism. This single molecules will be used by our organisms to build other structures in anabolic processes. Now we are getting to the heart of the matter: we eat to supply our organism with energy which is essential to sustain all processes in our body.

How much energy should we provide?  

Total energy expenditure gives us information  of total consumption of energy by our organisms. Total energy expenditure comprises basal metabolism and  metabolism that is connected with the entirety of physical activity (physical work and headwork, digestion, sport, walking, household activities etc.) The issues of TEE and BE and estimating your energy expenditures will be discussed in the next article.

 Photos come from www.foter.com

MA Rafał Bytomski
MA Anna Spalik-Bytomska