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