Carbohydrates (good, bad): fattening? Foods, types and more

Carbohydrate is a very common term in matters of health and fitness.

Those who go to the gym or practice aerobic activities, such as running or cycling, generally know that it is necessary to consume good sources of the nutrient to maintain physical performance.

And to reduce some measures? You can start a nutritional monitoring by reducing it with each meal.

But do you know all about the most abundant organic molecule on the planet?


What is carbohydrate?

In chemistry, carbohydrates are defined as organic molecules that have a structure of carbon, hydrogen and oxygen. In addition, they can be termed as carbohydrates, carbohydrates or sugars.

The chemical formula of the substance is (CH2O) n, which refers to the substances Carbon, Hydrogen and Oxygen, also referring to carbohydrates as carbohydrates.

The nutrient is used as an energy source by living systems and helps in the formation of cell structures and nucleic acids. Animals ingest carbohydrates through food, and it is one of the most common substances in food.

The main functions of the nutrient in the body are related to energy storage, energy production and cell structure.


There are 3 types of carbohydrates, which are called mono, di and polysaccharides. Although the names are not so popular, the substances that make up each group are part of the diet of most people.

Monosaccharides present glycoses, found in honey, potatoes and flours, for example; fructose, which is the sugar in fruits; and galactose, which is present in milk and its derivatives.

In disaccharides, also known as oligosaccharides, there is sucrose, composed of white sugar, for example; maltose, obtained through some cereals such as barley; and lactose, which is milk sugar – the one that many people have allergies or intolerance to.

Polysaccharides are composed of starch, which is present in grains and cereals, such as wheat, rice and potatoes, and cellulose, which is present in fruits, vegetables, vegetables, nuts and seed husks.

These groups – mono, di and polysaccharides – are divided into simple and complex carbohydrates. While the simple ones are formed by 1 or 2 sugar molecules, the complexes have larger structures.

The differentiation between these two groups occurs, above all, in digestion.

Simple and complex carbohydrates

Mono and disaccharides are called simple carbohydrates. This is due to their reduced chemical structure. Polysaccharides are classified as complex because they have a larger chemical chain.


As they have a simpler chain (structure), they are quickly digested.

Generally, foods that have higher levels of simple carbohydrate are those that are most desired and generally least recommended in daily food, such as candies, chocolates and white pasta.

But this group also includes fructose and lactose, which are found in fruits and dairy products. These foods, despite having simple carbohydrates, are rich sources of vitamins and nutrients.

When ingested, carbohydrate molecules cause a very rapid rise in glucose (or sugar) in the blood and cause spikes in insulin, which is a blood sugar regulating hormone.

After the action of insulin, the tendency is for the body to feel hungry quickly, because the level of glucose continues to fall.

Therefore, when someone wants to lose weight, it is recommended that the simple type of carbohydrate be reduced, also to avoid the induction of hunger by glucose changes.

These carbohydrates are found in some foods, such as:

  • White rice;
  • Noodle;
  • White bread;
  • Soda;
  • Candy;
  • Cookies;
  • Ice cream;
  • Isotonic drinks;
  • Chocolates;
  • Milks and derivatives.


When several carbohydrate molecules come together, they are called complex structures.

In foods, the structures are usually associated with fibers, causing the digestion and arrival of glucose in the blood to be gradual and slower, preventing blood sugar from rising quickly and insulin spikes.

Due to the moderate release of the nutrient, complex carbohydrates give the body energy for longer.

This type of carbohydrate is found mainly in:

  • Whole grains (rice, bread and pasta);
  • Cassava;
  • Sweet potato;
  • Vegetable;
  • Chickpea;
  • Pumpkin;
  • Oat;
  • Broccoli;
  • Corn and pea;
  • Linseed.

As they are slow-release nutrients, they tend to give you more satiety. That is, it is these foods that are generally indicated to lose weight and gain more energy in physical activities.

Function in the organism

The nutrient is essential for the functioning of the body, being used in basic functions of the organism, such as providing energy for cellular activities. In addition, carbohydrate is necessary for metabolic functions and cell composition.

There is not an ideal fixed number of carbohydrates to be consumed daily. The amount may vary according to the conditions and characteristics of each person.

As the substance is used to obtain muscle energy, the more physical activities a person does, the more carbohydrate is needed for the body to obtain energy and maintain the rhythm of exercise and other organic functions.

It is important to remember that it is not just physical exercise and sports that use energy, but all activities, such as walking, sweeping the house, reading and even standing still.

This is because the body spends energy to perform even its most basic functions, such as beating the heart, breathing and digesting food,.

In general, carbohydrate consumption should be between 45% and 65% of the total calories ingested. To find out how much this represents in your daily diet, the count is simple: each 1 gram of carbohydrate corresponds to 4 calories.

So, imagine that your nutritional need is around 1800 calories per day. Doing a percentage calculation, we have:

45% of 1800 (45 * 1800/100) = 810

65% of 1800 (65 * 1800/100) = 1170

That is, the ideal is that between 810 and 1170 calories that you eat, come from carbohydrates. To find out how many grams of CHO this represents, just divide the value by 4, as soon as each 1 carbohydrate equals 4 calories:

810/4 = 202,5

1170/4 = 292,5

So, the average consumption of the nutrient should be between 202g and 292g of CHO per day.

Carbohydrate digestion process

Initially, carbohydrates are broken down into smaller structures.

Digestion is carried out by enzymes from the gastrointestinal system (SGI), also called the digestive system.

The process, which begins in the mouth, acts by breaking or fragmenting the molecules. This degradation is called hydrolysis.

Also in the mouth, an enzyme called ptialin or salivary amylase is secreted. The enzymatic action breaks some bonds between the carbohydrate molecules, but not all.

Thus, they make up an initial or incomplete digestion process. As the food travels to the stomach, the salivary enzyme continues to work. Only when it reaches the gastric space that its action is terminated by the acidic pH, present in the stomach.

The pancreas participates in digestion by releasing an enzyme called pancreatic amylase, responsible for breaking down starch into maltose.

But it is mainly in the small intestine that most carbohydrate digestion occurs. At that point, an enzyme called maltase acts by breaking down maltose into two glycoses.

The molecular chains are broken in succession, until they result in glucose, fructose and galactose monosaccharides. These substances can finally be absorbed by the enterocyte (which are cells on the surface of the intestine).

Absorption occurs through the transport of these molecules into the bloodstream. The degraded and digested carbohydrate is used as cellular energy, being distributed to cells and tissues so that they can perform different functions.

Therefore, this energy is quickly used. When there is a greater supply and absorption of carbohydrates than the body currently needs, the rest is stored in the form of glycogen.

There are some fundamental enzymes in the carbohydrate digestion process, which are:

  • Salivary amylase : released in the mouth;
  • Pancreatic amylase : released in the small intestine;
  • Sucrase : released by the cells of the small intestine;
  • Maltase: released non-small intestine;
  • Lactase : released in the small intestine.

Carbohydrate in the bloodstream

The simpler the carbohydrate, the faster it will reach the bloodstream.

It can be said that the slower the process of getting to the blood, the lower the glycemic index of the food. That is, simple carbohydrates have a high glycemic index, while complex carbohydrates have lower rates.

Regardless of the type or classification of carbohydrate, when it reaches the bloodstream, the body releases hormones that regulate glucose rates and prevent decompensations in the body.

The main hormones that act in the regulation of blood glucose are:

  • Insulin : it transports glucose into cells, helping to control blood glucose levels;
  • Glucagon : stimulates the processes of converting glucose into glycogen and from glycogen to glucose in the liver;
  • Adrenaline : acts on the breakdown of glycogen and helps the release of glucose by the liver;
  • Cortisol : acts as a stimulant for the body to obtain energy through other unusual substances, such as carbohydrates and proteins.

In summary, we have: ingestion, digestion, absorption into the bloodstream, transport into cells and, finally, the energetic cellular use, which results in energy for the organism to continue its functions.

After the carbohydrate is absorbed

Glycogen can be accumulated in the liver and muscles. While hepatic glycogen (from the liver) constitutes a more accessible reserve of energy and comprises about 100g to 120g of glycogen, in the muscles, the substance can comprise about 350g.

After being stored as glycogen, carbohydrates are stored for later use as an energy source, which is called the glycogenesis process . That is, the synthesis of glucose into glycogen.

While hepatic glycogen acts to maintain glycemia between each food, avoiding harmful variations to the body, muscle glycogen acts as an energy source for the muscle itself, for example, in muscle contractions during physical activities.

Later, when the body converts glycogen into glucose (or energy), the process is called glycogenolysis .

Where does the energy go?

Several organs, tissues and cells are fed with energy from carbohydrates.


According to the University of Notre Dame, in the USA, about 19% of the energy produced by the body goes to the use of the brain.

Synapses, which are the communication between neurons, use a good amount of energy. In general, the neuronal region is most severely affected when glucose is lacking in the body.

That is, if the body cannot convert nutrients into energy and perform its functions correctly, severe and permanent damage to brain functions can occur.

Skeletal muscles

Walking, running, cycling, moving your arms, raising a glass or just waving to someone you know are activities that require a lot of energy, due to muscle contraction processes.

To perform these functions, cells convert muscle glycogen stores into energy. This is the most easily accessible energy store, as it is produced to be used quickly.


The heart, in healthy conditions, keeps its frequency constant, but that can be altered according to external or internal factors.

These heart rate changes are not necessarily risky conditions, for example, performing physical activities or changing the temperature of the environment tend to change the heart rate.

To maintain the proper functioning of the heart, pumping blood to the body, energy consumption is necessary. That is, even in absolute rest, the heart uses glucose to function.

Spleen and liver

While the spleen has immunological and hematological functions, acting to protect the body and filter the blood, the liver performs several regulatory and digestive functions.

Among the liver functions (of the liver) are:

  • Participation in digestion through the secretion of bile;
  • Extracting glucose from food and transforming it into glycogen to be used or stored in the muscles;
  • Production of some specific proteins, such as albumin;
  • Aid in the defense of the organism through the filtering of microorganisms;
  • Cholesterol synthesis to be excreted by bile.

Together, the organs demand about 27% of the body’s energy. In addition, the liver is responsible for storing hepatic glycogen, the one that was produced and was not used immediately.

Thus, the liver is essential for the body to endure long periods without eating, including at night, without letting blood glucose levels be severely reduced and affecting the body’s functions.


The kidneys receive about 10% of the body’s energy. Most of the energy demand is for the production of urine, while the rest is used in the production of hormones or, still, in the elimination of toxins.

Good and bad carbohydrates: what’s the difference?

Many diets highlight the importance of consuming good carbohydrates and avoiding bad ones, as they are the most favorable to weight gain.

In general, what is meant is that foods high in sugar, with a simpler chain of carbohydrates, are processed quickly and, therefore, are considered bad.

When eating a bad carbohydrate, the tendency is for it to be degraded and reach the bloodstream quickly, raising the blood glucose level. At that time, the body releases higher insulin rates to control peak blood glucose.

The tendency is for blood glucose to continue to fall and the body to feel hungry more briefly as a warning sign.

Therefore, for those who want to lose weight or decrease their appetite, the ideal is to prefer foods with complex carbohydrate chains. That is, the good ones.

In addition to having a low glycemic index, they usually have higher amounts of fiber, which make digestion slower and also contribute to the improvement of intestinal transit.

Not all simple carbohydrates are bad. For example, fruits have fructose, which is a simple carbohydrate. However, they are natural foods, rich in vitamins and containing high amounts of fibers present in the skin or bagasse, generally.

Therefore, they are indicated as beneficial to the body.

Types and examples of carbohydrates

Below you will find a list of foods that are generally part of the consumption habits of Brazilians and their respective amounts of carbohydrates.

15 good carbohydrate foods

  1. Black beans : 63g of CHO (every 100g);
  2. Oats : 56.5g of CHO (every 100g);
  3. Chickpeas : 30g of CHO (every 100g);
  4. Sweet potatoes : 20g of CHO (every 100g);
  5. Lentils : 20g of CHO (every 100g);
  6. Apple : 19g of CHO (every 100g);
  7. Peanuts : 16g of CHO (every 100g);
  8. Wholemeal bread : 12.3g of CHO (per slice);
  9. Skimmed natural yogurt : 8g of CHO (every 100g);
  10. Broccoli : 7g of CHO (every 100g);
  11. Cabbage : 6g of CHO (every 100g);
  12. Eggplant : 6g of CHO (every 100g);
  13. Raw carrot : 5.84g of CHO (every 100g);
  14. Tomato : 4g of CHO (every 100g);
  15. Asparagus : 3.9g of CHO (every 100g).

It is important to remember that the processing of carbohydrates depends not only on the amount of carbohydrates, but also on the glycemic index, that is, how fast this sugar will reach the bloodstream.

Some foods have small levels of the nutrient, but are quickly synthesized because they are a source of simple carbohydrates, along with low amounts of fiber or protein .

Others, even if they have higher rates, such as whole grains, gradually provide energy to the organism, and must be inserted in the diet, such as sweet potatoes.

8 bad carbohydrate foods

  1. Industrialized soft drinks and juices : approximately 50g for each 350ml;
  2. White rice : 28g of CHO per 100g;
  3. French fries : 41g of CHO every 100g;
  4. Biscuit water and salt : 5g per unit;
  5. Stuffed cookie: 12g per unit;
  6. Industrialized cakes (Ana Maria type) : 27g per unit (50g).
  7. French bread : 28g per unit;
  8. Loaf of bread : 14g per slice;

Read more: Natural and processed foods: understand the difference

6 foods that don’t look but have a lot of carbohydrates

Some foods may have high carbohydrate levels and are often unknown to consumers.

Misinformation occurs because, in general, it is known that carbohydrate is found in flours and sweet foods.

But several products, especially industrialized ones, can have very high values ​​of the nutrient. For example:

  1. Salad dressings : in addition, the product is rich in sodium and preservatives, which can be harmful to health;
  2. Special coffees: pure coffee is a low carbohydrate food, but the special versions (with chocolates and whipped cream) or ready-to-prepare powders generally have high levels of carbohydrates and calories;
  3. Yogurts : although the natural versions are quite healthy, if the yogurt has syrups or toppings, the amount of carbohydrates tends to be very high;
  4. Prepared meats : the meat itself is low in carbohydrates, but the way of preparing it can give a high rise in that rate. Spices, sauces and breaded versions may be responsible for increasing CHO rates;
  5. Soy meat : although soy is a grain rich in vitamins, unlike animal meat, it has high levels of carbohydrates;
  6. Seeds and nuts : even though they are rich in fiber and quite common in diets, the seeds have high levels of carbohydrates. Despite this, they are still beneficial foods to the diet, if consumed moderately.

It is necessary to remember that carbohydrates are necessary for the organism and that their adequate consumption is indispensable for the proper functioning of organic functions.

Not all foods with high levels of the nutrient should be avoided, as is the case with seeds and nuts, which can provide good sources of vitamins and nutrients.

These foods have low glycemic indexes and high amounts of fiber, causing carbohydrates to be released gradually into the blood and making excellent nutritional sources.

What is glycemic index (GI)?

The glycemic index is a food scale that defines how fast the absorption of carbohydrates in food will be.

Therefore, even if a product contains a large amount of CHO, it does not necessarily mean that it should be removed from the diet.

For example, grains, seeds and whole grains are a source of carbohydrates, reaching up to 47g per 100g portion.

However, this sugar contained in the product is ingested along with a large amount of fiber, vitamins and good fats. In addition to properly nourishing the body, seeds and whole grains need to be further degraded due to the complexity of the structure.

With the gradual release of glucose into the blood, insulin spikes (which can lead to hunger more quickly) are avoided and the excess glycogen stock is reduced (one that was not used immediately by the body).

Foods can be classified with glycemic index (GI):

  • Low GI : less than 50;
  • Average GA : between 50 and 70;
  • High GI : above 70.

Low glycemic index foods

There are several foods with significant amounts of carbohydrate, but which are processed slowly by the body, avoiding insulin spikes. These are called good carbohydrates.

In addition to products with a complex CHO chain, other factors imply a suitable food for frequent consumption. Are they:

High amount of protein and good fats : both proteins and fats cause absorption through the intestine to be slower.

In addition, proteins assist in muscle structuring, being ideal for preserving muscles, especially when the person is on diets or in the process of losing weight.

Good fats are essential for the functioning of the body and must compose meals in a balanced way.

Fibers : Soluble fibers act as a barrier between the food ingested and the intestinal walls. This makes glucose more difficult to get into the bloodstream and therefore is slowly released.

In addition, insoluble fibers assist in the correct functioning of the intestine, composing the fecal bolus and, consequently, improving the frequency of evacuation.

Of course, foods do not always have low glycemic indexes. However, they do not need to be eliminated from the diet. A good alternative is to prepare meals combining nutrients.

For example, traditional French bread is made with white wheat flour, which is quickly processed by the body. However, by adding lettuce leaves and white cheese, the snack raises its protein and fibrous amounts, becoming more balanced.

Foods with a high glycemic index

Unlike low GI, foods with a high glycemic value generally have little fiber and protein.

The best known are white rice, white flours and refined sugar. But there are also tapioca and natural juices that quickly raise blood glucose.

Although nutritionists indicate that it is generally better to consume a natural juice than a soft drink or industrialized juice, they still point out that the juice has disadvantages in relation to the consumption of the whole fruit.

This is because, in general, it is necessary to use more fruit to obtain a glass of juice (for 250 ml of orange juice, it may be necessary to use 3 or 4 units).

In addition, the bagasse, the peel and the semenesthes are strained or discarded from the juice extraction, drastically reducing the amount of fiber and even vitamins in the food.

Therefore, the ideal is to prefer the consumption of the whole fruit. But, compared to other industrialized liquids, natural juice still offers a high amount of nutrients and vitamins, in addition to having no preservatives.

What is the glycemic index of foods?

The University of Sydney portal links studies and reviews on the glycemic index of foods and food groups, as well as their classification as to food quality (high or low GI).

The carbohydrate molecules or chains have the following classification regarding the glycemic index:

  • Glucose : GI of 100 – High GI;
  • Sucrose : 60 GI – Medium GI;
  • Fructose : GI of 23 – Low GI;
  • Lactose : GI of 46 – Low GI.

Below you will find a summary table from Harvard University, which lists some foods, the glycemic index and the amount of carbohydrates present in each serving.

Cereals and processed products :

  • 30g of white bread: IG of 71 and 10g of carbohydrate;
  • 30g of wholemeal bread: IG of 71 and 9g of carbohydrate;
  • 180 g of cooked spaghetti: IG of 46 and 22g of carbohydrate;
  • 180 g of cooked whole spaghetti: IG of 42 and 17 g of carbohydrate;
  • 50g of corn chips: IG of 42 and 11g of carbohydrate;
  • 20g of microwave popcorn: IG of 55 and 6g of carbohydrate;
  • 50g of potato chips: GI of 51 and 12g of carbohydrate;
  • 250g of oats: IG of 55 and 13g of carbohydrate;
  • 150g quinoa: GI of 53 and 13g of carbohydrate;
  • 150g of white rice: IG of 89 and 43g of carbohydrate;
  • 150g of brown rice: IG of 50 and 16g of carbohydrate;
  • 50g of ice cream: IG of 57 and 6g of carbohydrate;
  • 250 mL of whole milk: IG of 41 and 5g of carbohydrate;
  • 250 mL of skimmed milk: GI of 32 and 4g of carbohydrate.

Fruits and vegetables and seeds:

  • 120g of Apple: IG of 39 and 6g of carbohydrate;
  • 120g of banana: GI of 62 and 16g of carbohydrate;
  • 120g of grape: IG of 59 and 11g of carbohydrate;
  • 120g orange: IG of 40 and 4g of carbohydrate;
  • 120g peach: GI of 42 and 5g of carbohydrate;
  • 120g pear: IG of 38 and 4g of carbohydrate;
  • 60g prunes: GI of 29 and 10g of carbohydrate;
  • 60g raisin: IG of 64 and 28g of carbohydrate;
  • 120g watermelon: IG of 72 and 4g of carbohydrate;
  • 150g black beans: GI of 30 and 7g of carbohydrate;
  • 150g chickpeas: 10 and 3g carbohydrate GI;
  • 80g carrots: 35 g and 2 g carbohydrate;
  • 150g cooked potato: IG of 82 and 2g of carbohydrate;
  • 150g sweet potatoes: GI of 70 and 22g of carbohydrate;
  • 50g cashew nuts: GI of 27 and 3g of carbohydrate;
  • 50g peanuts: GI of 7 and 0g of carbohydrate;

Carbohydrates and diabetes

People with diabetes need to control their carbohydrate intake. This does not necessarily mean to avoid or drastically reduce it, but it is necessary to measure intake to regulate medications, when necessary to use them.

The carbohydrate intake ratio is more delicate for people who already have a diagnosis of diabetes or pre-diabetes. In such cases, the diet must be accompanied and suggested by a nutritionist or nutrologist.

But there is a myth about the relationship between excess carbohydrate and sugar consumption and the development of diabetes.

The truth is that there is an indirect relationship between food and type 2 diabetes. This is because excessive consumption tends to lead to weight gain.

With the accumulation of fats and other associated factors (genetic conditions, for example), a person can develop type 2 diabetes, which is basically insulin resistance.

Type 1 diabetes, on the other hand, is an autoimmune condition, in which the body attacks its own cells, causing little or no insulin to be released to the body. That is, there is no direct or indirect relationship between the disease and the consumption of carbohydrates.

Carbohydrate is fattening?

Carbohydrates are a necessary source of energy for the body to properly perform its functions.

If consumption is balanced, that is, according to the body’s energy expenditure, carbohydrates do not accumulate. That is, do not put on weight.

But if the balance is uneven (when the person consumes more than is necessary and usually through foods rich in bad carbohydrates) there is a tendency for the body to increase the fat index.

After the meal, there is an increase in blood glucose supplying glucose to all tissues. At that time, the liver and muscles store glucose in the form of glycogen.

However, there is a limit capacity for this glycogen to be stored. So, in general, this surplus favors the accumulation and accentuation of lipids, that is, fat cells.

Therefore, carbohydrate intake, in itself, is not fattening. But it is the surplus that provides the weight gain.

Read more: Foods that put on weight fast and healthy

Does cutting carbs lose weight?

Many diets suggest that a diet low in carbohydrates or sometimes with almost zero amounts of the nutrient be followed.

The so-called low carb diets became popular and are indicated for several goals besides weight loss.

Among the suggested benefits, the improvement in the quality of food, the maintenance of muscle mass, the promotion of well-being and the greater hormonal balance are the most cited.

The food plans that have gained fame and visibility are mainly:

  • Lowcarb diet : low carbohydrate intake, with varied menus;
  • Paleolithic diet : food based on natural foods, consumed by human ancestors (based on vegetables, meat and fruits);
  • Protein diet: the consumption of lean proteins (lean meat, eggs and skimmed milk) increases, reducing the consumption of carbohydrates;
  • Egg diet : insert eggs into 1 or more meals daily, usually reconciled with the reduction of carbohydrate consumption;
  • Sweet potato diet : in general, the diet plan is indicated for athletes or practitioners of intense physical activities, as it offers the body a complex source of carbohydrates. Thus, the organism has energy for longer periods;
  • Complex carbohydrate diet : the practice consists of choosing only foods with complex carbohydrates, that is, the good ones. Among them, whole grains and with a high fiber index.

Why reduce carbs lose weight?

When the body no longer has immediate sources of glycogen to convert to energy, processes are initiated that burn or expend fat cells to obtain the necessary energy.

This process is called ketogenesis. In general, the condition is a natural process of the body, which acts in order to maintain energy sources if there is a very long time without receiving food, for example, during sleep.

The body then uses fat cells to prevent blood glucose from falling (which can cause severe damage to the body) and maintain cell function properly.

So, the weight loss process through the reduction of carbohydrates causes the body to be induced to resort to adipose tissue and, consequently, results in the loss or reduction of measures.

The adoption of these so-called ketogenic practices and diets (which induce weight loss by restricting carbohydrates) still generates debates and different positions from doctors and nutritionists.

While some point out that keeping carbohydrate intake levels low would be beneficial to the body, others point out that it can cause muscle mass loss.

In addition, reports of malaise, dizziness, weakness and difficulty in adapting to the diet are frequent.

In some cases, symptoms subside and disappear over the first few weeks of the diet, but some people may experience persistent malaise and an inability to adapt.

Carbohydrates are essential to maintain the proper functioning of the body. Its consumption must be balanced and associated with other healthy habits and adequate choices that meet the nutritional needs of each person.

All food and menu planning must be indicated and monitored by nutrition professionals, so that health risks are avoided.

Read more about other substances and their actions in the body here on our blog!