Macronutrients: what they are, types and functions in the human body

macronutrients they are one of the most important concepts in the world of health and nutrition. Let’s see how they are, what their types are and how they influence the functioning of our body.

    What are macronutrients and how important are they?

    From a nutritional point of view, macronutrients are the compounds that provide most of the body’s metabolic energy. These are the carbohydrates, fats and proteins.

    We must keep in mind that we are dealing with a purely utilitarian group, because despite all these nutrients composed of molecules of an organic nature, they have little to do with each other beyond the energy intake that they represent for man.

    However, like all classification criteria, this way of grouping foods is of immense utility in the field of nutrition. If you want to know the peculiarities of each of the macronutrients and what role they play in our physiological well-being, stay with us

    The terminology conglomerate concerning food and health is increasingly present in the general population and this is no wonder, because the World Health Organization estimated that in 2010, 20% of the adult population and 10% of children suffered from some type of obesity-related disorder. In 2016, these figures reached over 650 million people.

    Therefore, it is not uncommon to know that heart disease is the leading cause of death in high income countries. This type of information is not just anecdotal, as it highlights the need to know in depth the distribution of calories in our diet, what to eat and what to limit. Again, it is not a question of forbidding but of knowing, because few foods are really harmful. As they say, control is the key.

    Types of macronutrients

    Once the importance of food knowledge has been defined by the general population, it’s time to immerse yourself in the world of macronutrients. Keep reading, as we painstakingly dissect each of the clusters with data and statistics of great interest.

    1. Carbohydrates

    Carbohydrates or carbohydrates they bring together a series of biomolecules composed mainly of carbon, hydrogen and oxygen. It should be noted that these macronutrients are the main source of energy for humans, as they are the fuel for 50 to 80% of the daily metabolic expenditure of a relatively active person.

    In addition to being an excellent source of immediate energy, carbohydrates they are an integral part of our physiology and our genes: Our species has about 10 grams of carbohydrate per kilogram of tissue, and the pentoses that give rise to each of the nucleotides in our RNA and DNA strands are simple carbohydrates.

    We can divide carbohydrates into monosaccharides, disaccharides, oligosaccharides, and polysaccharides based on their chemical structure. We don’t want to make this space a complex lesson either, so we’ll limit ourselves to saying that monosaccharides are the simplest molecules and polysaccharides the most complex, the latter being formed by chains of more than 10 monosaccharides.

    Special mention is required for monosaccharides and disaccharides considered as free sugarsAs of course, they are the most controversial group within carbohydrates. Here we find galactose, fructose or glucose among others, which are generally found in fruits or which are added artificially in sweet products.

    The World Health Organization recommends that only 5% of daily nutritional energy comes from these sources, as they have been shown to have oxidative activity that promotes cellular aging, among other, more immediate effects such as the formation of cavities.

    On the other hand, the rest of the carbohydrates such as starch (a polysaccharide) are excellent nutritional elements. It is found, for example, in potatoes, rice, corn, grains and fruits. We must keep in mind that carbohydrates make up the majority of the dry weight of plant matter, so we are faced with the most abundant nutrient on Earth.

      2. Proteins

      In the next group we have proteins, a series of linear macromolecules formed by chains of amino acids. From a nutritional point of view, it is estimated that they should not represent more than 15% of the daily calorie intake of the individual. In most Western countries, meat is the most consumed source of protein, because together with milk and some grains, it accounts for 75% of the protein consumed in the diet.

      Beyond what many people believe, protein is not a macromolecule only linked to the animal kingdom, as vegetables like lentils, chickpeas and many produce them as well. In recent years, products such as red and processed meats (such as burgers or sausages) have been in the spotlight, as they have been classified as “potentially carcinogenic” and “carcinogenic” respectively. What does it mean?

      It has been observed that consuming 50 grams of processed meat per day increases the risk of colorectal cancer by about 18%, so they have been classified as confirmed carcinogenic compounds. This is due to the fact that during its production harmful compounds such as N-nitrous and polycyclic aromatic hydrocarbons are formed. Red meats do not show such a clear direct correlation with carcinogenic processes, but it is suspected nonetheless that they may promote them as well.

      However, proteins are necessary for the development of tissues, the maintenance and repair of the body, the production of enzymes and many other vital processes, so we cannot reject their consumption in any way. As a result, alternative protein sources to red or processed meat, such as chicken, turkey, tuna, and a diverse group of legumes that can be delicately combined in the diet, are increasingly on the increase.

      3. Fats

      Finally, we have the bold group, a generic term which designates several classes of lipids, a series of organic molecules made up mainly of carbon and hydrogen. Surprising as it may sound, nutrition experts recommend that 20-30% of daily calories come from fat, which is more than protein.

      For much of the general population, the term “fat” refers to tissues of animal tissues, but we are faced with a misconception. Unsaturated fats are positive for the human body because they are an excellent source of energy and are found naturally in vegetable oils, nuts, fish like salmon or trout, and dairy products like yogurt or cheese.

      The problem comes when we approach the area of ​​unsaturated or trans fats, that is, those found in cakes, fries and other ultra-processed foods. Fat intake must be balanced and of natural originAs these types of processed foods are clearly associated with heart disease and other illnesses.

      It is not uncommon for the United States to break obesity records every year, as over 36% of a person’s calorie intake in this country is from fat, most of it of an unsaturated nature. On the other side of the coin, we have several countries in the South, where daily fat intake rarely exceeds 8-10% of total metabolic needs. Therefore, we are not surprised to know that more than 821 million people suffer from hunger.


      These last lines launched a key idea that we want to highlight: none of the macronutrients are bad if taken in the right amounts. Even the most dubious terms of fame such as fat can be essential for the body’s diet and metabolic expenditure. In general, we can say that more than half of the energy obtained in the diet must come from carbohydrates like starch. (still limiting free sugars), about 15% must come from animal or vegetable proteins, and 20 to 30% from fat remaining, mainly unsaturated of natural origin.

      This also does not mean that we should strongly reject processed meats for their carcinogenic potential or ultra-processed foods because of the “empty calories” they entail. Emotional well-being is as important as physical well-being, which is why becoming a slave to dietary numbers is never a good idea: in control is key.

      Bibliographical references:

      • Distribution of macronutrients and food sources in the Spanish population: results obtained from the scientific study ANIBES. Retrieved October 11 from
      • World hunger continues to rise, warns a new report from the UN, the World Health Organization (WHO). Retrieved October 11, from—new-un-report-says.
      • Macronutrients: Carbohydrates, Fats and Proteins, Collected October 11 at,de%20almidones%20y%20diversos%20az% C3% Bacares.
      • Obesity and overweight, WHO. Retrieved October 11, from
      • Reduce consumption of free sugar in adults to reduce the risk of noncommunicable diseases, WHO. Retrieved October 11, from

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