Understanding Macronutrients

Updated: Mar 1, 2019

When we consume a certain food, we only see the food itself. However, our body only understands macronutrients: it doesn’t care what the food is, it only can differentiate between proteins, carbohydrates and fats. Those are the 3 macronutrients that compose every food.

In order to follow a balanced and healthy diet that will help you achieve your goals, when you feed yourself you need to focus on the amounts of protein, carbs and fats you are consuming, rather than just on the food itself. So in order to understand better each macronutrient and the roles they play in our body, today I’m to briefly talk about what they are and what roles they play.

Lets begin!!


They are our main energy source, our body’s fuel, and they also are part of our cell’s membranes and other minor structures. The energy they provide us with, is our primarily and main energy source.

There are different types of carbohydrates, but once we consume them our body breaks them down in, usually, glucose.

There are 3 that stand out:

The first one is starch. Polysaccharide made out of amylopectin and amylase, starch and the glucose units it is decomposed in by our body during digestion, are the main energy sources of human beings. You can find starch in seeds, potatoes, rice, cereals, etc.

The second one, maybe more famous than the previous one, is fiber. As we all know, it plays a crucial role during the digestive process, avoiding constipation, and helping in many other different ways: it helps keeping your gut healthy, it prevents biliary stones, etc. it is abundant in cereals, vegetables and fruits in general.

Last one, and the most controversial one, sugar. Considered as the 21stcentury’s drug, its essential function is to provide us with immediate energy. Due to its fast digestion, once we consume it, and in just around 15 – 20 mins, it is digested, it goes into our bloodstream and it is driven directly into our muscles. However, its consumption must be very controlled, since an excess of sugar can cause really serious health problems (cancer, arthrosis, osteoporosis, etc).


These are our bricks, proteins are what gives form to our body. Proteins are composed of carbon, hydrogen, oxygen and nitrogen, with other elements like sulfur, iron, phosphor and zinc. It is important to remember that protein is the only macronutrient that contains nitrogen, nonexistent in fats and carbs, being this one of the main reasons why it is so important for both, building new muscle tissue and keeping it (remember that a positive nitrogen balance implies an anabolic state, while a negative one implies a catabolic state).

They are an essential component for our cells and we need them to keep our metabolism active and keep our blood sugar levels under control.

Proteins play a lot of different functions: they stimulate growth, they create antibodies, help repairing damaged muscle tissue, they create new tissue and they are key for synthetizing different tissues of our body.


The third and last macronutrient is fats.

Just like the two previous ones, our body needs fats in order to be able to work correctly and to be able to carry out different internal functions and processes, such as providing us with energy, creating cell’s membranes, help building several hormones, etc. Also, I want to make something clear about fats: FATS ARE NOT THE ENEMY. If you think that “not eating fat = losing fat” you are absolutely wrong. But that’s something I’ll talk about on a future post ;)

Essentially, we can classify fats in 2 big groups depending on whether if they have double bonds in their molecules or not: saturated fats, without double bond, and unsaturated fats, with double bond (unsaturated fats are divided in monounsaturated fats and polyunsaturated fats).

We can call saturated fats “the bad” fats. Since they are already processed, our body does not transform it in any way, so it tends to be accumulated on our arterial walls, causing serious health problems. This type of fat can be easily spotted, since it is solid at room temperature, and it is present in animal foods like the fat in cold meats, chicken skin, etc.

Unsaturated fats, as I’ve already said, are divided in monounsaturated fats (with only one double bond) and polyunsaturated fats (with two or more double bonds).

Monounsaturated fats help lowering blood cholesterol levels and help preventing coronary diseases, amongst many other functions. They can be found in nuts, avocado, olive oil and fatty fish, for example.

Polyunsaturated fats are essential, meaning that our body cannot manufacture them. We need to consume them, so our body can benefit from its properties.

There are 2 that stand out:

  • Omega 6 (linoleic acid or LA): helps controlling the triglycerides, lowers cholesterol, help keeping your immune system working correctly, they take part on the formation process of several hormones, etc.

  • Omega 3 (made out of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linoleic acid (ALA)): fluidics the blood, helps with hormones secretion, helps with several hormones’ creation, regulates your heart’s rhythm, it has anti-inflammatory and anticoagulant properties, etc.

That’s essentially, and in a very summarized way, what each macronutrient does in our body and what purpose it serves. They play many other roles, but we could write an entire book on each one. Our body needs them all three in order to work correctly, you just need to determine how much it needs and how much you are consuming.

That’s it for today’s post!! If you have any doubt, question, suggestion or constructive critic, please do not hesitate to let it in the comments section or using my social media.

Don’t forget to share the post!!

See you in the next one! :)


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