Energy

0:04 [music] Welcome to the week six section on uh energy, carbohydrate, protein and fat. This is going to be the macro uh nutrients and the prime nutrients for a human body. At the end of this session, uh student will be able to identify the occurrence in the body composition, the classification of energy, the functions of energy, the energy requirements, uh metabolism and measurement of the energy. So, uh when we talk about energy per se, uh human body is like an engine

0:51 which needs energy or fuel to keep the vital functions going on the top gear. Just imagine a car without a fuel. It cannot run or it cannot do its work. Similarly, our body uh fuel of our body functioning and our body's uh engine has to be activated only by giving energy to the human body. The energy comes via uh consumption of food and uh other nutrients also water. So these things are considered to be the major energy source. When it comes to water, water does not provide much of calories or nil calorie as such. Whereas other food items will give kind of energy to our

1:38 body. Energy is measured by calories. That's a common term that will be used when we talk about energy. Calories are widely used for various purposes. So when we talk about uh calorie counts um [snorts] the calorie is uh basically nothing but measured as a jewel also. So I will be discussing about that in the later part of the slides. Similarly the body requires energy for metabolic purposes, growth, maintaining the body temperature, physical activity and all that. So we basically require energy for all these purposes to have a healthy life. So how do we measure energy?

2:23 Energy is measured by 1 kilo calorie is nothing but 1,000 calories. Similarly 1 calorie is nothing but 0.001 kiloalorie and calorie and jewel are simultaneously used as a unit of energy. 1 kilojoule is equal to nothing but energy expended one when 1 kg is moved through 1 meter by a force of 1 newton. So 1,000 jw is equal to 1 kiloj. This is the measurement of energy when we talk about the energy calculations. So 1,000 kiloj is equal to 1 mega joule which is mg. Therefore 1 kiloj is equal to 0.24 kilo calories. So

3:09 that is what you should remember as 1 calorie is 0.007 kiloalorie and 1 kiloalorie is nothing but 0,000 calories. When we understand the term energy, calories and all that these things are always linked with the body weight and how the calories have to be consumed. All these things are dependent on BMI which is nothing but body mass index. Body mass index is nothing but a weight stature index which can be used both as a measure of obesity as well as protein energy malnutrition. This particular term is very commonly used and people can easily follow this particular formula of BMI which is body mass index is nothing but using weight

3:55 and height you can measure the BMI. Weight in kgs divided by height in me squared will give you the BMI of a particular person. If your BMI is falling under uh these categories, you are termed as a respective um under the calculation of WH standards. So if the BMI is less than 18.5 kg per meter squared, you are termed as underweight. And a normal person's BMI should be 18.5 to 24.9 kg per meter squared. Whereas an overweight person will have a BMI ranging between 25 to 29.9 kg per meter squared. Similarly, obese grade 1 and grade 2 are the other classifications which are given as 30 to 34.9 kg per

4:43 meter squared and grade 2 will be 35 to 39.9 kg per meter squared and above 40 kg per meter squared the person is termed as morbidly obese or grade three category. So if you can see how the body built is and how the body's uh weight and height is being distributed with regard to the different classifications. Coming to the occurrence. So when I talk about energy, energy is not stored in a single form. It exist across multiple storage systems. The primary stores are nothing but glycogen in the liver, adipos tissue, muscle proteins and ATP. So these four are the major occurrence. So starting with glycogen, glycogen is a

5:28 major source of energy which is primarily stored in the liver up to up to 100 g sorry up to 100 g and in skeletal muscle it is stored up to 400 g. So the body can store a maximum of about 500 g of glycogen producing about 2,000 calories approximately 1 days worth of energy. So that's it with uh glycogen storage. If you see the glycogen structure here, that's how it is stored in the liver and that's a major source of energy and that's a first form of energy as well. Adipost tissue is another uh way where fat is getting deposited. Fat is a far more important storage form than glycogen

6:15 because the oxidation of 1 gram of fat releases about twice as much of energy as the oxidation of 1 g of glycogen. So that means fat oxidation releases more energy compared to the glycogen. That means 1 g of fat gives about 9 cal whereas 1 g of carbohydrate gives only four cal. So it is the double the quantity of the glycogen or the carbohydrate. An average adult stores enough fat to last for nearly a month with most of it is stored in adipos tissue and they are released into the bloodstream as needed. I will give a small example as a fasting. If somebody is fasting for 24 hours and is not taking any food at all,

7:02 first thing the body releases is the liver glycogen which can stay up to 24 hours. So first the liver glycogen is converted to glucose and it releases energy. So the body's activity takes place. The next day also the person is fasting. Then comes the fat. fat will be released from the body from the various uh adipos tissues and that will be converted to uh energy and that will be used up for the various activities of the human body. >> [snorts] >> So that's what is said is an average adult stores enough fat to last about nearly a month with respective uh stoages in adipost tissue and all that

7:48 and then it is released in the bloodstream as and when it is needed that's for the adipos tissue. So we have a white adipos tissue and a brown adipos tissue. So you can see how it is distributed also. Next we move on to the muscle protein. So first is the glycogen which is a carbohydrate which is getting uh used up [snorts] for energy. Next is the fat that is used up for the energy. Once the fat is also completely depleted only the person will go for the protein breakdown. Protein's main role is to use use up for building the muscles and building the tissues repairing and maintenance. This is its major work. Whereas protein uh carbohydrate and fat

8:34 will release energy. That's their major function. If both are not present, next work of the protein is to give energy rather than helping in the building up of cells or tissues. So its work is being compensated and it will start producing energy to the body. When the muscle glycogen stores completely fall in the later stages of endurance activities or any other activities, the body will break down the amino acid found in the skeletal muscle protein into glucose supplying about [snorts] 15%age of the energy that is required to the body. Protein is also used when the daily diet is inadequate in total calories or carbohydrates. That is what I said. So once the liver glycogen is

9:19 depleted and the fat from the adipos tissue is also depleted the last resort is going to be the protein depletion from the skeletal muscle. So that is going to be broken down to glucose and that will be releasing the energy required for our bodily activities. That's how the muscle protein gets broken down. And next we move on to the adinosine triphosphate which is nothing but the ATP. ATP is commonly referred to as the energy currency of the cell. It provides readily releasable energy in the bond between the second and the third phosphate groups. So if you see that is the major uh energy that you can observe. The ATP is the uh one which is going to release the energy in the second and the third phosphate group. It

10:06 is consumed for energy in processes including ion transport, muscle contraction, nerve impulse propagation, substrate phosphorilation and chemical synthesis. So these are the things why the energy is required for our body and how it can be utilized in the body. So if you see ATP this is how it is and uh uh we have looked into the various uh sources of uh energy. We move on to the other classification of uh energy which is the alcohol is also something that will yield energy to our body and which is going to be only calories and not other nutrients also. Whereas uh metabolic form is nothing but the

10:52 kinetic energy, chemical energy, thermal energy are also going to produce some form of energy to us. So the first is the foremost energy producer is the carbohydrate. If you see carbohydrate is the major source of energy only central nervous system and uh brain and all that will include only this major source as a uh source of energy for them to carry on with their activities. Similarly, even red blood red blood cells will rely solely in carbohydrates for the energy. And next we move on to the fat which is nothing but the fat from the adipos tissue. The main function of lipids is to provide or store energy. The last resort is going to be the protein where protein can also provide energy though it is this is uh a

11:40 relatively minor function of the protein because these two are the major energy sources. only when they fail we move on to the protein for the energy purposes. Whereas alcohol will also eat yield some kind of energy 7 kilo calalorie per gram of alcohol and is metabolized in the liver if you see and but it provides no nutritional value beyond calories. So that means only calories it provides no other nutrient that you can expect from the uh alcohol that you are uh consuming. Similarly, kinetic energy is energy of movement that is a muscle contraction. Chemical energy is stored in molecular bonds. Example, the ATP, glycogen and fat which I discussed in the previous slide also. Whereas thermal energy is nothing but heat produced during the metabolic reactions.

12:28 Coming to the total energy metabolism, you can see that uh total energy metabolism is nothing but that it's a measure that you're going to make for the total amount of energy throughout 24 hours even if a person is sleeping or functioning. This also includes the basal metabolic rate which is the BMR plus the additional energy required for the activity during waking hour. So this is the major energy metabolism that you should know. The relationship of BMR and the total energy metabolism in an averageely moderate active man is approximately 1 is to2. So if you see the energy metabolism is a combination of energy balance that is the energy

13:15 consumption and the energy expenditure. So it has to be on the balance. If one is more then there will be a issue in the underweight and the overweight uh possibility. So that is is uh regarding the energy total energy metabolism. So we have different factors affecting the total energy uh metabolism. So if you see the muscular activity is uh nothing but the estimated energy utilized under different conditions of muscular activity uh is given in the tableau column. If you see sleeping gives about uh 65 calories per hour for an average 70 kg man. This is given. [snorts] If you're awake but lying still 77 calories.

14:01 Sitting or standing relaxed 105. Dressing and undressing 118. Sweeping gives about uh utilized energy utilizes about 169. Walking 4 kilometer per hour about 200 cals and bicycling about 245 whereas walking 6 kilometer per hour you can uh you know expect energy of about 300 kilo calories. You can expend that. [snorts] Walking downstairs uh 374 swimming is very uh good in uh expending energy about 500 calories per hour you can uh expend that way. walking upstairs and all that is given in the tableau column.

14:46 So you can see how we determine the energy requirement for a person. The component of total energy requirement is nothing but the energy expenditure forms an important part in estimating the energy requirements. There are three components of energy expenditure. If you see first is the basal metabolic rate. So when we move on to the basal metabolic rate, basal metabolic rate is nothing but the amount of energy required to carry on the involuntary work of the body. So you can see the heart is beating which is nothing but the involuntary activity and the functioning of these organs like liver brain and lungs. It includes the various functional activities of these organs.

15:33 It refers to the minimum energy requirement for a healthy adult to maintain the life. There are different factors that are contributing to the BMR which is nothing but uh basal metabolic rate. If you see sleep is the first uh you can see the different composition here uh factors here. Body composition. So when it comes to body composition, muscle, brain and liver consume large amounts of oxygen per unit weight energy requirement. So if a person's body composition is high, the BMR is going to be more. Similarly, body condition. The weight of a less active person represents less muscle and

16:20 more fat. Therefore, the basal energy needs are lower. Diff uh gender differences are also there. If there is a there is a difference in the body composition also between men and women of the same age and height and weight are also being documented. Women will have more adipose tissue. Uh this is reflected in the low BMR in women similarly whereas [snorts] uh men will have a higher BMR. Next is the sleep. So during sleep both muscular and emotional relaxation is more great which causes a drop in the energy needs. Similarly when we talk about age at birth there will be more uh BMR up to 2 years the BMR keeps

17:08 increasing until puberty there is a gradual decrease whereas in 35 to 45 years the decline is 45 kilo calories per day. >> [snorts] >> Similarly during pregnancy also in the sixth to 7th month the BMR increases to 20%age above normal due to the high metabolic activity of the fetus placenta and maternal tissues. Similarly for undernourished person the cal because of the calorie restriction the BMR uh is reduced to 20%age and uh for a person who smoking the nicotin present in the uh cigarettes will increase the BMR by approximately 10 percentage. So these are some of the factors that you should remember when we talk about

17:54 body composition, body condition and also sleep uh whether you are undernourished or overnourished and during pregnancy with different age groups all that the BMR keeps varying. Next we move on to the thermic effect of foods. That's a second component in the uh difference in the energy metabolism. So if you see there are food items that we consume and that will also produce some kind of heat or energy uh in excess of the basal metabolism caused by the ingestion of these nutrients. So if you see when you consume a protein richch food it it uh the thermic effect is about 12%age whereas if you consume carbohydrate it is about 6% and for fat

18:41 it is 2% and for the mixed diet it is about 10 percentage. So if it's a combination of all protein, carbohydrate and fat and also the other nutrients. So the mixer diet is going to be about 10%age. The third component is nothing but the physical activity. Always remember energy goes in hand to hand with the physical activity. If you're physically active, just imagine if you're doing some light work like painting, driving, domestic work, it is considered to be light work. It about 150 to 24 294 kiloalorie per hour is being expended. Some activities are essential for the Hindu and the community and can be considered as

19:28 economic activities which are life sustaining. Moderate activity is nothing but playing a tennis uh doing cycling doing some agricultural work. So you spend about 300 to 444 kilo calorie per hour whereas heavy work we consider to be in in the form of coal mining and activities like football, hockey and all that. So you expend about 450 to 594 kilo calorie per hour. So when we talk about energy uh requirements, we have discussed about the BMR, the physical activity and the thermic effect of food. How do we understand the energy output? How can we determine? So there are two different

20:13 ways by which you can identify the uh energy output. One is direct calorimetry and the other one is indirect calorimetry. >> [snorts] >> When we talk about direct calorimetry, uh this is being uh referred to as uh Atwater Rosa Benedict's uh apparatus where if you see a person uh a subject lives inside the apparatus for a specific amount of time and uh the heat will be produced no that is measured by the circulating water through a copper tube inside a constant chamber. So if the energy measurement is made from actual heat produced this is referred to as direct calorimetry. So this is being identified by Atwater Rosa

20:59 and Benedict. So that's why it is called as Atwater Rosa Benedict apparatus. So this again if you see it's a water cooled insulated chamber with a device for supplying oxygen and removing the carbon dioxide. So this is the actual apparatus that you are able to see. The thermouples placed inside the chamber will measure the changes of the temperature of water which is circulating through it. That is how it is being calculated. The water vapor and the carbon dioxide are absorbed by sulfuric acid tower and soda lime respectively.

21:46 So when when I talk about the advantages it is about 99% accurate because it's being uh given in the direct calorimetry form. So it gives about 99% accurate. The disadvantage here is it involves the use of expensive equipment. this particular equipment uh which is nothing but that water rosa benetic apparatus we need to buy this instrument and some person has to go inside and that has to be done in the form of this uh procedure and that's the major disadvantage that I would say here and it's not suitable for critically ill patients whose uh calorimetry or whose energy output is very much needed for us

22:33 so that cannot be done with regard to the direct calerimetry. Hence, we move on to the indirect calorimetry where the principle here is uh you measure the gaseous exchanges that takes place with regard to oxygen consumption and carbon dioxide output measuring the thermal equivalent of the gases. The heat produced is based on the calculation of the thermal equivalent [snorts] of carbon dioxide is variable. Hence it is preferred to rely on the oxygen consumption only. So if you see the nature of the food being uh combusted and the time of experiment can be measured by noting the respiratory quotient of the subjects which is

23:19 nothing but the RQ respiratory [snorts] quotient. The indirect method measures the metabolic rate by determining with a spyometer that is the oxygen consumption and carbon dioxide production of the body over a given period of time. Rq is is nothing but the moles of carbon dioxide expired divided by the moles of oxygen consumed. So this is the major uh step that you are observing here in the indirect calorimetry. So if you see the principle is basically on the measuring the gaseous exchange between the oxygen consumption and the carbon dioxide output. [snorts]

24:04 So when I talk about the RQ or respiratory quotient uh for carbohydrate rich food which is is 1 whereas fat it is 7 and for protein is 0.82. 82 and if it's a mixer diet it is 0.85 this indicates that the d the conversion into kilo calories of the heat produced per square meter of the body surface or hover and is extrapolated to energy expenditure in 24 hours. This RQ depends on the fuel mixture being metabolized. The major advantage here is it has the advantage of mobility. So you can take it wherever you want to and the equipment is uh low in cost compared to

24:50 the direct calerometry where it is fixed and a person has to come there inside and then the process takes place and uh it can be applied even when the person is at rest or engaged in various activity. So that's the disadvantage that I could say with regard to the indirect calorie me meter. So apart from this even food that we consume can be measured in terms of energy and for this we need a specialized uh equipment called bomb calorie meter. Bomb calorimeter has been used to determine the calorie thick value of foods. So if you see uh we uh we have been discussing about the calories from different types of food and all that. How do we measure that? We

25:36 measure that using the bomb calorie which is used to determine the calorific value of foods. So all these uh experiments have been done uh ages since ages and we have come up with variety of uh [snorts] uh discoveries and we have come up with a lot of uh calorific value with regard to the food based on these kind of uh measurements using bomb calorimeter and all that. ICMR, Indian Council of Medical Research and uh National Institute of Nutrition has been uh doing a lot of research work and it has come up with lot of uh uh energy uh values, calorific values for different varieties of foods. So the major concept or the major principle behind this is

26:21 heat is generated by direct burning of the food. Thereby energy is calculated by measuring the oxygen that is used to burn the desired quantity of food. So if you see carbohydrate gives 4 kilo calorie per gram of edible portion whereas fat gives 9 kilo calorie per gram of edible portion. Similarly with protein 4 kilo calorie per gram of edible portion. So if you see carbohydrate and protein share the same calorie whereas fat is little more higher and it shares about 9 kiloalorie per gram of the edible portion. >> [snorts] >> This indicates that when the heat is generated on burning of the food which is kept in the burn calorie meter that is calculated or measured by the oxygen

27:09 which is needed to burn the amount of food that is present inside the bomb calorometer. Since the heat is generated that has to be measured in terms of calories. As I said, energy is termed in the calorie termed as calories. So this is the structure of the bomb calorie meter. As you can see in the picture, it consists of a heavy steel bomb with a platinum or a goldplated copper lining with a cover that is tightly in place by means of a string screw collar. So this is a heavy steel bomb with a platinum and a goldplated or a goldplated copper lining with a cover that is held tightly

27:55 in place by means of a strong screw collar. If you keep the var amount of sample here either it should be pressed in the form of a pellet or placed inside within the capsule inside the bomb. [snorts] This is then closed and charged with oxygen under a pressure of 300 lb per square in. The water is constantly stirred and the temperature is taken at interval of 1 minute by means of a differential thermometer. Here if you see the food that is kept here in the form of a pellet or a capsule gets burnt and it releases energy. So that is being

28:41 measured in this thermometer. [snorts] After the initial temperature of water is determined, the sample is ignitated or burnt by means of an electric fuse until the pellet under goes a rapid and the complete oxidation. So once the pellet is burnt it liberates heat and that is absorbed by the water in which the bomb is in immersed and this results in the raise in the temperature which is accurately determined. So [snorts] this is the major concept of bomb calorimeter. So once the food here is ignited h by means of an electric fuse this has to undergo complete uh oxidation. After the

29:26 complete oxidation, the energy will be liberated and that will be absorbed by the water in which the bomb is immersed here and that raise in the temperature is being measured by this thermometer and that gives you the accurate values of the energy being liberated by that particular food item. So when I spoke about bomb calorometer, indirect calorimeter, direct calorimeter, how do we identify the energy requirements? These are some of the techniques by which the energy requirement of an individual can be measured. So the dietary reference intake or the DRRi value for energy is estimated as

30:13 estimated energy requirement which is nothing but EER is defined as an average dietary energy intake predicted to maintain the energy balance in an individual of a defined age, sex, weight, height and the level of physical activity that they undergo and different life stages from uh infancy to old age whether they are consistent with the maintaining the health. If you see there are different uh uh factors that are involved in the energy measuring the energy requirement of a person. The energy requirement of an infant and children is defined as amount of energy food energy needed to a total balance of the energy expenditure. So what you consume which versus what you expend or

31:00 expenditure of the energy is the desirable uh to a desirable level of physical activity and to support the optimal growth and development. So if you see uh we are going to talk about the energy balance which is nothing but the amount of food energy that you consume and the release of the energy from by way of physical activity and all that. So when we talk about energy requirement, we are going to go through the different life stages. Starting with infants in healthy child doubles its birth weight by 6 months. Therefore the energy requirements per kg body weight are higher in infants. So if you see ICMR which is nothing but the Indian Council of Medical Research places the energy

31:46 requirements for infants at 92 kilo calorie per kg body weight for up to 6 months and from 6 to 12 months it is 80 kilo calorie per kg body weight. There is a lesser uh uh calorie from 6 to 12 months because the activity is more after 6 months the child may be able to uh turn upside down and the child starts to crawl and the child starts to walk and all that. So the activity is also considered that way for children from 1 to 10 years. If you see uh the growth is uh generally slower compared to the infant age which is from 0 to 1 months but the activity is increased in these years. So they start running walking and they move do their physical activity. So [snorts] therefore

32:32 the energy requirements have to be estimated based on their growth and the activity. So that is for the children from 1 to 10 years. Similarly, if you see for children from uh 10 to 17 years, there are uh this is the major uh growth spurt that happens during u boys and girls where you can see the pubertal growth spurt needs to be considered for estimating the energy requirements. The nutrient needs are higher during the 12 to 5 15 years in boys and for girls it is 10 to 13 years. So that's the major uh growth spot that happens during the childhood uh adolescent period. [snorts] When we move on to the pregnant uh women

33:19 or the pregnant condition, there is an additional energy that is required during pregnancy for the growth of the placenta, the fetus, the maternal tissues and the activity levels of the pregnant women. So you can see uh pregnant women needs an additional requirement of uh calories throughout the pregnancy. Whereas for lactation women for the first 6 months and the next 6 months there will be a variation in the energy levels. Also the nutritional requirements of a lactating mother uh in terms of calories are basically increased with regard to the pregnant women as lactating mother needs more energy for uh entire milk production. So there will be a increase in the calories for the

34:05 first 6 months because that's going to be the exclusively breast uh feeding uh during the first 6 months and for the next 6 months there will be a little uh lesser uh calorie requirements for the uh lactating women. For the older age if you see uh after 60 years the BMR gets decreased due to the decrease in the muscle mass and there will and increase in the fat mass. So there will be a BMR decrease and uh the calorie requirement thereby since the BMR is also decreased the calorie requirement also should be decreased in such instances. So the old age is where the BMR is decreasing so the calorie also should be decreased. So coming to the uh energy RDA by body weight. So only based on the recommendations we have to plan the diet

34:52 accordingly. So this is very important uh uh when it comes to the body weight loss will be achieved uh only if you take 20 to 25 kilo calorie per kg body weight. For example, if a person's body weight is uh 80 calories uh sorry 80 kgs uh body weight and the person has to consume 20 to 25 that means roughly 1,600 calories for a weight maintenance. If somebody wants to maintain the weight and they know their body weight is perfect and they have they have to maintain this so please go for 30 to 35 kilo calorie per kg body weight. For example, if somebody is 60 kgs and go for 30 it is 1,800 kilo calorie per kg. For a person who needs

35:40 to gain weight that means the person is uh on the weight is lower side and you want to give them more calories then only they will put on weight. >> [snorts] >> For example, if a person is 40 calories or to 50 calories, so 50 kgs, sorry, 40 to 50 kgs, I am taking as 50 kg. So 40 calories you can give, which is roughly about 2,000 kilo calories that you are going to give to the person. So that is how it is it when it is comes to the energy RDA by body weight. These are some of the u information that I would like to share when it comes to the body weight uh per se. Uh with this uh the energy chapter is over. Next we move on to the other uh m macronutrients in the

36:28 next upcoming sessions. Thank you and happy learning.