Physical composition of food and daily energy expenditure. Determination of daily energy consumption
To provide a person with food corresponding to his energy costs 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 apparatus, lungs, liver, kidneys, etc.), heat exchange and the performance of socially useful activities (work, study, housework, walking, rest). The energy expended on the work of internal organs and heat transfer is called the main exchange. 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, the basal metabolism depends on body weight, as well as on the sex and age of the person.
Table of basic metabolism of the adult population depending on body weight, age and sex
|
Men (basic metabolism), kcal |
Women (basic metabolism), 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 the daily energy consumption of a person, the coefficient of physical activity (CFA) was introduced - this is the ratio of total energy consumption for all types of human life with the value of basal metabolism.
The coefficient of physical activity is the main physiological criterion for attributing the population to one or another labor group depending on the intensity of labor, i.e. from energy costs, developed by the Institute of Nutrition of the Academy of Medical Sciences in 1991.
CFA Physical Activity Index
|
Labor group |
Labor group |
||
In total, 5 labor groups are defined for men and 4 for women. Each work group corresponds to a certain coefficient of physical activity To calculate the daily energy consumption, it is necessary to multiply the basal metabolic rate (corresponding to the age and body weight of a person) by the coefficient of physical activity (CFA) of a certain population group.
Group I - predominantly mental workers, very light physical activity, CFA-1.4: scientists, students of humanitarian specialties, 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 work, light physical activity, CFA-1.6: transport drivers, conveyor workers, weighers, packers, garment workers, workers in the radio electronics industry, agronomists, nurses, nurses, workers communications, services, sellers of manufactured goods, etc. Daily energy consumption, depending on gender and age, is 2100-2800 kcal.
Group III - workers of moderate labor intensity, average physical activity, CFA-1.9: locksmiths, adjusters, adjusters, machine operators, drillers, drivers of excavators, bulldozers, coal combines, buses, surgeons, textile workers, shoemakers, railroad workers, food sellers, water workers, apparatchiks, blast-furnace metallurgists, chemical plant workers, public 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, CFA-2.2: construction workers, assistant drillers, sinkers, cotton growers, agricultural workers and machine operators, milkmaids, vegetable growers, woodworkers, metallurgists, foundry workers, etc. Daily energy consumption, depending on gender and age, is 2850-3850 kcal.
Group V - workers of especially hard physical labor, very high physical activity, CFA-2.4: machine operators and agricultural workers during the sowing and harvesting periods, miners, fellers, concrete workers, masons, diggers, loaders of non-mechanized labor, reindeer herders and etc. Daily energy consumption depending on sex and age is 3750-4200 kcal.
The daily energy consumption of a person depends on the nature and intensity of the work performed, age and gender. Calculation of daily energy consumption makes it possible to determine the physiological need of the body for the main nutrients and use them to assess the adequacy of individual nutrition.
Objectives of the lesson.
The goal (general) is to be able to determine the daily energy consumption by the time-table method and calculate the body's need for nutrients.
To achieve a common goal, you need to be able to:
1. Substantiate the energy balance in the body, its disturbances and the body's need for energy.
2. Choose methods for determining daily energy consumption.
3. Carry out the timing of the day.
6. Substantiate the possibility of assessing the adequacy of nutrition by calculation methods.
Theoretical questions on the basis of which it is possible to carry out target activities:
1. The concept of energy balance in the human body.
2. Components of the daily energy consumption of the human body.
a) Basic metabolism, specific dynamic action of food, their characteristics.
b) Energy consumption for various activities, their dependence on the coefficient of physical activity.
3.Methods for determining the daily energy consumption of a person, their characteristics.
4. Time-table method, method of calculating daily energy consumption by the time-table method.
5. Determination of the physiological need of the body for proteins, fats, carbohydrates.
6. Substantiation of the possibility of assessing the adequacy of nutrition by calculation methods.
Literature on the topic
Mandatory:
1.Datsenko I.I., Gabovich R.D. Preventive medicine. Zagalna hygiene with the basics of ecology. Primary help.-K.: Health, 1999. - S. 313-320.
2. Datsenko I.I., Denisyuk O.B., Doloshitsky S.L. Zagalna hygiene: a guide for practical activities. - Lviv: Svіt, 2001. - P. 140 - 146.
3. Lecture on the topic.
4. Graph of the logical structure (Appendix 1).
5. Tutorial.
Additional:
1. Gabovich R.D., Poznansky S.S., Shakhbazyan G.Kh. Hygiene. - K .: Vishcha school, 1983. - S. 134 - 135.
2. Rumyantsev G.I., Vishnevskaya E.P., Kozlova T.A. General hygiene. - M.: Medicine, 1985. - S. 34 - 40.
3. Pivovarov Yu.P., Goeva O.E., Velichko A.A. Guide to laboratory studies in hygiene. - M.: Medicine, 1983. - S. 4 - 12.
1. When studying the energy balance, it is necessary to evaluate three main components: energy intake from food, its reserves in the body and energy costs. The intake of energy in the human body with food is regulated by a complex system, including such physiological manifestations as appetite and satiety, as well as changes in the concentrations of various metabolic substrates in the blood. The adequacy of the energy intake also depends on the degree of absorption and utilization of the energy components of the food. Energy reserves in the body itself depend on body fat, as well as the content of proteins, fats, carbohydrates in body tissues. Energy costs are associated with the maintenance of the physiological functions of the body, due to the work of various body systems - nervous, cardiovascular, respiratory, digestive, excretory, as well as with various activities.
Energy balance is the state of the body in which energy costs are fully covered, that is, the amount of energy produced in the body corresponds to energy costs.
With inadequate nutrition, a negative energy balance can occur in the body, while the energy costs incurred are not covered. The body mobilizes all resources for maximum energy production, which will be accompanied by the waste of tissue nutrients to cover the energy deficit. For energy purposes, protein is consumed, not only from food, but also tissue protein. Negative energy balance is associated with protein deficiency and should be considered as a single complex of protein-energy deficiency. No less harmful is the positive energy balance. It occurs when the energy value of the diet exceeds the energy expenditure by the body for a long time. On the basis of a long-term positive energy balance, overweight, obesity, atherosclerosis, hypertension, coronary artery disease progress and develop to a large extent.
Thus, both negative and positive energy balance adversely affect the state of the body. It is necessary to ensure energy balance, that is, the correspondence between the intake and expenditure of energy by the body during the day.
There is a need to determine the daily energy consumption of each individual.
2. Daily human energy consumption includes 3 components: basal metabolism, specific dynamic action of nutrients (SDA) and energy consumption for various activities.
Energy consumption for basic metabolism and the specific dynamic effect of food should be attributed to energy expenditures that are not regulated by the will of a person, and energy consumption in the process of work, household and home behavior, while playing sports and other activities, is classified as regulated energy consumption.
A) The main metabolism should be understood as the energy exchange necessary to maintain the physiological functions (respiratory muscles, heart, liver, kidneys, etc.) that support the vital activity of the body in a state of complete muscular and nervous rest, 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 the basal metabolism for middle-aged (35 years), average height (165 cm) and average body weight (70 kg) is 1 kcal (4.186 kJ) per 1 kg of weight per 1 hour. The basal metabolic rate is higher in children than in adults, in men it is 10% higher than in women. In the elderly, the basal metabolic rate decreases.
Modern research has shown that the basal metabolic rate is not constant even for a given individual. Basal metabolism reflects hormonal processes in the body, which depend on muscle mass, body weight, the pathological state of internal organs, and endocrine diseases. An increase in body weight due to body fat leads to a decrease in basal metabolism due to the accumulation of little active tissue. A correlative dependence between the value of the basic metabolism and the development of muscles has been established. With an increase in muscle mass, basal metabolism increases.
With limited nutrition and insufficient content in the diet of certain nutrients, the basal metabolism is reduced by 20-40%.
Significant changes in basal metabolism occur when the functions of individual organs and systems are impaired. With such diseases as malaria, typhoid fever, tuberculosis, Graves' disease - the main metabolism is increased; with myxedema - reduced.
The basic metabolism changes depending on the season of the year and climatic conditions, which is due to changes in the hormonal functions of the body. At low temperatures, basal metabolism increases, at high temperatures it decreases.
The specific dynamic action of food (thermogenic action) is the increase energy metabolism when eating. This energy is spent by the body on the processes of digestion, absorption, transport, metabolism and storage of digested food. A weak specific dynamic effect of food is distinguished (increase in energy metabolism by 10%), sufficient (increase from 10% to 20%) and well pronounced (more than 20%). Proteins have the highest DDS (on average 26.8%), carbohydrates have the lowest (2.8%), and fats (8.9%) are in the middle. When taking a mixed meal, the SDD is 10-15% of the basal metabolism.
B) The increase in energy consumption in the performance of mental and physical work is called a work allowance. The work allowance is calculated on the basis of the timing of all activities, taking into account the time spent on each activity. According to a special table, the value of energy consumption in kcal / hour for each type of activity is determined, which will be a working allowance. The sum of working allowances will be the energy consumption for various activities in kcal and kJ per hour.
Work allowances reflect regulated expenditures of energy, which, depending on the conditions and the will of the person, can increase or decrease.
The sum of the basic exchange, DDS and the working allowance is the daily energy consumption.
CFA is the ratio of total energy expenditure to basal metabolic rate.
In accordance with the CFA, the entire working population is divided into the following groups:
Group 1 - persons predominantly mental labor. CFA - 1.4 (scientists, students of humanitarian specialties, computer operators, teachers, dispatchers, controllers, control panel workers).
Group 2 - people engaged in light physical work. CFA - 1.6 (drivers of trams, trolleybuses, conveyor workers, packers, garment workers, workers in the radio-electronic industry, agronomists, nurses, nurses, communications workers, service workers, sellers of manufactured goods).
Group 3 - persons engaged in physical work of moderate severity. CFA - 1.9 (mechanics, adjusters, excavators and bulldozers, bus drivers, surgeons, railway workers, shoemakers, food sellers).
Group 4 - persons engaged in hard physical labor (builders, tunnellers, milkmaids, metallurgists, foundry workers). CFA for men - 2.3, for women - 2.2.
3. There are various methods for determining the daily energy expenditure of a person.
The most accurate method is the method of direct calorimetry, which consists in the direct determination of 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. This method has limitations in relation to various types of activities.
To determine the daily energy consumption for various types activities and everyday life, the method of indirect calorimetry is more often used. With this method, gas exchange is studied. For this purpose, exhaled air is collected in Douglas-Holden bags, the content of carbon dioxide and oxygen is determined in it. The respiratory coefficient (CO 2 / O 2) is calculated: the ratio of carbon dioxide released (l) to the amount of oxygen consumed (l). According to the table, the caloric value of 1 liter of oxygen is determined at a given respiratory coefficient. The amount of oxygen consumed per day and the caloric value of oxygen are multiplied. This will be the daily energy consumption of a person.
Various tabular methods have been proposed:
The main exchange is determined according to the tables of Harris-Benedict. Number A according to weight and sex and number B according to height, age and sex. 2 numbers are added up, which will make up the main exchange. 10% of it is added to this figure (for digestion and assimilation of food). According to the tables of accounting for the work allowance for various types of activities, on the basis of timing, the third component of daily energy consumption is determined, which is added to the value of the basal metabolism and the specifically dynamic effect of food.
For example. It is necessary to determine the daily energy consumption of a tailor 40 years old, weighing 65 kg, height 170 cm, working 8 hours a day, living 4 km from the place of work (30 minutes by bike), for 4 hours, doing housework, sitting rest - 3 hours.
According to the table, the first number A is determined - by weight and gender - 960 kcal. According to the second table, the number B is determined by height, age and sex - 580 kcal. The main exchange will be equal to 960 + 580 = 1540 kcal.
10% is added to this figure, i.e. 154 kcal spent on the specific dynamic action of food.
The work allowance will be:
To work 8 hours x65 = 520 kcal.
For cycling - 1h.x365 = 365 kcal.
For homework 4x80 = 320 kcal.
Sitting rest - 15x3 \u003d 45 kcal.
The tailor's daily energy expenditure will be 1540 + 154 + 520 + 365 + 320 + 45 = 2944 kcal.
The basal metabolism can be determined by the calculation method using formulas that take into account age and gender, or it can be determined from a table taking into account body weight, age and gender, and 10% of the basal metabolism and work allowances are added to it according to tables taking into account the type of activity, rest, homework and time spent on them.
The World Health Organization offers a calculation of daily energy expenditure based on basal metabolic rate and physical activity coefficient. The main exchange is determined by the tables. CFA is calculated as an average for all types of work performed. In this case, all types of activity are taken into account and CFA is taken for each type from the tables, CFA are summed up and its average value is determined. Then the main exchange is multiplied by CFA. This will be the daily energy consumption.
For example. It is necessary to determine the daily energy consumption of a 20-year-old student weighing 70 kg. The student studied at the Department of Surgery (KFA - 2.4), listened to a lecture (KFA - 2.0), worked on a computer (KFA - 1.7), prepared food (KFA - 1.8), ate food (KFA - 1 .5), went to classes (KFA - 1.7), watched TV programs (KFA - 1.5), undressed, dressed (KFA - 1.5), washed (KFA - 1.6).
Average value of CFA = 1.74. The main exchange according to the table is 1750 kcal. The daily energy expenditure of a student is 1750 x 1.74 = 3045 kcal or 12746.4 kJ.
4. In recent years, the time-table method has become widespread. Tables of human energy costs for various activities have been developed, including energy costs for basic metabolism, including sleep.
The timing of the day involves the definition of all types of activities and the time spent on each of them in minutes. In total, there should be 24 hours - 1440 minutes (day). Then energy coefficients are determined in the tables, that is, the energy costs for each type of activity in kcal / min / kg.
Energy consumption is calculated in kcal/kg for each type of activity, taking into account the time spent. To do this, the time in minutes is multiplied by the energy factor kcal/min/kg.
Daily energy expenditures will be the sum of energy expenditures for all types of activities, kcal/kg per day, multiplied by weight, with the addition of 10% of unaccounted for movements.
For example. Determine the daily energy consumption of a student weighing 70 kg.
Timekeeping of a student's day
|
Kind of activity |
Duration, min |
Energy coefficient kcal/kg/min |
Energy consumption, kcal/kg |
|
|
Charging (physical exercise) | ||||
|
Putting on and undressing clothes and shoes | ||||
|
Bed making, personal hygiene |
|
meal | ||||
|
Listening to lectures | ||||
|
Practical classes, seminars | ||||
|
breaks | ||||
|
Riding in transport | ||||
|
Rest sitting | ||||
|
Preparing for classes | ||||
|
Game of chess | ||||
|
36.269 kcal/kg |
||||
To calculate daily energy consumption, 36.27 kcal is multiplied by weight and 10% is added:
36.27x70=2538.9 + 253.89=2792.79 kcal/day (11690.66 kJ/day).
5. The physiological need for nutrients depends on the body's energy expenditure, which reflects age, sex, body weight and labor intensity.
When calculating the daily physiological need of the body for proteins, fats, carbohydrates, it is necessary to take into account daily energy expenditure, a 5-calorie quota of each nutrient, and caloric coefficients.
Calorie quota - the percentage of total calories covered by proteins, fats, carbohydrates. In accordance with the norms of the physiological needs of the population of Ukraine in basic nutrients and energy of November 18, 1999, the caloric quota of proteins is 11%, fats - 25% and carbohydrates - 64%. The amount of energy released during the combustion of 1 g of a nutrient (caloric coefficients) of proteins is 4 kcal, fats are 9 kcal and carbohydrates are 4 kcal.
Protein requirement will be
Daily energy consumption in 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 the performance of a particular work; specific-dynamic action of food. The totality of the components of the daily energy consumption is the working exchange. Muscular work significantly changes the intensity of metabolism. The more intense the work performed, the higher the energy costs. The degree of energy costs for various physical activities is determined by the coefficient of physical activity - the ratio of total energy costs for all activities per day to the value of the basic metabolism. According to this principle, the entire population is divided into 5 groups.
|
Features of the profession |
Physical activity coefficient |
Daily energy consumption, kJ (kcal) |
|
|
Brainwork |
9799 - 10265(2100 - 2450) |
||
|
light physical labor |
10475 - 11732(2500 - 2800) |
||
|
Physical labor of moderate severity |
12360 - 13827(2950 - 3300) |
||
|
Fourth |
hard physical labor |
14246 - 16131(3400 - 3850) |
|
|
Particularly hard physical labor |
16131 - 17598(3850 - 4200) |
For people doing light work sitting, you need 2400-2600 kcal per day, working with a greater muscular load, 3400-3600 kcal is required, performing heavy muscular work - 4000-5000 kcal and more. In trained athletes with short-term intense exercises, the value of the working exchange can be 20 times higher than the main exchange. Oxygen consumption during exercise 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 02 and its consumption is the energy obtained as a result of anaerobic decay, and is called the oxygen debt. Consumption 0 and after the end of muscle work remains high, since at this time there is a return of oxygen debt. Oxygen is spent on the transformation of the main by-product of anaerobic metabolism - lactic acid into pyruvic acid, on the phosphorylation of energy compounds (creatine phosphate) and the restoration of 02 reserves in muscle myoglobin.
Eating enhances energy metabolism (specific dynamic action of food). Protein food increases the metabolic rate by 25 - 30%, and carbohydrates and fats - by 10% or less. During sleep, the metabolic rate is almost 10% lower than the basal metabolic rate. The difference between being awake at rest and sleeping is because the muscles are relaxed during sleep. With hyperfunction of the thyroid gland, the basal metabolic rate increases, and with hypofunction, it decreases. A decrease in basal metabolism occurs when the functions of the sex glands and the pituitary gland are insufficient.
With mental labor, energy consumption is much lower than with physical labor. Even very intensive mental work, if it is not accompanied by movements, causes an increase in energy costs by only 2-3% compared to complete rest. However, if mental activity is accompanied by emotional arousal, energy expenditure can be noticeably greater. Experienced emotional arousal can cause an increase in metabolism by 11-19% over the next few days.
10.1.2. Daily energy consumption
The daily energy consumption of a healthy person consists of: 1) basal metabolism, 2) work increase, i.e. energy costs associated with the performance of a particular work and 3) the specific dynamic action of writing.
Muscular work significantly changes the intensity of metabolism. The more intense the work performed, the higher the energy costs. If the energy costs in the conditions of basal metabolism are on average 1 kcal per 1 kg of body weight per hour, then in a calm sitting position, energy costs are 1.4 kcal/kg/h, in a standing position without tension - 1.5 kcal/kg/h , with light work (clerical workers, teachers, tailors, etc.) - 1.3 - 2.5 kcal / kg / hour, with small muscular work associated with walking (doctors, postmen, etc.) - 2.8 - 3.2 kcal / kg / hour, with heavy physical labor - 5.0 - 7.5 kcal / kg / hour.
The degree of energy costs for various physical activities is determined by the coefficient of physical activity - the ratio of total energy costs for all types of activities per day to the value of basal metabolism (Table 11).
For people doing light work while sitting, 2400 - 2600 kcal per day are required, those working with a muscular load need 3400 - 3600 kcal per day. Muscular work significantly increases energy consumption, so the daily energy consumption exceeds the basal metabolic rate. This increase in energy costs is working increase , which is the greater, the more intense the muscular work. During muscular work, thermal and mechanical energy is released. Attitude mechanical energy to all the energy expended on work, expressed as a percentage is called efficiency (efficiency). With physical labor, the average efficiency is 20%. In untrained people, it is lower than in trained people.
With mental labor, energy consumption is much lower than with physical labor. Intensive mental work causes an increase in energy costs by 2 - 3% compared to complete rest. If mental activity is accompanied by emotional arousal, energy expenditure may be higher (up to 11 - 19%). .
Table 11
Energy consumption for various activities per day
|
Group |
Peculiarities P po profession |
Coefficient physical activity |
|
|
First |
mental food |
2100 - 2450 |
|
|
Second |
light physical labor |
2500 - 2800 |
|
|
Third |
Physical labor of moderate severity |
2950 - 3300 |
|
|
Fourth |
hard physical labor |
3400 - 3850 |
|
|
Fifth |
Particularly hard physical labor |
3850 - 4200 |
Energy needs depend on gender (men have more energy needs), the degree of recreational activity and the level public service, on age (decreases after 40 years) (Table 12).
Table 12
Daily energy expenditure in different age groups
|
Age |
Daily energy expenditure (kcal) |
|
6 months - l year |
|
|
34 years |
1800 |
|
5 - 6 years |
2000 |
|
7 - 10 years |
2400 |
|
11 - 14 years old |
2850 |
|
Boys 14 - 17 years old |
3150 |
|
Girls 13 - 17 years old |
2750 |
Lecture Search
It is customary to divide a person’s energy costs by unregulated: basal metabolism and specific dynamic action of food (food thermogenesis), and adjustable: energy expenditure for mental and physical activities.
BX - this is the amount of energy (energy consumption) necessary to maintain vital processes in humans (cellular metabolism, respiration, blood circulation, digestion, internal and external secretion, nerve conduction, muscle tone etc.) in a state of complete 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).
Approximately the value of the basal metabolism (BMO) for middle-aged (35 years), average height (165 cm) and average body weight (70 kg) is 1 kcal (4.186 kJ) per 1 kg of weight per 1 hour. However modern research showed that the basal metabolic rate is not constant even for a given individual and depends on several factors:
- by gender and age - in men, the SVR is on average 10% higher than in women. BMR is higher in children than in adults; in the elderly, the basal metabolic rate is reduced.
- from height, weight and body composition - an increase in body weight due to body fat leads to a decrease in basal metabolism due to the accumulation of inactive tissue. With an increase in muscle mass, basal metabolism increases.
- from the time of day, season and climate - under the action of low temperatures, the basal metabolism increases, under the action of 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 temperature by 1 ° C leads to increase BOO by 10 - 15 %.. Decrease in hypothyroidism.
The basal metabolic rate can be determined in humans by direct or indirect measurement methods, or by calculation.
— direct measurement (direct calorimetry)- the method consists in the direct determination of 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 released heat is determined by the degree of water heating.
— indirect measurement (indirect calorimetry)- carried out with the help of 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 ºС. At the same time, oxygen consumption, carbon dioxide excretion and, for maximum accuracy of determination, the amount of nitrogen excreted in the urine are evaluated.
— calculation methods- associated with the use of special tables or formulas. The calculation of BOO 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)
Specifically dynamic action of food (SPDA), or nutritional thermogenesis - increase in energy metabolism when eating. This energy is expended 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 fat is metabolized, BOO increases by 4-14%. For carbohydrates, this figure is minimal - 4 - 7%. With a typical mixed diet, the APDP is 10% of the BOO.
Energy expenditure for mental and physical activity (UFD) - refers to regulated energy costs . An increase in energy consumption during the performance of mental and physical work is called work allowance. It is determined according to a special table in kcal / hour for each type of activity,
The sum of the basic exchange, SDDP and the working allowance and is daily energy consumption.
(CFA) is the ratio of total energy expenditure to the body's basal metabolic rate. The higher the energy consumption of the body, the higher the CFA. Total Energy Expenditure (E day) = Basal Metabolism × CFA
Group 1 - persons predominantly mental labor. CFA - 1.4 (scientists, students of humanitarian specialties, computer operators, teachers, dispatchers, controllers, control panel workers).
Group 2 - people engaged in light physical work. CFA - 1.6 (drivers of trams, trolleybuses, conveyor workers, packers, garment workers, workers in the radio-electronic industry, agronomists, nurses, nurses, workers in communications, the service sector, sellers of manufactured goods).
Group 3 - persons engaged in physical work of medium severity. CFA - 1.9 (mechanics, adjusters, excavators and bulldozers, bus drivers, surgeons, railway workers, shoemakers, food sellers).
Group 4 - people engaged in heavy physical labor(builders, sinkers, milkmaids, metallurgists, foundry workers). CFA for men - 2.3, for women - 2.2.
Group 5 - workers engaged in very hard physical labor. CFA is 2.5 These are underground miners, steelworkers, fellers, masons, concrete workers, diggers, loaders, etc.
©2015-2018 poisk-ru.ru
All rights belong to their authors. This site does not claim authorship, but provides free use.
Copyright Violation and Personal Data Violation
Daily energy consumption consists of 3 main positions:1) basic metabolism; 2) specifically dynamic action of nutrients(increase in basal metabolism during the utilization of the diet by 10-15%) and 3) energy costs for the performance of various types of human activities during work and rest.
Daily energy consumption can be estimated by laboratory (direct and indirect calorimetry, etc.), as well as by calculation methods. The most accessible is the calculation method, which allows you to roughly determine the 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 main metabolism.
The calculation technology consists of four stages.
First stage - compiling a detailed timekeeping of human activities for one day (24 hours). Timing should reflect all types of human activities and their duration in minutes for a specified day, including sleep.
Timing example:
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 value of total energy consumption, taking into account body weight.
Let's say body weight this person- 68 kg. The total energy costs will be:
36.18 kcal/kg times 68 kg = 2460.24 kcal.
Fourth stage - calculation of actual (gross) daily energy consumption (kcal/day) taking into account the specific 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 consumption 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, which should be released during utilization in the body: a) proteins; b) fats; c) carbohydrates.
second phase - calculation of the amount of proteins, fats and carbohydrates necessary for the body in grams.
Calculation example:
First stage. Suppose the daily energy consumption of a given person is 2185 kcal. Of them:
- the proportion of proteins should be 14 %
2185 kcal - 100% X \u003d kcal
- fat should be 30% . Compose and solve the proportion:
2185 kcal - 100%
X - 30% X = 
kcal
- the share of carbohydrates should be 56 % . 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 given that burning 1 gram of protein releases 4 kcal, we find the individual need of the body for proteins:
305.9 kcal: 4 = 76.475 g of protein
Knowing the number of calories that should be released when the body utilizes fat, and given that 1 gram of fat releases 9 kcal when burned, we find the individual need of the body for fats:
655.5 kcal: 9 = 72.83 g of fat
Knowing the number of calories that should be released when the body utilizes carbohydrates, and given that when burned, 1 gram of carbohydrates releases 4 kcal, we find the individual need of the body for carbohydrates:
1223.6 kcal: 4 = 305.9 g of carbohydrates
Thus, in order for the body to receive 2185 kcal with a diet, it should include 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 session, the student must:
- make a detailed timing of your working day for the previous day and enter its data into the table;
- draw up a conclusion on the amount of daily energy consumption in accordance with the existing classification of the severity of the work of the population, taking into account age and gender;
PROTOCOL
student's independent work
1. Calculation of the actual (gross) energy costs of the student:
| Activities | Load duration, min | Energy consumption, kcal/min/kg | Total, Kcal/min/kg |
| 1. Sleep | 0,0155 | ||
| 2. Morning work-out | 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. Sitting in a vehicle | 0,0252 | ||
| 11. Riding in transport while standing | 0,0267 | ||
| 12. Lecture notes | 0,0289 | ||
| 13. Practicing standing | 0,0360 | ||
| 14. Practice Sitting | 0,0309 | ||
| 15. Answer at the blackboard | 0,0372 | ||
| 16. Work in the operating room | 0,0316 | ||
| 17. Adult care | 0,0330 | ||
| 18. Caring for a sick child | 0,0310 | ||
| 19. Work on a PC | 0,0289 | ||
20.
Determination of daily energy costsDriving a car |
0,0363 | ||
| 21. Sports (average) | 0,2086 | ||
| 22. Reading to yourself | 0,0209 | ||
| 23. Reading aloud | 0,0250 | ||
| 24. Rest lying down, without sleep | 0,0183 | ||
| 25. Rest sitting | 0,0229 | ||
| 26. Preparing for classes | 0,0309 | ||
| 27. | |||
| 28. |
Total: minutes = kcal =
Body weight (MT) - ______ kg
Total Energy Expenditure (OE) = _________ kcal x (MT) _____kg =________ kcal
An increase in basal metabolic rate (BMS) by 10% is _________ kcal
Gross energy costs are equal to (OE) _________ + (POO) _________ = ____________ kcal / day
2. Calculation of the required amount of proteins, fats and carbohydrates in grams (see the first stage):
proteins ____________________________________ g;
fat ___________________________________________ g;
carbohydrates _______________________________
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 costs?
3. Which of the existing methods for determining the daily energy consumption of a person is most often used in practice?
4. What makes up the daily energy consumption of a person?
5. What is the “specific-dynamic action of food (or nutrients)”?
6. What is the magnitude of the "specific-dynamic action of food"?
7. What is a “basal exchange”?
8. What is the average value of the “basal metabolism” for a woman, for a man?
9. What factors influence the size of the “basal metabolism”?
10. How does the age of a person affect the value of “basal metabolism”?
11. How does the gender of a person affect the value of “basal metabolism”?
12. How is the ambient temperature reflected in the value of “basic metabolism”?
13. How does the state of human health affect the value of “basal metabolism”?
14. What hormones increase the value of "basal metabolism"?
15. What hormones lower the value of "basal metabolism"?
16. In what units is the value of “basic metabolism” estimated?
17. What do you understand by the term “unregulated” energy costs?
18. What do you understand by the term “regulated” energy costs?
19. How does a person's energy needs affect his activity?
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 one gram of protein is utilized by the body?
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 intake?
26. What percentage of a person's daily energy expenditure should be offset by fat consumption?
27. What percentage of a person's daily energy expenditure should be offset by carbohydrate intake?
28. In what units is the energy value of proteins, fats, carbohydrates estimated?
29. How, knowing the daily energy consumption of a person, can one calculate the required amount of proteins, fats, carbohydrates to compensate for these energy costs?
30. What groups is the population divided into in the existing classification of labor according to the degree of its severity?
31. What principles are incorporated in the existing classification of the population according to the severity of labor?
32. Representatives of what professions make up the first group in the classification of the population according to the severity of labor?
33. Representatives of what professions make up the second group in the classification of the population according to the severity of labor?
34. Representatives of what professions make up the third group in the classification of the population according to the severity of labor?
35. Representatives of what professions make up the fourth group in the classification of the population according to the severity of labor?
36. Representatives of what professions make up the fifth group in the classification of the population according to the severity of labor?
37. What age groups is the adult able-bodied population divided in the classification of labor according to the degree of its severity, depending on gender?
38. What are the energy costs of male and female students?
Methods for determining the energy consumption of the body
The processes of energy exchange are based on the laws of thermodynamics, i.e. the laws of mutual transformations of various types of energy during its transitions 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, to determine the energy production in the body, calorimetry methods (direct and indirect), as well as the study of gross metabolism, are used.
Direct calorimetry.
This method is based on the direct and complete recording of the amount of heat released by the body in biocalorimeters (sealed and well insulated from external environment a chamber in which water circulates through tubes, oxygen is supplied and excess carbon dioxide and water vapor are absorbed).
Depending on the degree of heating of water and its mass, an assessment is made of the amount of heat released by the body per unit time.
Indirect calorimetry.
Unlike direct calorimetry, indirect calorimetry methods are more convenient and simple. This technique includes two methods for assessing the energy consumption of the body:
1. Incomplete gas analysis.
2. Complete gas analysis.
Incomplete gas analysis is based on determining the amount of oxygen consumed by the body, followed by the calculation of heat production.
For this purpose, spirometabolograph devices are used. , representing a closed system, which consists of a spirometer and a carbon dioxide absorber. In accordance with the rhythm of breathing, a spirogram is recorded . The slope of the curve corresponds to the amount of absorbed oxygen.
Knowing the volume of oxygen absorbed in 1 min, the average respiratory coefficient and the corresponding caloric equivalent of oxygen, one can calculate the 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 the calculation of heat production.
Closed and open systems are used to assess the intensity of gas exchange in a complete gas analysis.
In devices of closed systems, it is provided for the subjects to inhale air or oxygen from a closed space, the exhaled air is directed into the same space.
The most common is an open method for studying heat production - the Douglas-Haldane method. The advantage of this method is the fact that the body's energy consumption can be determined during the performance of any work. The essence of this method lies in the fact that within 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 taken into the mouth or a rubber mask worn over 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 filled, the volume of exhaled air is measured, in which the amount of oxygen and carbon dioxide is determined.
Scheme for determining energy costs by the Douglas-Haldane method.
1. At the first stage, after performing certain work, the quantities of consumed O2 and emitted 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 decreased and the carbon dioxide content in the exhaled air increased.
2. Based on the data obtained, the calculation of the respiratory coefficient is carried out. Respiratory coefficient is the ratio of the volume of emitted CO2 to the volume of absorbed O2.
DC = CO2 (l) / O2 (l)
The respiratory coefficient (RC) is different for the oxidation of proteins, fats and carbohydrates.
For example, when glucose is oxidized, the number of CO2 molecules formed and the number of O2 molecules absorbed are equal, so the DC for carbohydrates is 1.
With the oxidation of fats and proteins, DC will be below unity. So, during the oxidation of fats, it is 0.7, and proteins 0.8.
With mixed food, DC is 0.8-0.9.
In starvation 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). CEC 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 CEC is multiplied by the amount of oxygen consumed and the amount of energy necessary to perform a certain type of activity is found.
Respiratory coefficient during muscular work.
Carbohydrates are the main source of energy during intensive muscular work.
Therefore, during operation, the DC approaches unity. Immediately after the end of the work, it can rise 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 emitted is higher than usual for a short time. Enhanced ventilation of the lungs in these cases prevents the shift in the pH of the blood and tissues to the acid side.
Some time after the completion of the work, the DC may drop sharply compared to the norm. This is due to a decrease in the release of CO2 by the lungs due to compensatory retention by its buffering blood systems, which prevent a shift in pH to the main side.
Approximately an hour after the completion of the work, the DC becomes normal.
BX
BX- the minimum amount of energy necessary to ensure normal life in conditions of relative physical and mental rest. This energy is spent on the processes of cellular metabolism, blood circulation, respiration, excretion, maintaining a constant body temperature, functioning of the vital nerve centers of the brain, constant secretion of the endocrine glands, maintaining muscle tone.
Energy consumption at rest various fabrics organisms are not the same. So, the liver consumes 27% of the energy of the main metabolism, the brain - 19%, muscles - 18%, kidneys - 10%, heart - 7%, all other organs and tissues - 19%. Internal organs consume energy more actively than muscle tissue. The intensity of basal metabolism in adipose tissue is 3 times lower than in the rest of the cell mass of the body.
The dependence of the intensity of basal metabolism on body surface area was shown by the German physiologist Rubner for various animals – Rubner's body surface law. According to this rule, the intensity of basal metabolism is closely related to the size of the body surface: in warm-blooded organisms that have different sizes body, the same amount of heat is dissipated from 1 m2 of surface.
Any work - physical or mental, as well as eating, fluctuations in ambient temperature and other external and internal factors, changing the level of metabolic processes, entail an increase in energy consumption.
Therefore, the main exchange is determined in strictly controlled, artificially created conditions. To determine the main exchange, the subject must be:
1. In a state of physical and psychological rest, i.e. in a prone 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 a meal. The increase in metabolic rate after eating begins after 1-2 hours and can last for 12 hours, and after protein intake this period can reach 18 hours.
3. At a "comfort" 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 must also be taken into account when determining the basal metabolism.
Factors that determine the amount of basal metabolism.
The basal exchange 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 features of the physique (height, body weight);
3. Sex. 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.
Seasonal fluctuations in the basal metabolic rate (its increase in spring and decrease in winter) were noted.
Methods for determining the main exchange.
The basal metabolic rate can be calculated using the Dreyer formula, according to which, the daily basal metabolic rate in kilocalories (H) is:
, Where:
W - body weight in grams,
A is the age of the person
K is a constant equal to 0.1015 for men and 0.1129 for women.
It is also possible to evaluate basal metabolic rates using special tables that allow you to determine the average level of a person's basal metabolism by height, age and body weight.
Formulas and tables of basal metabolism represent average data derived from a large number of studies of healthy people of different sex, age, body weight and height, therefore, there are methods that allow you to calculate the deviation of basal metabolism 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
Work metabolism is a combination of the basic metabolism and energy costs of the body, ensuring its vital activity under conditions of thermoregulatory, emotional, nutritional and workloads.
A thermoregulatory increase in the intensity of metabolism and energy develops under cooling conditions and in humans can reach 300%.
During emotions, an increase in energy expenditure in an adult is usually 40-90% of the level of basal metabolism and is associated mainly with the involvement of muscle reactions. Listening to radio broadcasts that evoke emotional reactions can increase energy expenditure by 50%; in children, screaming can triple the energy expenditure.
The working exchange exceeds the main exchange, mainly due to the functions of the skeletal muscles. With their intensive contraction, the energy consumption in the muscle can increase 100 times, the total energy consumption with the participation of more than 1/3 of the skeletal muscles in such a reaction can increase 50 times in a few seconds. In the population of industrialized countries, daily physical activity is relatively small, so the 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 prone position. A standing person spends 40% more energy than in the conditions of basic metabolism. 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, it is possible to significantly increase the reserves of human health 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 that increase catabolism.
Physical activity coefficient– the ratio of total energy consumption for all types of life activity to the value of the basal metabolism, i.e. energy consumption at rest, This indicator is an objective physical criterion that determines the adequate amount of energy expenditure for specific occupational groups of people. The values of the coefficient of physical activity are the same for men and women, but due to the lower body weight in women and, accordingly, the basal metabolism, the energy consumption of men and women in groups with the same coefficient of physical activity is different.
Group I. Very light physical activity.
Daily energy expenditure of the body
Physical activity coefficient 1.4. Energy consumption 1800-2450 kcal/day. This group includes predominantly mental workers (scientific workers, students of humanitarian specialties, computer operators, dispatchers, control panel workers, etc.).
Group II. Light physical activity. Physical activity coefficient 1.6. Energy consumption 2100-2800 kcal/day (workers engaged in light physical labor: drivers of trams, trolleybuses, conveyor workers, weighers, service workers, nurses, nurses, etc.).
Group III. Average physical activity. Physical activity coefficient 1.9. Energy consumption 2500-3300 kcal/day. This group includes workers of moderate labor (locksmiths, drillers, bus drivers, surgeons, textile workers, railway workers, blast-furnace metallurgists, workers of chemical plants, etc.).
Group IV. High physical activity. Physical activity coefficient 2.2. Energy consumption 2850-3850 kcal/day. (workers of heavy physical labor: construction workers, assistant drillers, sinkers, 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 3750-4200 kcal/day. This group includes workers of especially hard work, only men (agricultural workers during the sowing and harvesting periods, miners, fellers, concrete workers, masons, diggers, loaders of non-mechanized labor, etc.).
For each group of labor, the average values of the balanced need of a healthy person for energy and nutrients were determined.
Didn't find what you were looking for? Use the Google search on the site:
5. Energy exchange
Direct and indirect calorimetry
Metabolism of matter and energy is essentially a single process. As a result of complex transformations occurring in the body, heat is generated.
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 methods.
direct calorimetry produced using special apparatus - calorimetric chambers (Fig. 59).
The chamber walls do not conduct heat. A system of tubes with water 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. Measure the temperature of the water entering and leaving the chamber; determine the temperature difference and the amount of water flowing. 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 of various activities
But this method is very complicated, cumbersome, and, most importantly, it does not make it possible to measure the energy expenditure of the body during various types of human activity (cycling, working at a blast furnace, etc.).
It is easier to calculate energy consumption by the method indirect calorimetry.
Rice. 59. Scheme of the calorimeter. 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 watch (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 are going on in it. Consequently, the more the body consumes oxygen and emits carbon dioxide. Therefore, the energy processes in the body can be judged not only by the amount of heat given off to the environment, as is done with direct calorimetry, but also by the amount of oxygen absorbed and carbon dioxide released, i.e., by the magnitude of gas exchange.
To determine the amount of oxygen taken in and carbon dioxide released, various devices are used. In production and educational conditions, masks are used for this purpose.
The mask is connected through a valve system to a bag made of airtight fabric (Fig. 60), which is fixed on the subject's body. 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 watch to determine its volume, and then the percentage of oxygen and carbon dioxide in it is determined chemically. Knowing the composition of the inhaled and exhaled air, it is possible to calculate the amount of oxygen absorbed and exhaled carbon dioxide.
The oxygen absorbed by the body is used to oxidize proteins, fats and carbohydrates. For the oxidation of 1 g of proteins, fats or carbohydrates, a different amount of oxygen is required, and therefore, a different amount of energy is also released (Table 14).
Table 14. Energy generation during the oxidation of substances in the body
Table 14 shows 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 - are oxidized in the body. To do this, determine the value of the respiratory coefficient.
The respiratory coefficient is the ratio of the volume of carbon dioxide released by the body to the volume of oxygen absorbed. The respiratory coefficient is different for the oxidation of proteins, fats and carbohydrates. The oxidation of carbohydrates (glucose, for example) can be expressed by the equation:
It can be seen from the equation that during the oxidation of glucose, the number of molecules of carbon dioxide formed and absorbed oxygen is equal. Therefore, the respiratory coefficient during the oxidation of carbohydrates is equal to one:
There is little intramolecular oxygen in the fat molecule, so more oxygen is required for its oxidation. The respiratory coefficient in this case is less than 1. When proteins are oxidized, the respiratory coefficient is 0.8. With the mixed food that a person usually consumes, the respiratory coefficient ranges from 0.85 to 0.9.
When proteins, fats and carbohydrates are oxidized (when 1 liter of oxygen is consumed), different amounts of energy are released. Consequently, with a different respiratory coefficient, the amount of liberating energy when 1 liter of oxygen is absorbed will be different. This dependence is visible from Table 15.
Knowing the amount of gas exchange, you can calculate the energy consumption in the body. They act like this.
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, according to 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. Thus, the amount of energy given by a person for 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 released carbon dioxide) per unit time.
BX
Even in conditions of complete rest, a person consumes a certain amount of energy. In the body, energy is continuously spent on physiological processes that do not stop for a minute. There are metabolic processes in the cells, a constant body temperature is maintained.
The minimum level of metabolism and energy expenditure for the body is called main exchange.
The main metabolism is determined in a person in a state of muscle 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 mass per hour. On average, this is 7,140,000-7,560,000 J per day.
For each individual, 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. With insufficiency of the function of the thyroid gland, pituitary gland, gonads, the basal metabolism decreases.
Energy expenditure during muscle activity
The harder the muscular work, the more energy a person spends. For schoolchildren, preparation for a lesson, a lesson at school require energy 20-50% higher than the energy of the main metabolism.
During laboratory work, manual labor, simple gymnastics, games of average mobility, energy costs are 75-125% higher than the basal metabolic rate.
When walking, energy costs are 150-170% higher than the energy of the main metabolism. When running, climbing stairs, energy costs are three to four times higher than the main metabolism.
Boys usually have higher energy expenditure than girls. Training the body significantly reduces the energy consumption for the work performed. This is due to a decrease in the number of muscles involved in the work, as well as changes in breathing and blood circulation.
With the mechanization of labor in agriculture and industry, the introduction of machine technology, the energy costs of working people are reduced. With mental labor, energy costs are lower than with physical labor.
People of different professions have different energy expenditures.
Energy consumption in the body can be divided into 2 groups: basic metabolism and additional metabolism. How to calculate them and determine the energy consumption of a person?
The most accurate way to determine the body's energy consumption is through clinical diagnostics. Currently, to determine energy expenditure, in most cases, the method of indirect calorimetry is used to assess basal metabolism and load-respiratory calorimetry to obtain information on energy expenditure at different levels of physical activity. Modern metabolic analyzers allow you to determine the energy consumption of the body with a minimum error. Also, an individual study of the gastrointestinal tract is usually carried out, on the basis of which it is possible to more accurately determine the specific dynamic effect of food and give the necessary recommendations in nutrition. There are a number of other studies that allow you to accurately determine the body's daily need for energy and macronutrients (proteins, fats and carbohydrates), and, accordingly, most accurately select an individual diet and draw up an optimal exercise program. We strongly recommend that you consult a professional dietitian and undergo all the necessary examinations to create an optimal weight management program.
For those who don't like doctors.
Based on numerous definitions of basal metabolism in humans, tables of averaged normal values of this indicator have been compiled depending on age, sex and total body surface.
There are also many formulas and methods for determining the average basal metabolic rate (according to Dubois, according to Dreyer, according to Harris-Benedict). IN Lately The Mifflin St Jeor technique gained popularity. There is also the Katch-McArdle formula (Katch-McArdle), which calculates the basal metabolic rate on a fat-free body mass. Accordingly, in order to use it, you need to know the percentage of fat in your body. Whatever method or formula you use, the data obtained will not differ much from the average.
In addition, there is such a thing as the specific dynamic action of food (SDA) - the energy costs of the body associated with the consumption and digestion of food. The average figure for SDD is 10% of the main exchange.
After calculating the main exchange, it is necessary to determine the additional exchange. There is an average classification of additional exchange values depending on professional activity or physical activity, which is called the coefficient of physical activity.
For example, the formulas for calculating the basic metabolic rate according to the Mifflin-San Geor 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
Having calculated the average statistical value of the main exchange, it is possible to calculate the value of the additional exchange. To do this, we multiply the resulting number by the coefficient of physical activity.
Physical activity coefficients:
- Minimum loads (knowledge workers, sedentary work) = 0.2
- Some daily activity or light exercise 1-3 times per week = 0.375
- Moderate work or training 4-5 times a week = 0.4625
- Intense training 4-5 times a week = 0.550
- Daily workouts = 0.6375
- Daily intensive training or training 2 times a day = 0.725
- Hard physical work or intense training 2 times a day = 0.9
For example, let's calculate the energy consumption for a female leader, whose age is 35 years, height - 166 cm and weight 65 kg.
Basic exchange \u003d (10 x 65) + (6.25 x 166) - (5 x 35) - 161 \u003d 1351.5
Specific dynamic action 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 rate 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 content of the diet, for which it is absolutely impossible to fall, can be calculated by the formula:
Weight (in grams)/450*8
65000 / 450 x 8 = 1155.5
Organizing meals to constantly keep a given calorie limit is quite difficult, so if you yourself calculate and prepare your diet, determine the calorie corridor.
Calories for weight loss - 200 = lower limit of the range
Calories for weight loss + 100 = upper limit of the range
For comfortable weight loss and avoiding breakdowns, it is not recommended to reduce the calorie 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 the method of clinical diagnostics - load-respiratory calorimetry, which can be used to obtain information about individual energy consumption at different levels of physical activity.
On the basis of many observations and measurements, the average statistical values of energy consumption for various physical activities were determined.
Methods for determining daily energy costs
You can find a table with these values here (link).
Multiply your basal exchange rate by the average rate from the table, divide by 24 (hours per day) and multiply by the time spent on the selected activity.
For example:
The basic exchange of a woman at a rate above 1351.5. 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 way overload the cardiovascular and nervous system, muscles, bones and ligaments. If you yourself want to determine the optimal load, then 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 classes gradually, giving the body the opportunity to get used to a new way of life. A sharp increase in loads can harm an unprepared body and is likely to cause hostility on a psychological level. We also recommend that you monitor your heart rate or, scientifically, your heart rate (HR) without fail. Constant monitoring of heart rate will not only prevent overwork and injuries, but will also allow you not to spend hours on half-hearted workouts.
You can determine the optimal heart rate for your body with the help of clinical diagnostics of the cardiovascular system. We also strongly recommend that you consult with a professional fitness trainer to draw up 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 bound |
| 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 make a balanced nutrition plan.
