In a healthy diet, nutritionists consider the energy value of products to be one of the main criteria, which reflects the level of usefulness of each type. Measure it in calories. These units are the amount of energy that a person receives from food. A sufficient amount of calories helps to restore good spirits and maintain peace of mind during the working day.
The different degree of usefulness of certain dishes allows you to create a daily diet so that the body not only collects a sufficient amount of necessary calories, but also receives a full volume of vitamins and minerals. Nutrition experts advise when choosing products in the store at the same time pay attention to their energy value and chemical composition.
For what purposes does the body spend energy
Most people tend to think that we need calories exclusively for exercise. However, scientists found that approximately 65-70% of the total energy received from food helps the body maintain the normal course of physiological processes: thermoregulation, sleep, digestion, heart and blood vessels, skin regeneration, the formation of new cells, nail and hair growth, and also many others. In addition to providing the basic energy needs necessary for the full work of organs, we need calories for:
- Maintaining habitual body movements during daily activities.
- Intensive workload - for physical labor or strength training.
Knowing the total energy value of foods eaten per day, you can calculate how much the body spends on natural needs, and how many calories it will need to burn for weight loss, in order to ultimately get a negative balance.
Specialists in sports nutrition have found that our contemporary consumes about 25-30% of the energy consumed from food for physical activity. To maintain health and an ideal figure, nutritionists recommend increasing this parameter to 40%. Kilocalories that a person did not spend during the day are deposited in a fat depot at the waist, on the sides and other problem areas.
What are calories and kilocalories ?
Food calories are a certain amount of energy released by the body from foods during digestion and assimilation. The calorie content of dishes or individual products is a potential energy charge that a person receives if the food is absorbed completely.
Calories are units used to measure the energy value of food. It is known that food calories, in contrast to the unit of the same name used in a scientific context, contain 1000 times more energy. That is why nutritionists and adherents of healthy lifestyles, when mentioning kilocalories, often omit the prefix “kilo”, talking about the effectiveness of a particular food product. In Europe, kilocalorie is designated as Kcal, in the USA it is customary to reflect the unit of food value of food by the term calories, or abbreviated cal.
How to determine the energy potential of food and calorie consumption in humans
Scientists, examining the caloric value of food, burn products in the calorimeter and calculate the amount of heat released into the water bath surrounding the device. They found out: one calorie is enough to heat 1 liter of liquid at 1 ° C. For example, the equivalent of the pie’s energy value (150 cal) allows you to heat 150 liters of water by 1 degree or bring 1.5 liters of liquid to a boil. In another measuring system, the energy value of food is calculated in kilojoules. It is believed that 1 kilocalorie and 4.184 kJ are identical values, as well as 1 kilojoule (1kJ) and 0.238846 cal:
Food components | Per 1 g of product |
| Kcal | Kj |
| Proteins (proteins) | 4.10 | 17.1 |
| Fats | 9.30 | 39 |
| Carbohydrates | 4.10 | 20.1 |
| Cellulose | 1.9-2.0 | 8.10 |
| Alcohol | 7.2 | 26.1 |
| Sweeteners | 2,5 | 10.2 |
| Citric Acid | 2.25 | 9.1 |
To determine the metabolic rate in humans, they place them in a ventilated chamber with reliable thermal insulation. A constant temperature is maintained inside the room, and heated air due to the heat released by the body of the test person is pumped through pipes to a reservoir of cold water. So it was found that the daily energy requirement of a person whose work is associated with a sedentary lifestyle is approximately 2000 kcal.
Daily calorie intake
The daily human need for calories, according to the standards adopted in European countries, for a man of average build varies between 2500 units, for a woman - 2000 units. In addition to gender differences, it depends on weight, age, height, metabolic rate and lifestyle. In 1919, scientists at the Carnegie Institution in Washington deduced the optimal formula, named after the authors - Harris and Benedict. With its help, the calculation of the level of basic metabolism for men and women was performed on the basis of biometric data:
The results of this calculation show how many calories per day a person needs to get from food or what the total energy value of the products should be in order to meet their basic needs.
Correction of human daily energy requirements
Depending on the type of work performed, the amount of required calories for a person varies (based on 1 kg of body weight):
- Mental work: 30-50 kcal.
- Light labor: 30-40 kcal.
- Heavy physical labor or strength training: 40-50 kcal.
Using the coefficients of physical activity, you can most accurately determine the individual daily energy requirement:
Physical activity (per week)Coefficient | Volume |
1,2 | Minimal or total lack of load |
1.38 | 3 training with medium load |
1.46 | 5 trainings with medium load |
1.55 | 5 intensive trainings |
1,64 | Daily workload |
1.73 | Intensive training seven days a week or twice a day |
1.9 | Professional sports or hard physical work |
For those who wish to reduce body weight
Nutritionists warn that the ratio of calories received daily from food and spent in the process of life should be zero or negative. Otherwise, when the first prevails over the second, metabolic disturbances occur in the body and a person gains weight. Those who want to lose weight need to reduce the calorie intake of the daily diet by 300-500 kcal. In order to burn 1000 g of fat, you need to spend at least 7700 cal. Nutritionists consider getting rid of 2-4 kilograms within a month to be optimal weight loss (this amount does not include the amount of water excreted from the body during training). To speed up the process of thermolipolysis and spend calories due to fat reserves, it is necessary to reduce the calorie content of the daily diet.
To do this, when visiting supermarkets should pay attention to the energy value of products and composition. It must be taken into account that fats are able to cover only 30% of a person’s energy needs, while carbohydrates provide 58% of the life force. Foods rich in these organic substances are very high in calories: dried fruits compete in energy value with fatty meats. It should be remembered that the diet of modern man is usually oversaturated with fats and hidden sugar, so the proportion of foods rich in fats should be reduced by redistributing it in favor of fresh vegetables and fruits, mushrooms, legumes, as well as other plant foods containing complex carbohydrates .
Energy and nutritional value of products
The nutritional value of each product includes the whole range of its beneficial properties: energy, biological, organoleptic, physiological, as well as high quality and digestibility. Calorie content is directly related to the amount of certain nutrients contained in food: fats, proteins, carbohydrates and organic acids.
Nutritionists have calculated that when thermolipolysis, or the breakdown of fats (1 g), the body receives 9.3 cal, with the catabolism of carbohydrates and proteins - 4.1 cal. When calculating the energy value of food products, integers are usually used, rounding them:
| Squirrels | 17 kJ | 4 cal |
| Fats | 37 kJ | 9 cal |
| Carbohydrates | 17 kJ | 4 cal |
| Fiber (plant fiber) | 8 kJ | 2 cal |
| Organic acids | 13 kJ | 3 cal |
| Ethanol | 29 kJ | 7 cal |
| Polyols (polyols) | 10 kJ | 2,5 cal |
The amount of BZHU, as well as other ingredients contained in 100 g of the product, can be found on the store label or taken from a table indicating its composition and calorie content. Multiplying these figures by the amount of energy obtained from 1 g of the food component, we find the energy value of each nutrient in 100 g of the product. But at the same time, it should be borne in mind that the human body is not able to absorb food by 100%. He digests:
- 84.5% protein;
- 94% fat
- 95.6% carbohydrates.
Therefore, to find out the exact data of the amount of energy that can be extracted from a particular product, you need to use the amount of nutrients absorbed by the body.
Calorie tables and chemical composition of products - one of the main helpers in losing weight
In order to keep yourself in great shape, it is very important to calculate the energy value of the products consumed every day, as well as to control the amount of calories received and consumed. In the future, it will be difficult to force the body to spend an excess supply of energy. Having not received a boost of vigor from food, the human body begins to slow down the metabolism in a panic. This allows you to save body fat as a saving reserve from possible starvation in the future, but thereby prevents weight loss. Using the prepared data on BZHU (proteins, fats and carbohydrates) from the tables, by multiplying them by the energy value of 1 g of nutrient, we obtain the calorie content of each of them in 100 grams of the product. For example, kefir with a fat content of 2.5% contains per 100 ml of product, respectively:
- 2.5 g of fat (2.5 g x 9 units) = 22.5 cal;
- 3 g of protein (3 g x 4 units) = 12 cal;
- 4 g of carbohydrates (4 g x 4 units) = 16 cal.
Summarizing the results, we obtain an energy value of 100 g of kefir, which is 50.5 units or about 51 kcal, as indicated on the label.
Calorie content of the finished dish
If the calculation of the energy value of products is a fairly simple process, then identifying the calorie content of cooked dishes is painstaking work.
It is necessary to weigh all the ingredients of a particular dish on a kitchen scale, taking into account not only the main components, but also the additional ones. Especially increase the energy value of food products such as butter (butter or vegetable), sour cream, mayonnaise.
Substitution of sour cream, ketchup or the same mayonnaise (including its “lean” or “light” types) with natural yogurt or kefir with a fat content of 1-2.5% in a salad significantly reduces the number of calories consumed. Knowing the weight, chemical composition and energy value of products intended for breakfast, you can calculate its total calorie content:
- Toast from a bun (50 g) = 149 kcal.
- Turkey 20 g = 19 kcal.
- Cheese 20 g = 80 kcal.
- Tomato (medium size) = 25 kcal.
- A cup of coffee (130 ml) = 0 kcal, adding milk 2.5% (10 ml), add 5 kcal, and pouring sugar 5 g (1 tsp), increase the calorie content of food by another 20 kcal.
We add up the calculated values of the energy value of individual food components and obtain the total number of calories consumed in the morning: 149 units + 19 units + 80 units + 25 units + 25 units = 298 kcal. If you want to spread toast with butter (5 g), you will have to increase the result by 75 cal. In this case, breakfast can give the body 373 cal.
To determine the energy value of the finished dish, taking into account additional ingredients and losses during heat treatment, you will need: a list of products according to the recipe and the weight of all ingredients in grams. For example, 100 g of raw chicken contains protein - 18 g, fat - 18.5 g, carbohydrates - 0.8 g. 150 grams of chicken contain: 27 g of protein, 28 g of fat and 1 g of carbohydrates. Theoretically, the energy value of 150 g of chicken is 364 kcal, of which:
- Proteins 27 g x 4 kcal = 108 kcal.
- Fats 28 g x 9 kcal = 252 kcal.
- Carbohydrates 1 g x 4 kcal = 4 kcal.
When boiling in water, the calorific value of which is 0 kcal, the energy value of this product will not change. After a dietary piece of boiled chicken is eaten and digested, taking into account the digestibility of various nutrients, its calorie content will be 329 kcal:
- Proteins 108 cal x 84.5% = 91 cal.
- Fats 252 cal x 94% = 237 cal.
- Carbohydrate 1 cal x 95.6% = 0.96 cal.
Why are mono-diets harmful?
When choosing a diet, it is necessary to monitor not only its calorie content, but also to ensure that all categories of substances necessary for life support are presented in it: BJU, vitamins, minerals.
The chemical composition and energy value of food are important factors that have a significant impact on the quality of human life. Eating a depleted diet, the basis of which is a single product, you can get a short-term stunning result of losing weight, but at the same time significantly undermine your health.
The body under this diet works for wear. According to healthy lifestyle adherents, counting calories is easy. Beginners in two weeks by eye will determine the calorie content of familiar dishes, paying attention only to products that are consumed for the first time. At the same time, this method helps well, without harm to health, lose weight and permanently consolidate the result.