To provide a person with food that corresponds to his energy expenditure and plastic processes, it is necessary to determine the daily energy expenditure. The unit of measurement of human energy expenditure is taken to be a non-systemic unit of heat quantity - calorie (1 cal = 4.1868 J).

During the day, a person spends energy on the work of internal organs (heart, digestive system, lungs, liver, kidneys, etc.), heat exchange and performing activities such as work, study, housework, walking, rest, etc. The energy spent on the work of internal organs and heat exchange is called basic exchange. At an air temperature of 20 °C, complete rest, on an empty stomach, the basic metabolism is 1 kcal and 1 hour per 1 kg of human body weight. Consequently, basal metabolism depends on body weight, as well as the sex and age of a person (Table 3.1).

To determine a person’s daily energy expenditure, it was introduced physical activity ratio(CFA) is the ratio of total energy expenditure for all types of human life activity with the value of basal metabolism.

The coefficient of physical activity is the main physiological criterion for assigning the population to a particular labor group depending on the intensity of work, i.e. from energy consumption, developed by the Institute of Nutrition of the Academy of Medical Sciences in 1991.

A total of 5 labor groups have been defined for men and 4 for women. Each work group corresponds to a certain coefficient of physical activity (Table 3.2).

For calculation daily energy expenditure the required basal metabolic rate (corresponding to the age and body weight of the person)

Table 3.1

Table of basal metabolic rate of the adult population depending on weight

body, age and gender*

Men (basal metabolic rate), kcal	Women (basal metabolic rate), kcal
Body weight, kg	18...29 years old	30...39 years	40...59 years	60...74 years	Body weight, kg	18...29 years old	30...39 years	40...59 years	60...74 years
				1 180
			1 350			1 150	1 120
		1 500		1 300			1 190	1 160	1 100
				1 360		1 300	1 260	1 220	1 160
						1 380	1 340
		1 720
			1 700	1 570		1 530
			1 780					1 510
									1 500

* Data developed by the Research Institute of Nutrition of the Academy of Medical Sciences and approved by the Chief State Sanitary Doctor on 05/08/1991 No. 5786 - 91.

century) multiplied by the physical activity coefficient (PAI) of a certain population group.

Group I - workers predominantly in mental labor,
very light physical activity, CFA - 1.4: scientific works
nicks, students of humanities, computer operators,
controllers, teachers, dispatchers, control panel workers
nia, medical workers, accounting workers, secretaries, etc. Daily
energy consumption V depending on gender and age is
1800...2450 kcal.

Group II - workers engaged in light work, light physical activity
ical activity, CFA - 1.6: transport drivers, workers
conveyors, weighers, packers, garment workers, workers

Table 3.2 Correspondence of the physical activity coefficient to labor groups

Men	Women
Labor group	KFA	Labor group	KFA
I	1,4	I	1,4
II	1,6	II	1,6
III	1,9	III	1,9
IV	2,2	IV	2,2
V	2,5	V	-

radio-electronic industry, agronomists, nurses, orderlies, workers communications, service industries, industrial sellers govars etc. Daily energy consumption depending on gender and age is 2,100...2,800 kcal.

III group - workers of average labor, average physical
technical activity, KFA - 1.9: mechanics, adjusters, tuners
ki, machine operators, drillers, drivers of excavators, bulldozers,
coal miners, buses, surgeons, textile workers,
shoemakers, railway workers, food sellers, water workers,
apparatchiks, metallurgists, blast furnace workers, chemical plant workers,
catering workers, etc. Daily energy consumption
gii depending on gender and age is 2,500... 3,300 kcal.

IV group - workers of heavy physical labor, high
physical activity, CFA - 2.2: construction workers, according to
drillers, miners, cotton growers, agricultural workers
and machine operators, milkmaids, vegetable growers, woodworkers, metal workers
lurgi, foundry workers, etc. Daily energy consumption depending on
depending on gender and age is 2,850... 3,850 kcal.

Group V - workers of particularly heavy physical labor, very
high physical activity, KFA - 2.5: machine operators and agricultural workers
household workers during sowing and harvesting periods, miners, val
scaffolders, concrete workers, masons, diggers, loaders
mechanized labor, reindeer herders, etc. Daily energy consumption
gii depending on gender and age is 3,750...4,200 kcal.

Control questions

1. What is metabolism?

2. What factors influence metabolism?

3. What is the role of labor and physical education in the metabolic process?

4. How does metabolism occur in people of different ages?

5. What determines a person’s daily energy expenditure?

6. What is basal metabolism?

7. What labor group does the cook belong to? What is her consumption?
energy?

Search Lectures

A person’s energy expenditure is usually divided by unregulated: basal metabolism and specifically dynamic action of food (food thermogenesis), and adjustable: energy expenditure for mental and physical activity.

BX - this is the amount of energy (energy consumption) necessary to maintain vital processes in a person (cellular metabolism, respiration, blood circulation, digestion, internal and external secretion, nerve conduction, muscle tone, etc.) in a state of full physical and psychological rest (for example, sleep) with the exclusion of all endo- and exogenous influences (on an empty stomach or 12-16 hours after a meal, at a comfortable air temperature of 18-20 ° C).

The approximate value of basal metabolic rate (BMR) for persons of average age (35 years), average height (165 cm) and average body weight (70 kg) is 1 kcal (4.186 kJ) per 1 kg of body weight per 1 hour. However, modern research has shown that the basal metabolic rate is not constant even for a given individual and depends on several factors:

- depending on gender and age - in men, the SVR is on average 10% higher than in women. BMR is higher in children than in adults; in older people, basal metabolic rate decreases.

- on height, weight and body composition - an increase in body weight due to fat deposits leads to a decrease in basal metabolism due to the accumulation of inactive tissue. With an increase in muscle mass, basal metabolism increases.

- depending on the time of day, season and climate - when exposed to low temperatures, the basal metabolism increases, when exposed to high temperatures it decreases.

- on the state of health - an increase in BOO in adults is observed in diseases such as malaria, typhoid fever, tuberculosis, diffuse toxic goiter (hyperthyroidism), as well as in conditions accompanied by fever - an increase in body t by 1 ° C leads to increase BOO by 10 - 15 %.. Decreased in hypothyroidism.

The amount of basal metabolism can be determined in a person by direct or indirect measurement methods or by calculation.

— direct measurement (direct calorimetry)— the method consists in directly determining the thermal energy released by a person in a calorimetric chamber. Water flows between the walls of the chamber, which has a constant heat capacity. The amount of heat released is determined by the degree of water heating.

— indirect measurement (indirect calorimetry)- carried out using special recording equipment in a person lying on his back, immediately after waking up, in the morning, on an empty stomach, 12-14 hours after the last meal in a room with an air temperature of 20 ºC. At the same time, oxygen consumption, carbon dioxide release and, for maximum accuracy of determination, the amount of nitrogen excreted in the urine are assessed.

— calculation methods- associated with the use of special tables or formulas. BOO calculation can be carried out according to the Harris-Benedict equation:

BOO ( men) = 66 + 13.7x weight (kg) + 5.0 x height (cm) -6.8 x age (years)

BOO (women) = 655+ 9.6 x weight (kg)+ 1.8 x height (cm) - 4.5 x age (years)

Specific dynamic action of food (SDAP), or food thermogenesis - increased energy metabolism when eating. This energy is spent by the body on the processes of digestion, absorption, transport, metabolism and storage of nutrients.

Proteins have the greatest potential for increasing energy expenditure, increasing BOO by 30 - 40%. When metabolizing fats, BOO increases by 4 - 14%. For carbohydrates, this figure is minimal - 4 - 7%. With a normal mixed diet, the SDDP is 10% of the BOO.

Energy expenditure for mental and physical activity (CPA) - refers to regulated energy consumption . An increase in energy expenditure when performing mental and physical work is called work bonus. Determined according to a special table in kcal/hour for each type of activity,

The amount of the basic exchange, SDDP and work allowance is daily energy consumption.

(CFA) is the ratio of total energy expenditure to the body’s basal metabolism. The higher the body's energy expenditure, the higher the CFA. Total energy expenditure (E day) = Basal metabolism × CFA

Group 1 – persons predominantly engaged in mental work. KFA –– 1.4 (scientists, students of humanities, computer operators, teachers, dispatchers, controllers, control panel workers).

Group 2 – persons engaged in light physical work. CFA –– 1.6 (drivers of trams, trolleybuses, conveyor workers, packers, garment workers, radio-electronic industry workers, agronomists, nurses, orderlies, communication workers, service workers, sellers of manufactured goods).

Group 3 – persons engaged in moderate physical work. KFA –– 1.9 (mechanics, service technicians, excavator and bulldozer operators, bus drivers, surgeons, railway workers, shoemakers, food sellers).

Group 4 – persons engaged in heavy physical labor(builders, tunnelers, milkmaids, metallurgists, foundry workers). CFA for men – 2.3, for women – 2.2.

Group 5 - workers engaged in very heavy physical labor. CFA is equal to 2.5 These are underground miners, steelworkers, timber fellers, masons, concrete workers, diggers, loaders, etc.

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Daily energy consumption consists of 3 main items:1) basal metabolism; 2) specifically dynamic action of nutrients(increase in basal metabolism when recycling the diet by 10-15%) and 3) energy costs for performing various types of human activities during work and rest.

Daily energy consumption can be estimated using laboratory methods (direct and indirect calorimetry, etc.), as well as calculation methods. The most accessible is the calculation method, which allows you to approximately determine daily energy consumption, using special tables that indicate the average energy consumption in kilocalories (kcal) per 1 minute per 1 kg of body weight, taking into account the basal metabolism.

The calculation technology consists of four stages.

First stage — compiling a detailed timeline of human activity for one day (24 hours). Timing should reflect all types of human activity and their duration in minutes for the specified day, including sleep.

Example of timekeeping:

24.00 – 7.30: sleep – 450 min.

7.30 – 8.00: morning exercises – 30 min.

Total: 1440 min. (24 hours)

Second phase — calculation of energy consumption (energy consumption) in kilocalories per 1 kg of human body weight for each type of activity using tables.

Calculation example:

Total: (for example) 36.18 kcal/kg

Third stage — calculation of the amount of total energy consumption taking into account body weight.

Let's say the body weight of this person is 68 kg. Total energy costs will be:

36.18 kcal/kg multiplied by 68 kg = 2460.24 kcal.

Fourth stage — calculation of actual (gross) daily energy consumption (kcal/day), taking into account the specifically dynamic action of nutrients, which increases total energy consumption by an average of 10%.

In this example:

2460.24 + 246.02 = 2706.26 kcal/day

Determination of individual nutritional needs

Substances

It is known (physiologically justified) that 14% of all daily energy expenditure should be provided by dietary proteins, 30% by fats, and 56% by carbohydrates.

The technology for calculating the amount of proteins, fats and carbohydrates required by the body consists of two stages:

first stage — calculation of the amount of energy in kcal that should be released during utilization in the body of: a) proteins; b) fats; c) carbohydrates.

second phase — calculation of the amount of proteins, fats and carbohydrates required by the body in grams.

Calculation example:

First stage. Let's say the daily energy consumption of a given person is 2185 kcal. Of them:

- the share of proteins should be 14 %

2185 kcal - 100% X = kcal

- the share of fats should be 30% . We compose and solve the proportion:

2185 kcal - 100%

X - 30% X = kcal

- carbohydrates should account for 56 % . We compose and solve the proportion:

2185 kcal - 100%

X - 56% X = kcal

Second phase. Knowing the number of calories that should be released when the body utilizes proteins, and taking into account that When 1 gram of protein is burned, 4 kcal are released, we find the individual need of the body for proteins:

305.9 kcal: 4 = 76.475 g protein

Knowing the number of calories that should be released when the body utilizes fats, and taking into account that 1 gram of fat releases 9 kcal when burned, we find the body’s individual need for fats:

655.5 kcal: 9 = 72.83 g fat

Knowing the number of calories that should be released when the body utilizes carbohydrates, and taking into account that when burned, 1 gram of carbohydrate releases 4 kcal, we find the body’s individual need for carbohydrates:

1223.6 kcal: 4 = 305.9 g carbohydrates

Thus, in order for the body to receive 2185 kcal with the diet, it must contain 76.475 g of proteins, 72.83 g of fats and 305.9 g of carbohydrates, while the ratio of proteins, fats and carbohydrates will be 1: 0,95: 4 , i.e. meet the physiological needs of the body.

During the practical lesson, the student must:

— make a detailed timeline of your working day for the previous day and enter its data into the table;

— draw a conclusion on the amount of daily energy consumption in accordance with the existing classification of the severity of labor of the population, taking into account age and gender;

PROTOCOL

student's independent work

1. Calculation of the student’s actual (gross) energy consumption:

Activities	Load duration, min	Energy consumption, kcal/min/kg	Total, Kcal/min/kg
1. Sleep		0,0155
2. Morning exercises		0,0646
3. Dressing, undressing		0,0281
4. Personal hygiene		0,0329
5. Homework		0,0530
6. Cooking		0,0343
7. Eating		0,0236
8. Walking		0,0540
9. Running		0,1780
10. Riding while sitting in public transport		0,0252
11. Riding in public transport while standing		0,0267
12. Taking notes from the lecture		0,0289
13. Practical exercises standing		0,0360
14. Practical exercises while sitting		0,0309
15. Answer on the board		0,0372
16. Work in the operating room		0,0316
17. Caring for adult patients		0,0330
18. Caring for a sick child		0,0310
19. Work on a PC		0,0289
20. Determination of daily energy consumption Driving a car		0,0363
21. Playing sports (on average)		0,2086
22. Reading to yourself		0,0209
23. Reading aloud		0,0250
24. Rest lying down, without sleep		0,0183
25. Rest while sitting		0,0229
26. Preparation for classes		0,0309
27.
28.

Total: minutes = kcal =

Body weight (MT) - ______ kg

Total energy expenditure (TE) = _________ kcal times (BW) _____kg =________ kcal

An increase in basal metabolic rate (BMR) by 10% is _________ kcal

Gross energy consumption is equal to (GE)_________+(POE)_________= ____________kcal/day

2. Calculation of the required amount of proteins, fats and carbohydrates in grams (see the first stage):

proteins__________________________________________ g;

fat_________________________________________________ g;

carbohydrates__________________________________________ g.

Conclusion

Signature Signature

student teacher

Place for calculations and notes

Control questions

1. What is meant by the term “human energy consumption”?

2. What methods do you know for determining human energy expenditure?

3. Which of the existing methods for determining a person’s daily energy expenditure is most often used in practice?

4. What does a person’s daily energy expenditure consist of?

5. What is the “specific dynamic effect of food (or nutrients)”?

6. What is the magnitude of the “specific-dynamic action of food”?

7. What is “basal metabolism”?

8. What is the average “basic metabolic rate” for a woman and a man?

9. What factors influence the amount of “basal metabolism”?

10. How does a person’s age affect the value of “basic metabolism”?

11. How does a person’s gender affect the “basal metabolic rate”?

12. How does ambient temperature affect the value of “basic metabolism”?

13. How does the state of a person’s health affect the value of “basic metabolism”?

14. What hormones increase the “basal metabolic rate”?

15. What hormones reduce the “basal metabolic rate”?

16. In what units is the value of “basic metabolism” assessed?

17. What do you understand by the term “unregulated” energy consumption?

18. What do you understand by the term “regulated” energy consumption?

19. How does his activity affect a person’s energy needs?

20. What is “energy balance”?

21. What is the technology for calculating the actual (gross) daily energy consumption of a person?

22. How much energy is released when the body utilizes one gram of protein?

23. How much energy is released when the body utilizes one gram of fat?

24. How much energy is released when the body utilizes one gram of carbohydrates?

25. What percentage of a person’s daily energy expenditure should be compensated by protein consumption?

26. What percentage of a person’s daily energy expenditure should be compensated by consuming fat?

27. What percentage of a person’s daily energy expenditure should be compensated by consuming carbohydrates?

28. In what units is the energy value of proteins, fats, and carbohydrates estimated?

29. How, knowing a person’s daily energy expenditure, can one calculate the required amount of proteins, fats, and carbohydrates to compensate for these energy expenditures?

30. What groups is the population divided into in the existing classification of labor according to its severity?

31. What principles are included in the existing classification of the population according to the degree of severity of labor?

32. Representatives of which professions make up the first group in the classification of the population according to the degree of severity of work?

33. Representatives of what professions make up the second group in the classification of the population according to the degree of severity of work?

34. Representatives of what professions make up the third group in the classification of the population according to the degree of severity of work?

35. Representatives of what professions make up the fourth group in the classification of the population according to the degree of severity of work?

36. Representatives of which professions make up the fifth group in the classification of the population according to the degree of severity of work?

37. What age groups are the adult working population divided into in the classification of labor according to the degree of its severity, depending on gender?

38. What are the energy expenditures of male and female students?

Methods for determining the body's energy expenditure

Energy exchange processes are based on the laws of thermodynamics, i.e. laws of mutual transformations of various types of energy during its transition from one body to another in the form of heat or work.

From the point of view of thermodynamics, living organisms belong to open stationary nonequilibrium systems. This means that they exchange matter and energy with the environment.

In physiology and medicine, calorimetry methods (direct and indirect), as well as the study of gross metabolism, are used to determine energy production in the body.

Direct calorimetry.

This method is based on direct and complete accounting of the amount of heat generated by the body in biocalorimeters (a sealed and well-insulated chamber from the external environment, in which water circulates through tubes, oxygen is also supplied, and excess carbon dioxide and water vapor are absorbed).

Depending on the degree of heating of the water and its mass, the amount of heat released by the body per unit of time is estimated.

Indirect calorimetry.

Unlike direct calorimetry, indirect calorimetry methods are more convenient and simpler. This technique includes two ways to assess the body’s energy expenditure:

1. Incomplete gas analysis.

2. Complete gas analysis.

Incomplete gas analysis is based on determining the amount of oxygen consumed by the body with subsequent calculation of heat production.

For this purpose, spirometabolograph devices are used. , representing a closed system that consists of a spirometer and a carbon dioxide absorber. A spirogram is recorded in accordance with the breathing rhythm . The height of the slope of the curve corresponds to the amount of oxygen absorbed.

Knowing the volume of oxygen absorbed in 1 minute, the average respiratory coefficient and the corresponding caloric equivalent of oxygen, you can calculate energy exchange for any period of time.

Complete gas analysis is based on determining the volume of carbon dioxide released and the volume of oxygen consumed by the body, followed by calculation of heat production.

To assess the intensity of gas exchange during a complete gas analysis, closed and open systems are used.

In devices of closed systems, the subject inhales air or oxygen from a closed space, and the exhaled air is directed into the same space.

The most common open method for studying heat production is the Douglas-Haldane method. The advantage of this method is the fact that the body’s energy consumption can be determined during any work. The essence of this method is that for 10-15 minutes, exhaled air is collected in a bag made of airtight fabric (Douglas bag), fixed on the back. The subject breathes through a mouthpiece placed in the mouth or a rubber mask placed on the face. The mouthpiece and mask have valves designed so that atmospheric air is freely inhaled and exhaled into the Douglas bag. When the bag is full, the volume of exhaled air is measured, in which the amount of oxygen and carbon dioxide is determined.

Scheme for determining energy costs using the Douglas-Haldane method.

1. At the first stage, after performing a certain work, the amounts of consumed O2 and released CO2 are determined. To do this, it is necessary to establish the concentration of these gases in the Douglas bag. Knowing the content of O2 and CO2 in the atmospheric air, it is possible to calculate how much the oxygen content has decreased and the carbon dioxide content in the exhaled air has increased.

2. Based on the data obtained, the respiratory coefficient is calculated. Respiratory coefficient is the ratio of the volume of released CO2 to the volume of absorbed O2.

DC = CO2 (l) / O2 (l)

The respiratory coefficient (RC) is different during the oxidation of proteins, fats and carbohydrates.

For example, during the oxidation of glucose, the number of molecules of CO2 formed and the number of molecules of absorbed O2 are equal, therefore the DC for carbohydrates is 1.

During the oxidation of fats and proteins, the DC will be below unity. So, during the oxidation of fats it is 0.7, and for proteins 0.8.

With mixed food, DC is 0.8-0.9.

During fasting and diabetes mellitus, due to a decrease in glucose metabolism, the oxidation of fats and proteins increases and DC can decrease to 0.7.

3. For each calculated DC there is a certain caloric equivalent of oxygen (CEC). KEC is the amount of energy that is released during the complete oxidation of 1 g of a nutrient (to final products) in the presence of 1 liter of oxygen (table).

Respiratory quotient ratio

and calorimetric oxygen equivalent

4. The found KEK is multiplied by the amount of oxygen consumed and the amount of energy required to perform a certain type of activity is found.

Respiratory coefficient during muscular work.

The main source of energy during intense muscular work is carbohydrates.

Therefore, during operation, the DC approaches unity. Immediately after finishing work, it can increase sharply. This phenomenon reflects compensatory processes aimed at removing excess CO2 from the body, the source of which is non-volatile acids, which (especially lactic acid) are actively produced by working muscles. These acids bind to plasma buffer systems and displace carbon dioxide from the bicarbonate ion (HCO–3). Thus, the total amount of carbon dioxide released is higher than normal for a short time. Enhanced ventilation of the lungs in these cases prevents the pH of the blood and tissues from shifting to the acidic side.

Some time after completion of work, the DC may sharply decrease compared to the norm. This is due to a decrease in the release of CO2 by the lungs due to its compensatory retention by the blood buffer systems, which prevent a shift in pH towards the main side.

About an hour after the work is completed, the DC becomes normal.

BX

BX– the minimum amount of energy necessary to ensure normal life activity in conditions of relative physical and mental peace. This energy is spent on cellular metabolic processes, blood circulation, respiration, excretion, maintaining a constant body temperature, functioning of vital nerve centers of the brain, constant secretion of endocrine glands, maintaining muscle tone.

Energy consumption at rest by different tissues of the body is not the same. Thus, the liver consumes 27% of the basal metabolic energy, the brain - 19%, muscles - 18%, kidneys - 10%, heart - 7%, all other organs and tissues - 19%. Internal organs consume energy more actively compared to muscle tissue. The intensity of basal metabolism in adipose tissue is 3 times lower than in the rest of the cellular mass of the body.

The dependence of the basal metabolic rate on the body surface area was shown by the German physiologist Rubner for various animals – Rubner's law of body surface... According to this rule, the intensity of the basal metabolic rate is closely related to the size of the body surface: in warm-blooded organisms with different body sizes, the same amount of heat is dissipated from 1 m2 of surface.

Any work - physical or mental, as well as food intake, fluctuations in ambient temperature and other external and internal factors that change the level of metabolic processes, entail an increase in energy expenditure.

Therefore, basal metabolism is determined under strictly controlled, artificially created conditions. To determine the basal metabolic rate, the subject must be:

1. In a state of physical and psychological rest, i.e. in a lying position with relaxed muscles, without being exposed to irritations that cause emotional stress. Under conditions of muscular and mental stress, the intensity of metabolic processes increases.

2. On an empty stomach, i.e. 12-18 hours after eating. The increase in metabolic rate after eating begins after 1-2 hours and can last for 12 hours, and after consuming protein this period can reach 18 hours.

3. At a “comfortable” temperature (18-20°C), which does not cause a feeling of cold or heat.

4. The intensity of metabolic processes is subject to daily fluctuations. It increases in the morning and decreases at night, which also must be taken into account when determining the basal metabolism.

Factors that determine the amount of basal metabolism.

Basic metabolism depends on:

1. Age. With age, the basal metabolic rate steadily decreases. The most intense basal metabolism per 1 kg of body weight is observed in children (in newborns - 53 kcal/kg per day, in children of the first year of life - 42 kcal/kg).

2. Constitutional characteristics of the physique (height, body weight);

3. Paula. The average basal metabolic rate in adult healthy men is about 1700 kcal or 7117 kJ per day; in women it is 10% lower. This is due to the fact that women have less mass and body surface area.

Seasonal fluctuations in basal metabolic rate were noted (increased in spring and decreased in winter).

Methods for determining basal metabolism.

The values ​​of basal metabolism can be calculated using the Dreyer formula, according to which, the daily value of basal metabolism in kilocalories (H) is:

, Where:

W – body weight in grams,

A is the person’s age,

K is a constant equal to 0.1015 for men and 0.1129 for women.

It is also possible to estimate basal metabolic rates using special tables that allow you to determine the average level of a person’s basal metabolic rate based on height, age and body weight.

Formulas and tables of basal metabolic rate represent average data derived from a large number of studies of healthy people of different gender, age, body weight and height, so there are methods that allow you to calculate the deviation of basal metabolic rate from the norm using hemodynamic parameters (Reed's formula). This method is based on the relationship between blood pressure, pulse rate and body heat production.

PO – percentage of deviations;

HR – heart rate;

PP – pulse pressure.

A deviation of ± 10% is considered acceptable.

Work exchange

Working metabolism is the totality of the basal metabolism and energy expenditure of the body, ensuring its vital activity under conditions of thermoregulatory, emotional, nutritional and work loads.

The thermoregulatory increase in the intensity of metabolism and energy develops under cooling conditions and in humans can reach 300%.

During emotions, the increase in energy expenditure in an adult is usually 40-90% of the basal metabolic rate and is associated mainly with the involvement of muscle reactions. Listening to radio programs that cause emotional reactions can increase energy expenditure by 50%; in children, when screaming, energy expenditure can triple.

Working metabolism exceeds basal metabolism, mainly due to the functions of skeletal muscles. With their intense contraction, energy consumption in the muscle can increase 100 times; the total energy consumption with the participation of more than 1/3 of skeletal muscles in such a reaction can increase 50 times in a few seconds. The population of industrialized countries has relatively little daily physical activity, so daily energy consumption is approximately 8000-10500 kJ, or 2000-2250 kcal.

In a sitting position, a person spends only 20% more energy than in a lying position. While standing, a person spends 40% more energy than during basal metabolic conditions. Walking at a speed of at least 5 km/h increases energy consumption by 3-4 times. A daily two-kilometer walk (without changes in diet) can help eliminate 1 kg of fat in 1 month. By increasing energy consumption during physical dynamic loads (fast walking, running, swimming, skiing) at least 3 times a week, you can significantly increase the health reserves of a person as a whole.

During sleep, the metabolic rate is 10-15% lower than during wakefulness, which is due to muscle relaxation, as well as a decrease in the activity of the sympathetic nervous system, a decrease in the production of adrenal and thyroid hormones, which increase catabolism.

Physical activity rate– the ratio of total energy consumption for all types of life activity to the value of basal metabolism, i.e. energy expenditure at rest. This indicator is an objective physical criterion that determines the adequate amount of energy expenditure for specific professional groups of people. The values ​​of the physical activity coefficient are the same for men and women, but due to the lower body weight in women and, accordingly, the basal metabolism, the energy expenditure of men and women in groups with the same physical activity coefficient is different.

Group I. Very light physical activity.

Daily energy expenditure of the body

Physical activity coefficient 1.4. Energy consumption is 1800-2450 kcal/day. This group includes predominantly mental workers (scientists, students of humanities, computer operators, dispatchers, control panel workers, etc.).

Group II. Light physical activity. Physical activity coefficient 1.6. Energy consumption is 2100-2800 kcal/day (workers engaged in light physical labor: tram and trolleybus drivers, conveyor workers, weighers, service workers, nurses, orderlies, etc.).

Group III. Average physical activity. Physical activity coefficient 1.9. Energy consumption is 2500-3300 kcal/day. This group includes workers of moderate labor (mechanics, drillers, bus drivers, surgeons, textile workers, railway workers, metallurgists, blast furnace workers, chemical plant workers, etc.).

Group IV. High physical activity. Physical activity coefficient 2.2. Energy consumption 2850-3850 kcal/day. (hard physical labor workers: construction workers, driller's assistants, tunnelers, the bulk of agricultural workers and machine operators, milkmaids, vegetable growers, woodworkers, metallurgists, etc.).

Group V Very high physical activity. Physical activity coefficient 2.5. Energy consumption is 3750-4200 kcal/day. This group includes workers of particularly hard labor, only men (agricultural workers during the sowing and harvesting periods, miners, timber fellers, concrete workers, masons, diggers, loaders of non-mechanized labor, etc.).

For each labor group, the average values ​​of the balanced needs of a healthy person for energy and nutrients are determined.

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5. Energy exchange

Direct and indirect calorimetry

Metabolism and energy are essentially a single process. As a result of complex transformations taking place in the body, heat is formed.

The amount of energy released by the body over a certain period of time is expressed in units of heat - joules. The amount of energy released in the body can be determined using direct and indirect calorimetry.

Direct calorimetry produced using special devices - calorimetric chambers (Fig. 59).

The walls of the chamber do not conduct heat. A system of water pipes runs along the ceiling of the chamber. A person or animal is placed in such a chamber for a certain time. The heat generated by the body heats the water in the tube system. The temperature of the water entering and exiting the chamber is measured; determine the temperature difference and the amount of flowing water. This makes it possible to obtain data on the amount of energy released by the body per unit of time.

The indicators obtained by direct calorimetry are accurate.

Table of human energy consumption for various types of activities

But this method is very complicated, cumbersome, and most importantly, it does not make it possible to measure the body’s energy expenditure during various types of human activity (riding a bicycle, working at a blast furnace, etc.).

It is easier to calculate energy consumption using the indirect calorimetry.

Rice. 59. Calorimeter circuit. The heat produced by the human body is measured using thermometers (1 and 2) by heating the water flowing through the pipes in the chamber (4). The amount of water flowing is measured in the tank (3). Through the window (5) food is served and excrement is removed. By means of a pump (6), air is removed from the chamber and driven through tanks with sulfuric acid (7 and 9) (to absorb water) and soda lime (8) (to absorb carbon dioxide). Oxygen is supplied to the chamber from a cylinder (10) through a gas clock (11). The air pressure in the chamber is maintained at a constant level by means of a vessel with a rubber membrane (12)

Rice. 60. Determination of gas exchange using a Douglas bag

The source of energy in the body is oxidative processes, in which oxygen is consumed and carbon dioxide is released. The more energy the body releases, the more intense oxidative processes occur in it. Consequently, the more the body consumes oxygen and releases carbon dioxide. Therefore, energy processes in the body can be judged not only by the amount of heat released into the environment, as is done with direct calorimetry, but also by the amount of oxygen absorbed and carbon dioxide released, i.e., by the amount of gas exchange.

To determine the amount of oxygen absorbed and carbon dioxide released, various devices are used. In production and educational settings, masks are used for this purpose.

The mask, through a system of valves, is connected to a bag made of airtight fabric (Fig. 60), which is attached to the body of the test subject. The valves make it possible to freely inhale atmospheric air, and the exhaled air is directed into the bag. The exhaled air from the bag is passed through a gas clock to determine its volume, and then the percentage of oxygen and carbon dioxide in it is determined chemically. Knowing the composition of inhaled and exhaled air, you can calculate the amount of absorbed oxygen and exhaled carbon dioxide.

The oxygen absorbed by the body is used to oxidize proteins, fats and carbohydrates. The oxidation of 1 g of proteins, fats or carbohydrates requires different amounts of oxygen, and therefore different amounts of energy are released (Table 14).

Table 14. Energy generation during the oxidation of substances in the body

From Table 14 it can be seen that the consumption of 1 liter of oxygen and the release of 1 liter of carbon dioxide are accompanied by the formation of a certain amount of energy. However, it is necessary to know which substances - proteins, fats or carbohydrates - have been oxidized in the body. To do this, determine the value of the respiratory coefficient.

The respiratory quotient is the ratio of the volume of carbon dioxide released by the body to the volume of oxygen absorbed. The respiratory coefficient is different during the oxidation of proteins, fats and carbohydrates. The oxidation of carbohydrates (glucose, for example) can be expressed by the equation:

From the equation it can be seen that during the oxidation of glucose, the number of molecules of carbon dioxide formed and oxygen absorbed is equal. Therefore, the respiratory coefficient during the oxidation of carbohydrates is equal to unity:

The fat molecule contains little intramolecular oxygen, so its oxidation requires more oxygen. The respiratory coefficient in this case is less than 1. During the oxidation of proteins, the respiratory coefficient is 0.8. With mixed food, which a person usually eats, the respiratory coefficient ranges from 0.85 to 0.9.

When proteins, fats and carbohydrates are oxidized (with the consumption of 1 liter of oxygen), different amounts of energy are released. Consequently, with different respiratory coefficients, the amount of released energy when absorbing 1 liter of oxygen will be different. This dependence can be seen from Table 15.

Knowing the amount of gas exchange, you can calculate energy consumption in the body. This is how they do it.

Table 15. Dependence of the amount of energy released during oxidation on the value of the respiratory coefficient

The respiratory quotient is determined by the amount of oxygen consumed and carbon dioxide released. Then, using the tables, the amount of heat generated when 1 liter of oxygen is absorbed (or when 1 liter of carbon dioxide is released) at a given respiratory coefficient. The resulting value is multiplied by the number of liters of oxygen absorbed. In this way, the amount of energy given by a person in a certain time is determined.

The method is called indirect calorimetry because we judge the amount of energy released by the body by the amount of oxygen absorbed (or carbon dioxide released) per unit time.

BX

Even in conditions of complete rest, a person expends a certain amount of energy. The body continuously spends energy on physiological processes that do not stop for a minute. Metabolic processes take place in the cells, and a constant body temperature is maintained.

The minimum level of metabolism and energy expenditure for the body is called basal metabolism.

Basal metabolism is determined in a person in a state of muscular rest, lying down, on an empty stomach, i.e. 12-16 hours after eating, at an ambient temperature of 18-20 ° C ("comfort" temperature). In a middle-aged person, the basal metabolism is 4186 J per 1 kg of weight per 1 hour. On average, this is 7,140,000-7,560,000 J per day.

For each person, the basal metabolic rate is relatively constant.

Determining the basal metabolic rate often has diagnostic value. The basal metabolism increases with excessive thyroid function and some other diseases. If the function of the thyroid gland, pituitary gland, or gonads is insufficient, the basal metabolism decreases.

Energy expenditure during muscle activity

The harder the muscular work, the more energy a person spends. For schoolchildren, preparing for a lesson and a lesson at school require energy 20-50% higher than the basal metabolic energy.

During laboratory exercises, manual labor, simple gymnastics, and games of average mobility, energy expenditure is 75-125% higher than the basal metabolic rate.

When walking, energy expenditure is 150-170% higher than the basal metabolic energy. When running or climbing stairs, energy expenditure is three to four times higher than the basal metabolism.

Boys generally have higher energy expenditure than girls. Training the body significantly reduces energy consumption for the work performed. This is due to a decrease in the number of muscles involved in work, as well as changes in breathing and blood circulation.

With the mechanization of labor in agriculture and industry and the introduction of machinery, the energy consumption of working people is reduced. During mental work, energy costs are lower than during physical work.

People of different professions have different energy expenditures.

Energy expenditure in the body can be divided into 2 groups: basal metabolism and additional metabolism. How to calculate them and determine human energy consumption?

The most accurate way to determine the body's energy expenditure is through clinical diagnostics. Currently, to determine energy consumption, in most cases, the method of indirect calorimetry is used to assess basal metabolism and exercise-respiratory calorimetry to obtain information on energy consumption at different stages of physical activity. Modern metabolic analyzers make it possible to determine the body's energy consumption with minimal error. An individual examination of the gastrointestinal tract is also usually carried out, on the basis of which the specific dynamic effect of food can be more accurately determined and the necessary nutritional recommendations can be given. There are a number of other studies that make it possible to most accurately determine the body’s daily need for energy and macronutrients (proteins, fats and carbohydrates), and, accordingly, to most accurately select an individual diet and create an optimal exercise program. We strongly recommend that you consult a professional nutritionist and undergo all necessary examinations to create an optimal weight control program.

For those who don't like doctors.

Based on numerous definitions of basal metabolism in people, tables of average normal values ​​for this indicator have been compiled depending on age, gender and total body surface.

There are also many formulas and methods for determining the average basal metabolic rate (according to Duboys, according to Dreyer, according to Harris-Benedict). Recently, the Mifflin St Jeor technique has gained popularity. There is also the Katch-McArdle formula, which calculates the basal metabolic rate on fat-free body mass. Accordingly, to use it, you need to know your body fat percentage. Whatever method or formula you use, the data obtained will not differ much from the statistical average.

In addition, there is also such a concept as the specific dynamic action of food (SDA) - the body’s energy costs associated with the consumption and digestion of food. The average figure for DDI is 10% of the basal metabolism.

After calculating the main exchange rate, it is necessary to determine the additional exchange rate. There is an average classification of additional metabolic values ​​depending on professional activity or physical activity, which is usually called the physical activity coefficient.

For example, the formulas for calculating the basic metabolic rate using the Mifflin-San Jeor method look like this:

• Men: 10 x weight (in kg) + 6.25 x height (in cm) – 5 x age (in years) + 5
• Women: 10 x weight (in kg) + 6.25 x height (in cm) – 5 x age (in years) – 161

By calculating the average statistical value of the main metabolism, you can calculate the amount of additional metabolism. To do this, multiply the resulting number by the physical activity coefficient.

Physical activity rates:

1. Minimum load (knowledge workers, sedentary work) = 0.2
2. Some daily activity or light exercise 1-3 times a week = 0.375
3. Moderate work or training 4-5 times a week = 0.4625
4. Intense training 4-5 times a week = 0.550
5. Daily training = 0.6375
6. Daily intense training or training twice a day = 0.725
7. Heavy physical work or intense training 2 times a day = 0.9

For example, let’s calculate the energy consumption for a female manager whose age is 35 years, height – 166 cm and weight 65 kg.
Basal metabolic rate = (10 x 65) + (6.25 x 166) – (5 x 35) – 161 = 1351.5
Specific dynamic effect of food = 135.15
Additional exchange = (1351.5 + 135.15) x 0.375 = 557.49
So: average daily energy consumption = 1351.5 + 135.15 + 557.5 = 2044.15

To find out the norm that will ensure weight loss, you need to subtract 10 - 30% from the resulting amount.
30% of 2044.15 = 613.245
2044,15 – 613,245 = 1430,9

The lower limit of the daily calorie intake beyond which you absolutely cannot fall can be calculated using the formula:
Weight (in grams)/450*8
65000 / 450 x 8 = 1155.5

Organizing meals to constantly maintain a given calorie limit is quite difficult, so if you independently calculate and prepare your diet, determine the calorie corridor.
Calories for weight loss - 200 = low end of range
Calories for weight loss + 100 = upper range limit
For comfortable weight loss and to avoid breakdowns, it is not recommended to reduce the caloric content of the daily diet below 1200 kcal and it is strictly forbidden to reduce the caloric content of food below the daily calorie limit. In our example, this is 1150 kcal, so if your lower limit is below 1200, you need to burn extra calories through physical activity.

We have already mentioned a clinical diagnostic method - stress respiratory calorimetry, with which you can obtain information about individual energy consumption at different stages of physical activity.

Based on many observations and measurements, the average statistical values ​​of energy consumption for various physical activities were determined.

Methods for determining daily energy consumption

You can find a table with these values ​​here (link).

Multiply your basal metabolic rate by the average coefficient from the table, divide the resulting value by 24 (hours per day) and multiply by the time spent on the selected activity.

For example:

A woman's basal metabolic rate is calculated at above 1351.5. Let's calculate the costs for slow walking, walking for 1 hour. The coefficient of this type of physical activity = 2.7, respectively: 1351.5 x 2.7 / 24 x 1 = 152

When drawing up a plan and schedule for physical activity, pay attention not only to the calories burned, but also to ensure that the exercises bring you pleasure and in no case overload the cardiovascular and nervous systems, muscles, bones and ligaments. If you want to determine the optimal load yourself, we recommend: first of all, listen to your body and its reactions; if you feel discomfort and pain, this is a serious reason for correcting the program. And secondly, you should increase the intensity of exercise gradually, giving the body the opportunity to get used to the new way of life. A sharp increase in loads can harm an unprepared body and will most likely cause hostility on a psychological level. We also recommend that you monitor your heart rate or, scientifically speaking, your heart rate (HR). Constantly monitoring your heart rate will not only prevent fatigue and injury, but will also allow you to avoid spending hours training half-heartedly.

You can determine your body's optimal heart rate using clinical diagnostics of the cardiovascular system. We also strongly recommend consulting with a professional fitness trainer to create an optimal plan and schedule for physical activity.

You can see the average heart rate data for people with poor physical fitness in the table:

Age	Bottom line	Upper limit
Up to 30	110	120
31-40	100	110
41-50	90	100
51-60	80	90

In the next article we will try to write how to calculate the energy entering the body and create a balanced nutrition plan.

To provide a person with food that corresponds to his energy expenditure and plastic processes, it is necessary to determine the daily energy consumption. The unit of measurement for human energy is the kilocalorie.

During the day, a person spends energy on the work of internal organs (heart, digestive system, lungs, liver, kidneys, etc.), heat exchange and performing socially useful activities (work, study, household work, walks, rest). The energy expended on the functioning of internal organs and heat exchange is called basal metabolism. At an air temperature of 20° C, complete rest, on an empty stomach, the main metabolism is 1 kcal per 1 hour per 1 kg of human body weight. Therefore, basal metabolism depends on body weight, as well as the sex and age of a person.

Table of basal metabolic rate of the adult population depending on body weight, age and gender

Men (basal metabolic rate), kcal					Women (basal metabolic rate), kcal
Body weight, kg					Body weight, kg
	1450 1520 1590 1670 1750 1830 1920 2010 2110	1370 1430 1500 1570 1650 1720 1810 1900 1990	1280 1350 1410 1480 1550 1620 1700 1780 1870	1180 1240 1300 1360 1430 1500 1570 1640 1720		1080 1150 1230 1300 1380 1450 1530 1600 1680	1050 1120 1190 1260 1340 1410 1490 1550 1630	1020 1080 1160 1220 1300 1370 1440 1510 1580	960 1030 1100 1160 1230 1290 1360 1430 1500

To determine a person’s daily energy expenditure, the coefficient of physical activity (PFA) was introduced - this is the ratio of total energy expenditure for all types of human activity with the value of basal metabolism.

The physical activity coefficient is the main physiological criterion for assigning the population to a particular labor group depending on the intensity of work, i.e. on energy consumption, developed by the Institute of Nutrition of the Academy of Medical Sciences in 1991.

Physical activity coefficient KFA

Labor group		Labor group

A total of 5 labor groups have been defined for men and 4 for women. Each work group corresponds to a certain physical activity coefficient. To calculate daily energy consumption, it is necessary to multiply the basal metabolic rate (corresponding to the person’s age and body weight) by the physical activity coefficient (PFA) of a certain population group.

Group I - workers predominantly in mental labor, very light physical activity, KFA-1,4: scientists, students of humanities, computer operators, controllers, teachers, dispatchers, control panel workers, medical workers, accounting workers, secretaries and etc. Daily energy consumption, depending on gender and age, is 1800-2450 kcal.

Group II - workers engaged in light labor, light physical activity, KFA-1.6: transport drivers, conveyor workers, weighers, packers, garment workers, radio-electronic industry workers, agronomists, nurses, orderlies, workers communications, service industries, sellers of manufactured goods, etc. Daily energy consumption, depending on gender and age, is 2100-2800 kcal.

Group III - workers of moderate labor, average physical activity, KFA-1.9: mechanics, adjusters, adjusters, machine operators, drillers, drivers of excavators, bulldozers, coal combines, buses, surgeons, textile workers, shoe makers, railway workers, food sellers, water workers, apparatchiks, blast furnace metallurgists, chemical plant workers, catering workers, etc. Daily energy consumption, depending on gender and age, is 2500-3300 kcal.

Group IV - workers of heavy physical labor, high physical activity, KFA-2,2: construction workers, driller's assistants, tunnelers, cotton pickers, agricultural workers and machinists, milkmaids, vegetable growers, woodworkers, metallurgists, foundry workers, etc. Daily energy consumption, depending on gender and age, is 2850-3850 kcal.

Group V - workers of particularly heavy physical labor, very high physical activity, KFA-2.4: machine operators and agricultural workers during the sowing and harvesting periods, miners, timber fellers, concrete workers, masons, diggers, loaders of non-mechanized labor, reindeer herders and etc. Daily energy consumption, depending on gender and age, is 3750-4200 kcal.

The daily energy expenditure of a healthy person significantly exceeds the value of the basal metabolism and consists of the following components: basal metabolism; working increase, i.e. energy costs associated with performing a particular job; specific dynamic action of food (protein foods increase metabolic rate by 25-30%, and carbohydrates and fats by 10% or less).

The totality of the components of daily energy expenditure is working exchange . The degree of energy expenditure during various physical activities is determined by the physical activity coefficient - the ratio of the total energy expenditure for all types of activity per day to the value of the basal metabolic rate. According to this principle, the entire population is divided into 5 groups (table).

Groups of workers by energy consumption

For people doing light work while sitting, approximately 2400-2600 kcal per day is needed; those working with greater muscle load require 3400-3600 kcal; those performing heavy muscular work - 4000-5000 kcal and above. In trained athletes, during short-term intense exercise, the amount of working metabolism can be 20 times higher than the basal metabolism.

Oxygen consumption during physical activity does not reflect the total energy expenditure, since part of it is spent on glycolysis (anaerobic) and does not require oxygen consumption. The difference between the need for O 2 and its consumption is the energy obtained as a result of anaerobic decomposition and is called oxygen debt . O2 consumption remains high even after the end of muscular work, since at this time the oxygen debt is returned. Oxygen is spent on converting the main by-product of anaerobic metabolism - lactic acid into pyruvic acid, on phosphorylation of energy compounds (creatine phosphate) and restoration of O 2 reserves in muscle myoglobin.

During mental work, energy consumption also occurs, especially if mental activity is accompanied by emotional arousal. Thus, experienced emotional arousal can cause an increase in metabolism by 11-19% over the next few days.

Metabolism

Metabolism begins with the entry of nutrients into the gastrointestinal tract and air into the lungs. It is carried out in several stages:

1) enzymatic processes of the breakdown of proteins, fats and carbohydrates into water-soluble amino acids, mono- and disaccharides, glycerol, fatty acids and other compounds, occurring in various parts of the gastrointestinal tract, as well as the absorption of these substances into the blood and lymph.

2) transport of nutrients and oxygen by blood to tissues and those complex chemical transformations of substances that occur in cells. They simultaneously carry out the breakdown of nutrients to the final products of metabolism, the synthesis of enzymes, hormones, and components of the cytoplasm. The breakdown of substances is accompanied by the release of energy, which is used for synthesis processes and ensuring the functioning of each organ and the organism as a whole.

3) removal of final decay products from cells, their transport and excretion by the kidneys, lungs, sweat glands and intestines.

The transformation of proteins, fats, carbohydrates, minerals and water occurs in close interaction with each other. The metabolism of each of them has its own characteristics, and their physiological significance is different, therefore the metabolism of each of these substances is usually considered separately.

Protein metabolism

Proteins are used primarily as plastic materials in the body. The need for protein is determined by the minimum amount that will balance its loss by the body. Proteins are in a state of continuous exchange and renewal. From amino acids obtained during the digestion process, proteins specific for a given type of organism and for each organ are synthesized. Ten of the 20 amino acids (valine, leucine, isoleucine, lysine, methionine, tryptophan, threonine, phenylalanine, arginine and histidine) cannot be synthesized in the body if they are insufficiently supplied from food and are called irreplaceable. Other ten amino acids (replaceable) can be synthesized in the body. Some amino acids are used as energy material, i.e. undergo splitting.

The amount of protein that has undergone decomposition per day is judged by the amount of nitrogen excreted from the human body. 100 g of protein contains 16 g of nitrogen. Thus, the release of 1 g of nitrogen by the body corresponds to the breakdown of 6.25 g of protein. About 3.7 g of nitrogen is released from the body of an adult per day, i.e. the mass of destroyed protein is 3.7 x 6.25 = 23 g, or 0.028-0.075 g of nitrogen per 1 kg of body weight per day (Rubner wear coefficient). E If the amount of nitrogen entering the body with food is equal to the amount of nitrogen excreted from the body, then the body is in a state nitrogen balance. If more nitrogen enters the body than is excreted, this indicates positive nitrogen balance . It occurs when the mass of muscle tissue increases (intense physical activity), during the period of growth of the body, pregnancy, during recovery after a serious illness. A condition in which the amount of nitrogen excreted from the body exceeds its intake into the body is called negative nitrogen balance. It occurs when eating incomplete proteins, when the body does not receive any of the essential amino acids, during protein or complete starvation.

It is necessary to consume at least 0.75 g of protein per 1 kg of body weight per day, which for an adult healthy person weighing 70 kg is at least 52.5 g of complete protein. For reliable stability of nitrogen balance, it is recommended to take 85-90 g of protein per day with food. For children, pregnant and lactating women, these standards should be higher.

Lipid metabolism

Lipids are esters of glycerol and higher fatty acids. Lipids play an energetic and plastic role in the body. Fat oxidation provides about 50% of the adult body's energy needs. Fats serve as a reserve of nutrition for the body; their reserves in humans average 10-20% of body weight. Of these, about half are located in the subcutaneous fatty tissue, a significant amount is deposited in the greater omentum, perinephric tissue and between the muscles. In a state of hunger, when the body is exposed to cold, during physical or psycho-emotional stress, intensive breakdown of stored fats occurs. Under resting conditions, after a meal, resynthesis and deposition of lipids occurs in the depot. The main energetic role is played by neutral fats - triglycerides, and the plastic role is played by phospholipids, cholesterol and fatty acids, which serve as structural components of cell membranes, are part of lipoproteins, and are precursors of steroid hormones, bile acids and prostaglandins.

Lipid molecules absorbed from the intestine are packaged in epithelial cells into transport particles (chylomicrons), which enter the bloodstream through the lymphatic vessels. Lipid molecules can also be synthesized in the body, with the exception of unsaturated linoleic, linolenic and arachidonic fatty acids, which must be obtained from food. These essential acids . The absence or insufficient intake of essential fatty acids in the body leads to growth retardation, impaired renal function, skin diseases, and infertility.

Since cholesterol and triglycerides are hydrophobic compounds, insoluble in blood plasma, in the liver, lipoproteins (fatty substances associated with proteins) are formed for their transport, which differ from each other in size, composition and physicochemical properties. There are three main groups of lipoproteins: very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL).

HDL are small particles that contain many phospholipids and proteins, their function is to remove excess cholesterol from the vascular wall and other tissues. After being saturated with cholesterol, they return to the liver, where cholesterol and its esters are converted into bile acids and excreted in bile. HDL reduces the formation of oxidized forms and is considered the only antiatherogenic (i.e., preventing the development of atherosclerosis) class of lipoproteins. In addition, high-density lipoprotein cholesterol esters are used for the synthesis of steroid hormones in the adrenal glands.

Carbohydrate metabolism

Carbohydrates are the main source of energy and also perform plastic functions in the body; during the oxidation of glucose, intermediate products are formed - pentoses, which are part of nucleotides and nucleic acids. Glucose is necessary for the synthesis of some amino acids, the synthesis and oxidation of lipids and polysaccharides.

The human body receives carbohydrates mainly in the form of the plant polysaccharide starch and in small quantities in the form of the animal polysaccharide glycogen. In the gastrointestinal tract, they are broken down to the level of monosaccharides (glucose, fructose, lactose, galactose). Monosaccharides, the main one of which is glucose, are absorbed into the blood and enter the liver through the portal vein. Here fructose and galactose are converted into glucose. The intracellular concentration of glucose in hepatocytes is close to its concentration in the blood. When excess glucose enters the liver, it turns into a reserve form of its storage - glycogen. The amount of glycogen in an adult can be 150-200 g. In case of restricting food intake, when the level of glucose in the blood decreases, glycogen is broken down and glucose enters the blood. During the first 12 hours or more after eating, maintaining blood glucose concentrations is ensured by the breakdown of glycogen in the liver. After glycogen reserves are depleted, the synthesis of enzymes that provide the reactions of gluconeogenesis - the synthesis of glucose from lactate or amino acids - increases. On average, a person consumes 400-500 g of carbohydrates per day, of which usually 350-100 g is starch, and 50-100 g is mono- and disaccharides. Excess carbohydrates are stored as fat.

Lesson No. 3.

Subject:Physiology and pathophysiology of metabolism and energy

Target: develop the ability to determine energy consumption and calculate energy consumption, analyze food intake and motor activity.

Tasks:

systematize knowledge about basic and general metabolism;

develop the ability to determine a person’s daily energy consumption depending on work activity;

develop the ability to calculate energy consumption;

familiarize yourself with the basic principles of compiling and assessing the diet and develop the ability to analyze the diet;

develop the ability to analyze research results;

contribute to the formation of motivation in students for a healthy lifestyle and its implementation.

Materials and equipment: tables with energy consumption standards for various types of activities, including for athletes, a sample menu layout, tables of the chemical composition of food products, a table of the approximate energy value of individual dishes, a table of the mass of the most commonly consumed foods, a table of daily requirements for basic nutrients and energy , calculator.

Questions for self-study

The concept of metabolism and energy. Basic and general metabolism.

General manifestations of metabolic disorders.

Protein metabolism and its regulation. Disorders of protein metabolism.

Lipid metabolism and its regulation. Violation of fat metabolism.

Carbohydrate metabolism and its regulation. Disorders of carbohydrate metabolism.

Exchange of water and mineral salts, regulation. Violation of the exchange of water and mineral salts.

Interrelation of metabolisms.

Physiological basis of nutrition.

List of laboratory works

Work No. 1. Determination of daily energy consumption.

Work No. 2. Determination of daily caloric intake.

Literature: 1, 2, 6, 7, 9.

Laboratory works

Job No. 1.Determination of daily energy consumption.

Task: determine daily energy consumption using a time-table method and compare the results with hygienic standards for daily energy consumption for people of different professional backgrounds, assess the intensity of the motor regime.

Theoretical background

The total daily energy expenditure consists of the value of the basal metabolism, the work increase, and the energy for the specific dynamic effect of food. The basal metabolic rate is the minimum level of metabolism and energy expenditure. Throughout the day, a person performs different types of work, spending unequal amounts of energy. In this regard, the type of work determines the total energy expenditure of the body.

The timekeeping-tabular method is based on timing, i.e. the time (in minutes) spent on performing various activities during the day.

Modern literature provides hygienic standards for daily energy consumption for people of different professional backgrounds:

Group I– knowledge workers: heads of enterprises, doctors (except surgeons), teachers, scientists, writers, workers in the printing industry, journalists, students.

Daily energy consumption is 2550–2800 kcal for men, 2200–2400 kcal for women, i.e., on average 40 kcal/kg body weight;

Group II– workers of light physical labor (automated line workers, garment workers, agronomists, veterinarians, nurses, sellers of manufactured goods, trainers, physical education instructors).

Daily energy consumption is 3000–3200 kcal for men and 2550–2700 kcal for women; on average 43 kcal;

III group– workers of moderate labor (drivers, surgeons, food industry workers, food sellers, water transport workers).

Daily energy consumption is 3200–3650 kcal (men) and 2600–2800 kcal (women), per 1 kg of weight on average 46 kcal;

IV group– workers of heavy physical labor (builders, agricultural workers, machine operators, metallurgists, athletes).

Daily energy consumption is 3700–4250 kcal (men) and 3150–2900 kcal (women), 53 kcal/kg body weight;

Group V– persons performing particularly heavy physical labor (steelworkers, lumberjacks, miners, loaders).

Daily energy consumption is 3900–4300 kcal in men (61 kcal/kg); for women this consumption is not standardized. The above energy consumption figures

aimed at men and women of average weight (70 kg and 60 kg, respectively).

For persons 60–74 years old, the average daily energy consumption is 2300 kcal (male), 2100 kcal (female), over 75 years old - 2000 kcal (male) and 1900 kcal (female).

For people involved in sports professionally, there are other standard values ​​of daily energy expenditure, specified by type of sport.

The amount of human muscular effort is one of the factors that makes up a healthy lifestyle, since it is a stimulator of the activity of all organs and systems. The amount of muscle activity in a person can be:

optimal (corresponding to the biological needs of the body);

excessive (hyperkinesia, hyperdynamia)

insufficient (hypokinesia, physical inactivity).

Naturally, a person with an optimal motor mode can have sufficient health reserves.

Work order

Enter into the table in order of priority the types of activities carried out during the previous day, starting in the morning (table 1, column 1).

Indicate the time interval for completing each type of work (Table 1, column 2).

Energy consumption per 1 kg of weight per 1 minute (column 4 of table 1) is determined according to the data in tables 2 and 3 in accordance with the type of activity.

Multiply the total energy consumption figure (column 5 of Table 1) by body weight, thus obtaining daily energy consumption.

Taking into account the existence of inaccuracies in the calculation method, 15% (unaccounted energy costs) of daily consumption should be added to the resulting figure. To do this, the value obtained in step 5 must be multiplied by 0.15, and then the value of daily energy consumption and unaccounted energy expenditure must be summed up.

Enter the data into the table of the final minutes of the lesson.

Table 1 - Determination of daily energy consumption

Types of activities per day	Time from...to	Activity time in min	Energy consumption per 1 kg per 1 min	Energy consumption during activity
				0.0648x20=0.1296
				0.0155x480=7.44

Job№ 2. Determination of daily caloric intake.

Task: draw up a table of your own daily menu for meals (select the day with the most typical diet) and determine the daily calorie intake, get acquainted with the basic principles of compiling and assessing the diet.

Theoretical background

Of great interest is the study of the relationship between the amount of energy supplied with food and released into the external environment. This is the so-called energy balance of the body, the study of which provides material for calculating human diets.

Food contains substances that supply the body with energy (fats and carbohydrates) and building materials (proteins), as well as mineral salts and vitamins. If the body receives an insufficient amount of food for a long time (undernutrition) or receives an excess of energy-rich foods (overeating), we should talk about malnutrition. In order for the diet to be adequate and stabilized, these components must be present in the correct proportions. Rational nutrition should ensure normal functioning of the body, high performance, and in children - correct development.

When compiling a diet, one should take into account the correspondence of the caloric content of the diet to the daily energy expenditure, as well as the optimal amount of proteins, fats and carbohydrates for people of this type of work. To determine their percentage in food and the calorie content of 100 g of products, special tables are used.

To determine the daily calorie intake, there are various methods: laboratory, menu layout (calculated).

The laboratory method is used for the appropriate assessment of nutrition in the laboratory of a sanitary and epidemiological station, where, using special techniques, the content of nutrients in food samples taken in canteens, restaurants, cafes in the required quantities in special dishes is determined chemically. It is taken into account that food proteins and carbohydrates supply the body with 4.1 kcal per 1 g, and fats - 9.3 kcal / g.

The most convenient for educational purposes is menu layout method. To do this, fill out the table of your own nutrition according to the sample below (Table 4).

The tables of the chemical composition of food products (Tables 5, 6) provide figures per 100 g of product. It is necessary to recalculate the amount actually consumed.

Work order

Make a table of your own menu in accordance with the sample (Table 4).

Break the dish down into its constituent products, which should be expressed in grams (Table 4, columns 1 and 2, auxiliary table 7).

Break down each product according to all the nutrients it contains, based on the amount of product consumed.

Note: when consuming products in original packaging, copy the calorie content and nutritional content information from those indicated on the label.

Convert the values ​​in column 6 (per 100 g) to the actual amount consumed in column 7.

Calculate in columns the total consumption of all nutrients (proteins, fats, etc.) and calories per day.

Compare the values ​​obtained in step 4 with the standard ones (Table 8).

Calculate energy distribution across meals using your menu table.

Table 4 – Sample menu layout

Name of meals, products and dishes	Quantity, g	Main nutrients, g			Calorie content, kcal	Total calorie content, kcal
				Carbohydrates
Bread with cheese
White bread
Tea with sugar

Decorfinal protocol of lesson No. 3.

Subject: …

Target: …

Materials and equipment: ...

Job No. 1. ...

Work No. 2. ...

Current results are noted and calculations are recorded.

Table - Results of determining energy consumption and calculating energy consumption, analyzing the diet and physical activity

Conclusion: make a general conclusion about the degree of correspondence between energy consumption and energy consumption and the activity of the motor mode.

If there are significant discrepancies, make recommendations for correcting energy consumption (motor mode) and optimizing nutrition.

Questions for self-control

What is called basal metabolism, on what factors does its level depend?

What is called general exchange? What is it made of?

What factors can cause excess body weight?

Table 5

Note. Legend: 0 – absence of a nutrient, determined analytically; “–” – lack of information on nutrient content; Sl. (traces) – the presence of a food substance in quantities of no practical importance; "*" – foreign data; "°" sign – insufficient reliable data; numbers in brackets are data obtained by calculation.

Table 6

Table 7