Proteins, fats and carbohydrates

Proper nutrition is a complex science about food and its effects on health. Nutrients that the body itself cannot synthesize should come from food. Among the nutrients necessary for normal life, include:

  • vitamins;
  • minerals;
  • amino acids;
  • fatty acid.

Some of these substances (micronutrients) the body needs in very small quantities, others, on the contrary, more (macronutrients). The lack of any of the nutrients often causes the development of serious diseases. Excess often leads to obesity and side problems.

Macronutrients: Basic Information

Macronutrients, or macronutrients, are nutrients that provide the body with the necessary energy and calories. They are necessary for normal growth, metabolism and maintenance of body functions.

Already from the name, it becomes clear: macronutrients are a group of substances necessary for a person in large quantities. Among the macronutrients belong: proteins, fats, carbohydrates.

Many are puzzled by the question of what should be the percentage of these substances in the daily diet and how many grams of each element should be received daily. But to answer it, it is important to understand what these elements are and what functions they perform.

These three classes of macronutrients are complex groups, each of which consists of many components. You can eat the same amount (in grams) of proteins, lipids and carbohydrates every day, but at the same time provide the body with different microelements each time, depending on the content of substances.

For example, in identical servings of olive oil and lard, lipids are drastically different. Therefore, it is important to maintain a balanced diet and a varied diet in order to maintain harmony in the body. And immediately the first conclusion: it is important not so much the amount of consumption of useful micro and macro elements (although this is also an important nuance), but their quality.

But when it comes to calorie supply, it’s still worth remembering that the energy value in 1 grams:

  • carbohydrate – 4 calories;
  • proteins – 4 calories;
  • fat – 9 calories.

Carbohydrates – A Tasty Source of Energy

Carbohydrates are a combination of different molecules that provide approximately 45 percent of the energy for the body. True, some types of carbohydrates, such as fiber and resistant starches, do not serve as a source of energy, but at the same time play an equally important role:

  • strengthen the health of the digestive system;
  • promote easy digestion of food and absorption of nutrients;
  • rid of toxins and toxins.

Functions in the body

Carbohydrates obtained from food are broken down into glucose and other monosaccharides. They increase the level of sugar in the plasma, supply a person with energy. The role of most carbohydrates is that they:

  • are an excellent source of nutrition;
  • all cells and tissues of the body use them for energy;
  • accumulate in liver cells and in muscle tissue in order to be activated if necessary;
  • necessary for the nervous system, brain, muscles (in particular, the heart), kidneys;
  • beneficial effect on maintaining intestinal health.

Carbohydrates are made up of carbon, hydrogen and oxygen. There are simple and complex carbohydrates.

Monosaccharides and disaccharides

Simple carbohydrates are made up of monosaccharides and disaccharides. They are able to quickly increase the level of glucose. Sweet in taste, quickly absorbed, providing the body with energy, and quickly disintegrate.

Monosaccharides are simple sugars, because they consist of one unit. In this form, they can be absorbed by the body. Unlike other carbohydrates, they do not require digestion during digestion. Therefore, monosaccharides from food quickly enter the blood, almost instantly increasing the amount of sugar in the plasma, immediately supply energy to the body.

Examples of monosaccharides: glucose, fructose, galactose. Simple sugars are found in varying amounts in foods from different categories. High content in ripe fruits and honey.

Monosaccharides are important sources of energy. But consuming large amounts of simple sugars without balancing with polysaccharides or oligosaccharides (which take longer to digest and therefore provide the body with long-term energy) can cause a significant increase in blood glucose followed by a sharp drop in the level.

As a result, at first there is a large and sharp release of energy, which is just as quickly replaced by a feeling of fatigue. Frequent repetition of such fluctuations can cause diabetes.


Disaccharides are combinations of 2 monosaccharides. To disaccharides belong:

  • lactose (milk sugar);
  • sucrose (table);
  • maltose;
  • isomaltose (sugar formed as a result of the breakdown of starch).

Disaccharides, like monosaccharides, give the food a sweet taste, and the body provides fast energy. Due to these biochemical properties, they are also referred to as simple sugars. In large quantities are presented in processed foods. Frequent consumption of disaccharides can also lead to an increase in blood glucose.

Because disaccharides contain 2 parts of sugar, they go through a decoupling process before being absorbed into the body. Therefore, for each disaccharide, the body has its own digestive enzyme. So, sucrase acts on sucrose, lactase – on lactose. The necessary enzymes are produced in the intestines. Assimilation of disaccharides proceeds quite easily. The exception is lactose.

There are people deprived of the lactase enzyme, which means that their bodies are not able to break lactose into 2 elements, which manifests itself in the so-called lactose intolerance. This means that the consumption of dairy products for such people is a problem. Lactose intolerance is more common in older adults.

Undigested milk sugar is not absorbed and contributes to the development of bacteria in the digestive tract that are unfavorable for the body. As a result, this leads to flatulence, heartburn and nausea. In addition, the acid produced by bacteria worsens the functioning of the intestine as a whole (reduces its ability to digest food), damages the cells of the digestive system. It is important for such people to refuse food, which contains lactose. Some studies show that lactobacillus supplements are beneficial for these digestive disorders.

Polysaccharides: starch, cellulose and resistant starch

Large carbohydrate molecules (such as fiber or starch) are a combination of several monosaccharides linked together. The composition of some of them may contain up to several hundred mono-sugars. Such a complex is called polysaccharides (from “poly” – a lot). The specificity of complex compounds is that they increase the level of glucose in the body more slowly, but act for a longer time. Complex carbohydrates are starches and fiber.

Plants store their energy by combining many mono-sugars. Such a complex can consist of hundreds (sometimes up to several thousand) glucose molecules. Plant products (such as seeds, which are supposed to provide strength to shoots) contain a lot of starch. When a young plant begins to grow, the starch is broken down into glucose and provides it with the energy it needs.


If a person eats starchy foods, such as corn or potatoes, the body uses polysaccharides from it in much the same way as plants. The digestion of starches requires more time than the process of processing disaccharides.

Therefore, we can say that starch is a sustainable source of energy. It does not cause a sharp saturation of the blood with sugar, the action of starch is a slow, consistent and long-term maintenance of strength in the body. And it is considered a good option for health.

The food presents 2 main types of starches:

  • amylose;
  • amylopectin.

Amylopectin is digested faster by the body. The process of absorption of food starches is preceded by the stage of splitting the substance into smaller elements – individual units of carbohydrates.

Cellulose (fiber)

Dietary cellulose, or fiber, is also a member of the polysaccharides, a family of complex carbohydrates. But in this substance, the sugar blocks are connected according to a slightly different principle, and the body cannot break the chains that bind them. Instead, the cellulose passes through the small and large intestines in its original form. Due to this quality, fiber performs important functions for the body:

  • accelerates the elimination of toxins and slags;
  • getting rid of constipation.

Useful cellulose is found in vegetables, grains, legumes. In particular, more fiber is found in unprocessed foods. For example, bran contains a lot of compounds, but already in flour it is not. Cellulose is also present in the skin of fruits, but is completely absent in drinks made from them.

Much has already been written about the benefits of fiber. Experiments prove the link between a diet based on a high content of fiber, and a reduction in the risk of developing oncological diseases, including in the intestine and mammary glands. Some researchers explain this by the ability of cellulose to remove toxins and toxins from the body, which contributes to healthy digestion.

Therefore, foods containing a lot of fiber should be included in diets for weight loss. Fiber maintains the normal state of the intestinal microflora, on which the body’s immunity depends. Cellulose deficiency in the diet causes constipation, increases the likelihood of hemorrhoids or colon cancer.

The beneficial effects of fiber:

  • reduces the possibility of developing cardiovascular diseases;
  • prevents the development of obesity;
  • reduces cholesterol.

Resistant starch

The last category of polysaccharides, or complex carbohydrates, is resistant starch. It got its name due to the fact that it cannot be processed in the small intestine. As a result, the compound acts more like cellulose than starch. Passing through the digestive tract and entering the large intestine, like fiber, it contributes to the production of beneficial bacteria in the intestines. Resistant starch is found in wild rice, barley, whole wheat, and buckwheat.

Among the representatives of sugars there are oligosaccharides. This is a cross between mono- and polysaccharides. Their structure can contain from 1 to 10 monosaccharides.

Energy sources

Sources of simple carbohydrates:

  • fruits and berries;
  • vegetables;
  • milk products;
  • sweeteners (sugar, honey, syrup);
  • candies;
  • soft drinks.

Source of complex carbohydrates:

  • bakery products;
  • cereals;
  • pasta;
  • rice;
  • beans;
  • peas;
  • starchy vegetables;
  • green pea;
  • corn.

Many of these products are also sources of fiber. Complex carbohydrates are in most vegetables, fruits, nuts, seeds, legumes, as well as whole grains.

What is the glycemic index

How quickly each type of sugar raises blood glucose is indicated by the glycemic index. Its range is a scale from 1 (the slowest effect on the body) to 100 (the fastest saturation, this indicator is equivalent to the speed of action of pure glucose).

Glycemic index table of some foods
pulsered lentils33
BreadWholemeal rye flour49
FlakesAll bran54
Dairy produceMilk, yogurt, ice cream34-38
Brown rice66
White rice72
Corn chips72
Oat cookies57
Potato chips56
Refined sugar64

Carbohydrates with a high glycemic index raise blood glucose fairly quickly. As a result, the amount of insulin in the blood increases, causing hypoglycemia and hunger. All this leads to the use of excess calories, which means excess weight.

Carbohydrates with a low glycemic index contribute to a slow increase in plasma glucose, which eliminates the sharp jumps in insulin production. Eating foods with lower GI reduces the risk of obesity, diabetes, or its complications.

Protein – the basis of everything

Proteins are an important component of the body, as they are part of the structure of most tissues, including bone and connective. The importance of proteins is already indicated by their name: “protein” from Greek means “in first place”.

Proteins are involved in almost most processes in the body, being enzymes. The body needs a constant replenishment of proteins that take the place of dead cells or damaged tissues. They also influence the growth and development of the organism. From 10 to 35% of the calories of the daily diet should come from protein foods.

The role of proteins:

  • contribute to the normal growth of children and adolescents;
  • essential for maintaining the health of pregnant women;
  • restore tissue;
  • strengthen the immune system;
  • provide the body with energy when there is not enough carbohydrates;
  • support muscle mass (promote muscle growth);
  • promote the production of hormones;
  • are enzymes.

How does the body benefit from proteins?

Proteins are broken down into peptides and amino acids. They are necessary for the growth and replacement of damaged or end-of-function tissue areas. But if the body does not get the calories it needs to live, protein can also be used as an energy source.

Of the 20 amino acids, 9 are essential. A person cannot synthesize them, so it is important to ensure the replenishment of these substances from food.

Protein Consumption Rates

The daily protein norm is determined on the basis of several parameters. One of them is the growth rate. That is, children in the period of active development need more proteins than adults.

Protein intake per day:

  • children up to 3 years old – 2,2 g per kilogram of weight;
  • from 3 to 5 years – 1,2 g per kilogram of weight;
  • adults – 0,8 g per kilogram of weight.

People who want to increase muscle mass also need an increased dose of protein.

Sources of protein:

  • seafood;
  • lean meat;
  • bird;
  • eggs;
  • beans;
  • peas;
  • soy products;
  • seeds;
  • dairy.

Proteins from plant foods, as a rule, contain less fat and cholesterol, supply the body with fiber and other essential nutrients.

Replenishment of protein in the body is achieved by providing the necessary amino acids.

Daily need for amino acids
NameChildren 4-6 months10-12 years oldAdults
Methionine and cysteine722413
Phenylalanine and tyrosine1202414
All essential amino acids (except histidine)71523186

What are amino acids?

Proteins are made up of smaller molecules (amino acids) linked together. The structure of the protein resembles beads strung on a chain. The activated protein takes on a slightly different shape – a three-dimensional structure (the chain twists and wraps around itself, forming a kind of ball). Like carbohydrates, amino acids are made up of carbon, hydrogen, and oxygen. But unlike them, they also contain nitrogen.

It is important that proteins come in different sizes. Some amino acid chains are quite short and consist of 50 elements, but most contain 200-400. Individual proteins can combine and form so-called protein complexes.

The largest protein complexes are bones, skin, nails, hair, teeth. They are made up of collagen, elastin and keratin. Collagen, for example, consists of 3 amino acids twisted into a long cylindrical chain. This chain binds to other collagen chains and creates thicker and stronger cylinders called fibrils. Fibrils can combine from 6 to 20 collagen chains, which means that they contain tens of thousands of amino acids. And this is the structure of only one, taken separately, protein.

A single amino acid resembles a simple carbohydrate – the body breaks down the protein structure to the state of an amino acid before absorption, following the principle of carbohydrate digestion. And only after that digests one small block at a time.

Where to look for amino acids?

A healthy person needs approximately 40-65 grams of various amino acids per day. If the body does not receive the required amount of protein, it begins to draw on reserves from its own muscles, destroying them. Insufficient intake of amino acids can cause stunted growth, poor muscle development, thin and brittle hair, skin diseases, a weakened immune system, and other troubles.

The source of amino acids are proteins from food of plant and animal origin. The most protein-rich foods: nuts, legumes, fish, meat and dairy products. In processed foods, the substance is sometimes presented in the form of a peptide – a hydrolyzed protein (consists of amino chains formed from 2-200 amino acids). Such foods are digested faster and easier to digest.

Essential Amino Acids

There are 20 varieties of amino acids and all of them are needed by the body, since each is involved in the creation of protein at a certain level. Half of them the body can synthesize on its own. However, the source of 9 of them is only food. They are called essential or essential amino acids. These include leucine, methionine, phenylalanine, tryptophan and others.

For the body, the correct ratio of amino acids to each other is important. Animal food, for example, contains amino acids in the same proportion as in the human body. Proteins from plant foods have a slightly different structure.

Many nutritionists are concerned that vegetarians, refusing meat, do not receive all the necessary proteins in full measure. Other researchers reject this theory. They suggested: since different plant foods contain different essential amino acids, then by eating a variety of foods (from whole grains, legumes, and other vegetables), it is realistic to get all the vital substances. In addition, some plant foods, such as soy, contain a protein that is similar in composition to proteins found in meat.

Fats and undeservedly bad reputation

Fats, or lipids, are perhaps the most complex macromolecules in food. There are many types of lipids.

Unfortunately, fats have gotten a bad rap, partly because excess calories are converted into body fat. The second reason is that saturated lipids, trans fats, cholesterol are the cause of many health problems (from cardiovascular disease to obesity).

However, the facts are that not all fats are bad. Most of them, on the contrary, are vital for the body. Therefore, when it comes to fats, you need to be able to distinguish between good and negative health effects, to understand what type of lipids can be obtained from a particular food.

According to nutritionists’ advice, the daily calorie intake per 25-35 percent should consist of healthy fats.

Role in the body:

  • promote normal growth and development;
  • serve as a source of energy;
  • essential for the absorption of fat-soluble vitamins;
  • are part of the building material for cells;
  • prevent damage to internal organs when walking, jumping, running, falling due to depreciation.

Fats, like other macromolecules, are made up of carbon, hydrogen, and oxygen. But the peculiarity of their structure is that they are insoluble in water. These are the so-called hydrophobic substances. Fats are broken down into fatty acids and glycerol. They are essential for tissue growth and hormone production.

Fat Types

By chemical properties, fats are saturated, monounsaturated and polyunsaturated.

Saturated lipids: “bad” fats, who are you?

Saturated lipids are made up of the right molecules. They retain their solid form at room temperature (except palm and coconut oils). Sources of such fats: butter and fats contained in meat.

More than 50 years ago, researchers started talking about the relationship between saturated fat and the rate of increase in blood cholesterol, which is the cause of atherosclerosis, cardiovascular disease. The food industry quickly responded to the scientists’ statement – products “low in fat” or “completely fat-free” appeared on the shelves of supermarkets.

Excessive intake of saturated fat and truth can adversely affect health. But the problem is that the fact concerning exclusively saturated fats has erroneously spread to other types of lipids needed by the body.

Saturated fats are found in large quantities in meat products, in particular in cuts with white solid fat. Minimizing your intake of saturated fat is a good idea. However, you can not refuse all lipids. It is important to take into account the fact that the brain is almost 60% composed of adipose tissue.

In addition, a diet low in all types of fat increases the risk of hormonal disorders, contributes to the development of cardiovascular diseases, and also reduces immunity and brain activity.

The importance of monounsaturated fats

Monounsaturated fats have attracted the attention of scientists after it was noticed that people who follow a Mediterranean diet are less likely to develop heart disease, cancer, and rheumatoid arthritis. Scientists explained this fact by the fact that the traditional Mediterranean diet contains a large amount of olive oil, rich in monounsaturated oleic fatty acid. In addition to olives, avocados, almonds, and cashews are rich in monounsaturated lipids.

Monounsaturated fats (for example, olive oil) at room temperature retain the structure of the liquid, but harden in the refrigerator.

Scientists continue to conduct experiments and prove their theory about the beneficial properties of monounsaturated fats. But no less actively study the functions of polyunsaturated lipids, in particular, omega-3 fatty acids.

Polyunsaturated substances

Polyunsaturated fats (PUFA) consist of molecules, the nature of the bonds between which is different from other lipids. This is the secret why they remain liquid at low temperatures.

There are many polyunsaturated fats. Most of them can be produced by a person independently, except for Omega-6 and Omega-3. And since these fatty acids are indispensable for people, it is important to replenish their stores of food.

Polyunsaturated lipids are present in large quantities in oils from grains and seeds (for example, linseed oil).

Essential Omega-3 and Omega-6

When it comes to lipids, one can not forget about the essential fatty acids – linoleic (Omega-6) and linolenic (Omega-3). They are necessary for the formation of biologically active lipids (eicosanoids), including prostaglandins, thromboxanes, prostacyclins and leukotrienes. Regular consumption of omega-3 fatty acids prevents the development of coronary heart disease.

The body’s need for essential fatty acids varies with age.

For adults:

  • linoleic acid – 2% of daily calories;
  • linolenic acid – 0,5% of total calories.

Linoleic acid, also known as Omega-6, is found in large quantities in oils from cereals, nuts, beans, sunflower seeds, sesame seeds, corn, soybeans, peanuts, pumpkin. Omega-6 deficiency is rare, as this fatty acid is present in many foods. In addition to those already mentioned, beef and poultry are good sources of linoleic acid.

The lack of omega-3 (linolenic acid) is associated with the development of diseases such as chronic inflammation (from intestinal processes to rheumatoid arthritis), cardiovascular disease, distraction and hyperactivity. Alpha-linolenic acid is found in large quantities in pumpkin, linseed, rapeseed, soybean oils, some leafy vegetables, but most of all in oily sea fish.

But it’s not enough just to consume omega-3 and omega-6 regularly. It is important to adhere to a certain ratio between these fatty acids. Nutritionists suggest the optimal ratio of omega-3 to omega-6 is 1:2. However, in practice, for many, this ratio is 1:25. To achieve a more beneficial ratio, it is important to reduce the amount of omega-6 in the diet and increase omega-3. This can be easily achieved by reducing the consumption of meat, dairy and refined foods. But at the same time, on the contrary, increase portions of fish (preferably salmon), flaxseed oil, walnuts, green leafy vegetables.

“Bad” Fats

Partial hydrogenation of unsaturated fatty acids (used in the food industry) leads to the formation of trans fats. They even at room temperature retain a solid or semi-solid texture. A high amount of trans fatty acids is found in cookies, cakes, crackers, chips. In cooking, this substance is used to extend the shelf life of confectionery. But trans fats lead to an increase in the level of cholesterol in the blood, which can later provoke the development of coronary heart disease.

One of the most important functions of lipids is that they are the main component of membranes in all cells of the human body. But different types of fats—unsaturated, monounsaturated, and polyunsaturated—are needed in different amounts. Cells primarily need polyunsaturated and partially monounsaturated types. They allow the membranes to remain flexible and mobile. When the level of saturated fat is too high, cell membranes become rigid, their functionality decreases, they lose the ability to protect the internal parts of cells, to pass chemicals dissolved in water through them.

Sources of lipids in foods

Monounsaturated fats:

  • olive oil;
  • peanut butter;
  • avocado;
  • seeds;
  • nuts.

Polyunsaturated fats:

  • corn oil;
  • soybean oil;
  • linseed oil;
  • oily fish;
  • walnuts;
  • some seeds.

Saturated Fat:

  • fat red meat;
  • dairy;
  • butter;
  • Palm oil;
  • Coconut oil;
  • cheese;
  • milk desserts.

Trans Fat:

  • margarine;
  • spread;
  • confectionery;
  • chips;
  • belyashi.

How the body uses proteins, carbohydrates and fats

The human body is an amazing machine, able to learn to survive on any kind of food, adapting to a variety of diets. This ability was inherited from his ancestors, in whom the frequency of food intake and diet depended on subjective factors (successful hunting or, for example, the quality of the berry harvest in the vicinity).

A modern person gets calories in much larger quantities and without much energy expenditure. And all the nutritional problems that remain with Homo Sapiens are the right combination of macronutrients important for life, ensuring a balance in the intake of proteins, fats and carbohydrates. But even this, alas, fails for many.

The moment a person bites into a slice of meat, a pie, or a vegetable, a complex process of digestion begins. The body processes each ingested piece of food, breaking it down into the smallest organic substances. A complex of chemical reactions transforms food from its usual form into individual chemical components that serve as fuel for many processes. Proteins, carbohydrates and fats go through a long metabolic process. And each macronutrient has its own, unique.

When these three substances are present in the required amount, first of all, sugars and fats are used as an energy source, because there is a relationship between the metabolism of carbohydrates and lipids. Proteins at this time serve as a building basis for muscles, hormones.

Protein derived from food, the body breaks into pieces (amino acids), which are then used to create new proteins with specific functions. They accelerate some chemical reactions in the body, contribute to the relationship between cells. With a deficiency of carbohydrates and fats are a source of energy.

Lipids typically provide the body with almost half of the energy it needs. Fat obtained from food is broken down into fatty acids, which are sent in the blood. Triglycerides are stored in fat cells.

However, carbohydrates can only be stored in the body in small amounts. Obtained from food, they are also broken down into small pieces and already in the form of glucose enter the circulatory system and liver, affecting blood sugar levels. The body will more easily accept and process a larger portion of sugars than fat. The remaining carbohydrates (those that the liver is unable to store in itself for the manufacture of glucose) are converted into long-term fat. When the body feels a shortage of carbohydrates, it uses such fats from reserves for energy.

And although lipids are a good source of energy for almost the entire body, there are several types of cells that have special needs. The main ones on this list are neurons (brain cells). They work well if the diet includes carbohydrates, but almost cannot function on fat alone. A low-carb diet is dangerous for brain function.

Protein deficiency is no less dangerous: with a lack of proteins, the body begins to destroy its own muscle cells.

instead of an epilogue

Macronutrients are used as building blocks. Healthy fats take care of the preservation of cell membranes and prevent inflammatory processes. A menu made up of the right products is a guarantee that the body will receive complex carbohydrates, “good” fats and proteins in the required amount.

In addition, a balanced diet is a full range of nutrients, minerals, vitamins and trace elements important for health. It is the interconnection of the elements of the full spectrum of nutrients that will protect against diseases and early aging, provide the necessary energy and strength. Well, of course, do not forget about the 6-8 glasses of water recommended by nutritionists, which are necessary for the implementation of chemical processes.

Table of proteins, lipids and carbohydrates in some products
Product (100 g)ProteinsFatsCarbohydrates
Sweet pepper1,24,6
Fruits and berries
Pearl barley3,41,273,6
Dairy produce
Cottage cheese p / w16,89,11,4
Yogurt 1,5%51,43,6
Products of animal origin
Chicken breast20,78,60,5
Pork n / w16,327,9
Red caviar (sturgeon)28,89,8
River perch18,60,9
White mushrooms (fresh)3,20,51,7
Nuts and Seeds
Sunflower seeds20,652,85,1
Bakery products
Rye bread4,60,649,7
Bread, wheat7,82,353,3
Black chocolate5,335,252,5
milk chocolate6,835,652,3
Vanilla ice cream3,51123,6
Fiber Content Rating
Product (100 g)Fibre
Bran40 g
Flax-seed25-30 g
dried mushrooms20-25 g
Dried fruits15 g
pulse10-13 g
Whole wheat bread7-9 g
Berries5-8 g
Fruit (sweet)2-5 g
Avocado6-7 g

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