Now that the good weather is getting closer some of you might be thinking of starting a diet, and advertisements of weight loss supplements are all over the place. So, one of the words you may hear more often during the following months is “metabolism”. But, what does metabolism really mean?
Metabolism
is everything that happens inside our cells that allows us to get energy from food and use it in our daily lives, either to repair tissues, create heat or go for a walk.
Metabolism is a set of chemical reactions that are divided into 2, catabolism and anabolism.
Catabolism
is the process through which energy is obtained by breaking food down. Energy in food comes from macronutrients, that is, carbohydrates, proteins and fat. In case you are curious, carbohydrates and proteins have 4 kcal in each gram, and fat has 9 kcal per gram. Vitamins and minerals don’t have energy.
By the way, alcohol has almost the same amount of calories as fat, 7 per gram.
Anabolism
uses energy to build up structures from small molecules, for example, to repair or create new cells.
Imagine a Lego. Food is made up of small pieces (nutrients), that, when they split, release energy (catabolism), which is stored basically in a molecule, adenosine triphosphate (ATP). These smaller pieces that form nutrients can link together creating bigger pieces, and for that, they need energy (anabolism).
Then, vitamins and minerals are not important? On the contrary! These micronutrients change their chemical structure to make possible metabolism reactions.
Imagine the cell as a factory. Carbohydrates, fat and proteins go through different machines that break them down to obtain energy or bind the pieces together to create new things. Well, vitamins are like forklifts that carry those pieces from one machine to another and minerals make up those machines.
And what happens if we don’t use all the energy we get from food? That the body accumulates it, that is, you gain weight.
And if you eat less than you need? Well, you lose weight.
Metabolism in our body varies a lot depending on the person: weight, height, age, and other factors such as physical activity or hormone levels.
Both catabolism and anabolism happen thanks to a lot of chemical reactions in our body that are regulated by many hormones. Probably, the one you might hear more often is insulin. Other examples are cortisol or hormones produced by the thyroid gland. Both processes are controlled by our body to maintain a balance between the 2 of them.
But, to get energy from food, eating is not enough, we need to breathe. Very important chemical reactions within metabolism happen thanks to oxygen and others produce carbon dioxide (CO2), which we get rid of through our lungs.
Besides, one of the metabolism products is water, which excess is also necessary to throw out.
If you have made it this far, many of you may be wondering: what about those supplements advertised to boost your metabolism and make you use more energy making you lose weight? Like the ones containing coffee or tea extracts or exotic fruits.
Well, here 3 things can happen. Either they are a fraud, or they boost your metabolism, but not enough to feel any effect, or they have side effects raising your body temperature, causing headaches, sleeping problems or raising your blood pressure and, therefore, they can be dangerous.
