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The energy balancing act Unit 1
- 1. The Energy Balancing Act Aw eso me .2 Cen t s! What’s it all about?
- 2. In this lesson, we will discuss… An introduction to Energy Balance What determines the energy in and energy out components What happens with energy imbalances over time? Tips to maintain energy balance 2 2012 Copyright PBRC
- 3. Energy Balance Why is this important? Energy balance it’s like a scale Seesaw Energy input Energy output 3 2012 Copyright PBRC
- 4. Energy Input Where is it coming from? Your energy input is the food that you eat – Calories coming from our food Calories (energy) provided by 3 macronutrients – Fat – Carbohydrate – Protein 4 2012 Copyright PBRC
- 5. Energy Input The Macronutrients 1 gram fat = 9 kcal 1 gram carbohydrate = 4 kcal 1 gram protein = 4 kcal 5 2012 Copyright PBRC
- 6. Types of fat Saturated – solid at room temperature (butter, lard), causes hardening of arteries. Unsaturated fat – liquid at room temperature (oils). Trans fat – Produced during food processing, occurs in ready - made foods such as cakes, crackers. Increases bad cholesterol in the blood. 6 2012 Copyright PBRC
- 7. Energy Input Calculating % of Calories from Macronutrients In one serving of pizza (technically 2 slices), there are: – 280 kcal – 14 grams of total fat – 28 grams of carbohydrates – 13 grams of protein What % of calories come from fat, 45% from fat; 40% carbohydrates and protein from carbohydrates; in this example? 19% from protein 7 2012 Copyright PBRC
- 8. Energy Input Calculating % of Calories from Macronutrients On Monday, Jane consumed: – 1,800 kcal Remember that there are: – 65 grams of fat 9 kcal per gram of fat – 240 grams of carbohydrates 4 kcal per gram of carbohydrate – 55 grams of protein 4 kcal per gram of protein What percent of calories come from fat, carbohydrate, and 8 protein? 2012 Copyright PBRC
- 9. Energy In How Many Calories? Nutrition Facts Label – Serving size – Number of servings per container – Calories – Total fat – Total carbohydrates – Protein 9 2012
- 10. Energy Output The calories you burn each day 5- 10% 3 components: Thermic effect of food – Basal metabolism – Physical activity – Thermic effect of food basal metabolism 25- 35% Physical 60- 65% Physical Basal activity activity Thermic effect metabolism of food 10 2012 Copyright PBRC
- 11. Energy Out Basal Metabolism Basal metabolism or Basal Metabolic Rate (BMR) Defined as the amount of energy required to support the operation of all internal body systems at rest except for digestion. – Usually the largest part of energy output for most people 11 Copyright PBRC
- 12. Basal metabolic rate What affects it? Contributing factors: – Body structure – Body composition – Gender Large muscle mass = higher BMR – Age 12 Copyright PBRC
- 13. Basal metabolic rate What affects it? Other factors: – Temperature (fever) – Thyroid gland secretion – Diet type – Periods of growth 13 2012 Copyright PBRC
- 14. Physical Activity Highly variable from person to person How much will you burn? – Body size – Muscle movement 14 Copyright PBRC
- 15. Energy Cost for Various Physical Activities Activity Calories used per hour Sleep 60 Sedentary activities 80 to 100 Such as reading, eating, watching television, sewing, playing cards, using (average = 90) a computer, studying, other sitting activities. Light activities 110 to 160 Such as cooking, doing the dishes, ironing, grooming, walking slowly, more (average = 135) strenuous sitting activities Moderate activities 170 to 240 Such as walking moderately fast, making beds, light gardening, standing (average = 205) activities requiring arm movement Vigorous activities 250 to 350 Such as walking fast, bowling, golfing, yard work (average = 300) Strenuous activities 350 or more Such as running, dancing, bicycling, playing football, playing tennis, cheerleading, swimming, skiing, playing active games 15 2012 Copyright PBRC
- 16. Thermic Effect of Food About 5 to 10% of total energy output. Energy required for digestion and absorption. This includes the breakdown of foods in the intestinal track by enzymatic action, absorption into the bloodstream, the uptake by the intestinal cells, the transport by the lymphatic system, or via portal circulation in the liver. 16 Copyright PBRC
- 17. How Does Energy Balance Work?
- 18. So, Energy Balance looks like… Energy In Energy Out (Calories eaten) (Calories used) • What you eat • Basal metabolism • How much you eat • Physical activity • Thermic effect of food 18 Copyright PBRC
- 19. Am I in Energy Balance? Remember this: – Energy in > Energy out Weight gain – Energy in < Energy out Weight loss – Energy in = Energy out Weight maintenance Energy In Energy out 19
- 20. Basal metabolic rate calculator Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years ) Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year ) 20 2012 Copyright PBRC
- 21. Let’s calculate BMR Sue 18 yrs, 5’ 4”, 145 lbs, Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years ) Sue = 655 + (4.35 x 145) + (4.7 x 64) - (4.7 x 18) = 665 + 630.75 + 300.8 – 84.6 = 1511.99 ~ 1512 21 2012 Copyright PBRC
- 22. Harris Benedict Formula To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows: If you are sedentary (little or no exercise) : Calories = BMR x 1.2 If you are lightly active (light exercise/sports 1-3 days/week) : Calories = BMR x 1.375 If you are moderately active (moderate exercise/sports 3-5 days/week): Calories = BMR x 1.55 If you are very active (hard exercise/sports 6-7 days a week) : Calories = BMR x 1.725 If you are extra active (very hard exercise/sports & physical job) : Calories = BMR x 1.9 22 2012 Copyright PBRC
- 23. Let’s calculate energy expenditure Sue: Sleep = 9 hrs, Light activity = 6 hrs, Sitting in class = 5 hrs, Homework = 2 hrs, Walking = 2 hrs. Total = 24 hours Sue EE = (9/24 x BMR) + (6/24 x BMR x 1.375) + ( 7/24 x BMR x 1.25) + (2/24 x BMR x 1.55) = (9/24 x 1512) + (6/24 x 1512 x 1.375) + (7/24 x 1512 x 1.25) + (2/24 x 1512 x 1.55) = 567 + 519.75 + 551.25 + 195.30 = 1833.3 ~ 1833 23 2012 Copyright PBRC
- 24. The Truth About Physical Activity People are much too inactive. Only 4 in 10 women are engaging in the recommended levels of activity. Activity is influenced by: – Age – Gender – Income status – Education status Source: CDC. Behavioral Risk Factor Surveillance System, 2001. Photo from: http://womenshealth.gov 24 2012
- 25. The Benefits of Exercise Strengthens your cardiovascular and respiratory systems Keeps bones and muscles strong Helps to manage weight Helps to prevent or manage diabetes Helps to ease depression and manage pain and stress Lowers your risk for developing certain cancers Helps you to sleep better 25 2012 Copyright PBRC
- 26. Inactivity Leads to a loss of muscle, to obesity, and to reduced functional ability. Increases the risk for cardiovascular disease, diabetes, and some cancers. Individuals who are physically fit can do more things, have better endurance for activities and tasks, and are healthier than individuals with low fitness. Try to incorporate small changes into daily activities. 26 2012 Copyright PBRC
- 27. Energy Imbalance Contributing to Weight Gain Consuming more energy (calories) than what you use will lead to weight gain over time. Accumulation of 3,500 kcal = 1 lb gain Increasing trend in today’s society – Portion sizes – Convenience foods – Sedentary activities (watching TV, video games) How do we overcome this? 27 2012 Copyright PBRC
- 28. Recommendations for Physical Activity Engage in at least 60 minutes of physical activity on most, preferably all, days of the week. 28 2012 Copyright PBRC
- 29. Now, to Review what we have learned… Going on a weight-loss diet is an example of creating an intentional energy deficit. --True or False-- True. If you are going on a weight-loss diet, you are either reducing the calories that you eat, exercising, or both (likely both)– in which case, yes you would be creating an energy deficit because your energy intake would be lower than output. 29 2012 Copyright PBRC
- 30. Now, to Review what we have learned… Energy deficiency occurs when energy output is less than energy intake (or in other words, energy input > energy output) output --True or False-- False. An energy deficiency arises when you are not consuming enough calories. In which case, your energy input would be less than your energy output, not the opposite. 30 2012 Copyright PBRC
- 31. Now, to Review what we have learned… Energy deficiencies may be caused by poverty, famine, illness, or dieting. --True or False-- True. Any of these instances could lead a person to consume less energy than what they are required to consume. Some are by choice (dieting), and others are a consequence of the situation (poverty, famine, illness) 31 2012 Copyright PBRC
- 32. Now, to Review what we have learned… An excess of 2,400 calories in the diet leads to one pound of stored body fat. --True or False-- False. It is an excess of 3,500 calories in the diet that leads to one pound of stored body fat. And, remember, that this is a cumulative excess. It doesn’t have to occur within a specified time frame. 32 2012 Copyright PBRC
- 33. Now, to Review what we have learned… Just a small daily energy excess can result in a number of added pounds of body fat over a period of years. --True or False-- True. Remember the example of eating one extra candy car each day. In less than 2 weeks, this could lead to one additional pound of body fat, and over the course of 1 year, nearly 30 pounds of additional body fat. 33 2012 Copyright PBRC
- 34. Now, to Review what we have learned… The more excess fat a body has, the greater the risks for health problems. --True or False-- True. The more body fat that you have over the recommended amount, the greater your risk for health problems. Also, the location of body fat is important. Body fat centralized around the abdomen is a greater risk factor that body fat centralized around the hips. 34 2012 Copyright PBRC
- 35. Division of Education Authors: Phillip Brantley, PhD, Director Heli Roy, PhD, RD Pennington Biomedical Research Center Shanna Lundy, MS Steven Heymsfield, MD, Executive Director The Pennington Biomedical Research Center is a world-renowned nutrition research center. VISION Our vision is to lead the world in eliminating chronic diseases. MISSION Our mission is to discover the triggers of chronic diseases through innovative research that improves human health across the lifespan. We are helping people live Well Beyond the Expected. The Pennington Center has several research areas, including: Clinical Obesity Research Experimental Obesity Functional Foods Health and Performance Enhancement Nutrition and Chronic Diseases Nutrition and the Brain Dementia, Alzheimer’s and healthy aging Diet, exercise, weight loss and weight loss maintenance The research fostered in these areas can have a profound impact on healthy living and on the prevention of common chronic diseases, such as heart disease, cancer, diabetes, hypertension and osteoporosis. The Division of Education provides education and information to the scientific community and the public about research findings, training programs and research areas, and coordinates educational events for the public on various health issues. We invite people of all ages and backgrounds to participate in the exciting research studies being conducted at the Pennington Center in Baton Rouge, Louisiana. If you would like to take part, visit the clinical trials web page at www.pbrc.edu or call (225) 763-3000. 35 2012 Copyright PBRC
Hinweis der Redaktion
- Say: Energy balance--What’s that got to do with me? The truth is that energy balance is an important concept for everyone to learn about—no matter how old or how young you are. First, we need to go over what we mean by balance? You can view energy balance the same way that you would view a scale, or even a seesaw. For example, What would happen if you were at a playground and decided to go and sit down on one side of an unoccupied seesaw? Do: Encourage students to answer. (Answer = that side of the seesaw will fall to the ground) Say: So, the seesaw would be out of balance, right. You would need someone else to come and sit on the other side. You find someone to come and sit down, but they are much heavier than you are. What happens to your side? Do: Encourage students to answer. (A= your side goes higher because you weigh less) Say: Again, the seesaw is out of balance. Next, you put your feet on the ground to hold yourself in place. Your friend steps off and lets another friend on. This friend weighs basically the same as you. As you lift your feet back up off of the ground, What happens now to your side? Do: Encourage students to answer. (Answer = it becomes level with your friends side). Say: This seesaw example is a lot like how energy balance is—except instead of people on either side of the seesaw (or scale), we have energy input on one side and energy output on the other. But what does that mean? What determines how much input you’ll have and what determines how much output? This is the very thing that we will go over next.
- Energy Input – Where is it coming from? Say: One side of the energy balance equation looks at the foods that you consume. This is your energy input (calories going into your body). Remember in the last lesson when we collected 24-hour dietary recalls from a person that we interviewed? Well, if I had asked you to total up all of the calories from each of the different foods and drinks that that person ate, this would have given us his/her energy input for that day. Everyone needs to eat food in order to survive. It is through the metabolism of nutrients found in the foods that we eat that we receive chemical energy to operate our bodies, but of course—we need to balance what goes in (energy input) our body with goes out (energy output), or else we’ll have all of this excess energy in our bodies. Can anyone tell me what the 3 macronutrients are in our diets (meaning the three nutrients found in food where we derive our energy from)? Do: Encourage students to answer. (Answer= carbohydrates, protein, and fat) Say: For most people, about 43 to 58 percent of daily calories come from carbohydrates, about 30 to 45 percent of calories come from fats, and about 12 percent come from proteins. You might ask, how do I know how many calories from fat, carbohydrate, and protein I consume for a given day? I will provide an example on how to do that in just a moment.
- Say: The first thing that you need to know is how many calories each gram of fat, protein, and carbohydrate supplies. What is the first thing that you notice on this slide that is different between fat and the other two nutrients, carbohydrates and protein? Do: Encourage students to answer. (Answer = fat provides more kcal for every gram that is consumed than does carbohydrate or protein [or it is more energy-dense than protein or carbohydrates]). Say: It is true that fat is more calorie (or energy)-dense than carbohydrate and protein. But, this most definitely does not mean eliminate fat altogether from our diets. We won’t really go into much detail about it in this lesson, but know that fat is an important component of our diet that has many important roles in the body. The type of fat that we eat [ trans and saturated vs. unsaturated fats] is very important, even more so than the amount, although we do still want to keep our intakes of fat at moderate levels
- The types of fat in our diet are: Saturated – solid at room temperature (butter, lard), causes hardening of arteries. Solid fat also increases risk for diabetes and hypertension. Unsaturated fat – liquid at room temperature (oils). Liquid fats are monounsaturated or polyunsaturated. Some of the healthiest diets contain mainly unsaturated fats that are heart healthy and do not increase the risk for diabetes. Trans fat – Produced during food processing, occurs in ready - made foods such as cakes, crackers. Increases bad cholesterol in the blood. Trans fats are worse in terms of heart disease risk than saturated fats.
- Say: Raise your hand if you like pepperoni pizza. (allow students time to respond). Raise your hand if you have ever had Tombstone pizza before. (allow time to respond). For our example, we will look at the percent of calories from total fat, carbohydrates, and protein in 2 slices of Tombstone Pepperoni Pizza. In one serving of pizza (which is technically 2 slices), there are: 280 kcal 14 grams of total fat 28 grams of carbohydrates and 13 grams of protein Say: The first thing that we will do is to calculate what percent of energy comes from fat in one serving of th pizza. If there are 9 kcal for every gram of fat, then we need to multiply the amount of fat found in the 2 slices of pizza (which is 14 grams of fat) times 9. So, that would be 14 times 9. Do: Write on the board 14 grams of fat x 9 kcal/gram of fat = 126 kcal . Also, be sure to indicate to the students that grams of fat cancel out and that you are left with calories only. Say: What we just figured up was the number of calories in 2 slices of pizza that came from fat. Next, we need to know the actual percent of calories that came from fat. We would do this by dividing the number of calories from fat by the total calories in the serving of pizza that we ate. This would be 126 divided by 280. Do: Write on the board (underneath the last part) 126 kcal/280kcal = 0.45 Say: We get a decimal of 0.45. Does anyone know what we need to do to make this a percent? Do: Encourage students to answer. (Answer = multiply the decimal by 100) Say: Yes, and once we do this, we find that in this meal, 45% of the calories came from fat (total fat). Next, we will calculate the percent of calories from carbohydrates in this meal. Remember, that there are 4 kcal for every gram of carbohydrates. In this example, the meal (which is 2 slices of pizza) has 28 grams of carbohydrates. So, we need to multiply the total grams of carbohydrates in this meal times 4 (28 times 4). Do: Write on the board 28 grams of carbohydrates x 4 kcal/gram of carbohydrate = 112 kcal . Note that when you multiply, grams of carbohydrates cancel out, and you are left with kcal only. Say: We find that there are 112 calories from carbohydrates in this meal. Next, we need to figure up what percent of calories came from carbohydrates. We do this by dividing the number calories provided by carbohydrates in our meal by the number of total calories in the meal. This is: 112 divided by 280. Do: Write on the board: 112 / 280 = 0.40. Say: Once we multiply this decimal by 100, we find that 40% of the calories in this meal are from carbohydrate. Finally, we will calculate the percent of calories in this meal from protein. Remember, that like carbohydrates, protein also has 4 kcal per gram. In this meal, there are 13 grams of protein, so in order to determine the number of calories from protein we would need to multiply 13 grams of protein by 4 kcal. Do: Write 13 grams of protein x 4 kcal/gram of protein = 52 kcal on the board. Again, note that grams of protein cancel out, leaving you with kcal only. Say: In this meal, there are 52 kcal from protein. To calculate the percent of kcal from protein in this meal, we need to divide 52 kcals (calories from protein in the meal) by the total number of calories in the meal, 280. Do: Write 52/280= 0.1857 Say: When we multiply this decimal by 100, we get an answer of 18.57 which can be rounded to 19%. This tells us that 19% of the calories in this meal come from protein.
- Say: Now, we are going to calculate how many calories came from fat, carbohydrates, and protein in another example. But this time instead of using a meal as an example, we will use an entire days worth of meals and beverages. Here is our example: On Monday, Jane consumed 1,800 calories, 65 grams of fat, 240 grams of carbohydrates, and 55 grams of protein. I’m going to give you a handout with this information on it, and will allow you time to work through it. Remember what we learned: 1 gram of fat = 9 kcal; 1 gram of carbohydrate= 4 kcal and 1 gram of protein = 4 kcal. If you have any questions, just let me know. Do: Pass out the Calculating Percent Energy from total fat, carbohydrates, and protein handout. Allow students time to work through the example. Walk around the room and assist any student having problems. Here is how to work the example through: 65 grams of total fat. 65 g of fat x 9 kcal/g fat = 585 kcal. This means that 585 kcal came from fat for that day. Next, divide the number of calories from fat by the total number of calories consumed for the day. 585/1,800= 0.325. After you multiply this decimal by 100; you find that 32.5% of calories came from fat in Jane’s diet on Monday. 240 grams of carbohydrates. 240 g of carb x 4 kcal/g carb = 960 kcal. This means that 960 kcal came from carbohydrates for that day. Next, divide the number of calories from carbohydrates by the total number of calories consumed for the day. 960/ 1800 = 0.53333. After you multiply this decimal by 100 and round, you find that 53% of calories came from carbohydrates in Jane’s diet on Monday. 55 grams of protein. 55 g of pro x 4 kcal/g pro = 220 kcal. This means that 250 kcal came from protein for that day. Next, divide the number of calories from carbohydrates by the total number of calories consumed for the day. 250/1800 = 0.138889. After you multiply this decimal by 100 and round, you find that 14% of calories came from protein in Jane’s diet on Monday. ** When it looks like students are done with the exercise, continue** Say : Does anyone know the percent of calories that Jane consumed from fat? (Answer= 32.5%). What about the percent of energy from carbohydrates? (Answer= 53%) And, finally—what about the protein? (Answer= 14%). When you add those percents up, the total should be at or very near 100 %.(32.5 + 53.0 + 14 = 99.5). And, for our example, we find that it is! Say: So, did Jane follow the Dietary Guidelines for Americans’ recommendations for fat intake? (Answer = yes, 32.5% falls within the range of 25 to 35%). What does everyone think will happen if Jane continues to eat fewer calories than recommended? (Answer = with time, she will lose weight). We will go over this in more detail in just a little while. And, finally does anyone know which side of the scale corresponds to the 1,800 calories that Jane consumed? (answer = “A”).
- Say: You might ask, “How do I know how many calories I am consuming each day?” Luckily, there is an easy answer. For most foods that you eat, the food package will show a nutrition facts panel. The nutrition facts panel provides information about calories, fat, carbohydrates, protein and other nutrients contained in the food. You can even find nutrition facts panels on the package of most meat that is purchased (like ground beef, chicken breasts, etc) in the meat section at your local grocery store. The only thing that might be a little hard to find information on is fresh produce, although some stores are starting to list this information at the produce section. Here is an example of a nutrition facts panel. This example is for a small container of fat-free milk. One important thing that I must point out is the serving size and number of servings per container of package. Understanding how many calories you are actually consuming can be tricky unless you understand this part. In red , we have highlighted the serving size found in this beverage. It is 8 ounces, or 1 cup. Everything listed below this--- calories, total fat, carbohydrates, protein, etc—is pertaining to how much of each nutrient is found in one serving, but there is not just one serving in this container. If you look at the part highlighted in blue , you will see that there are two servings of milk in the container. Therefore, if you were to drink the entire container, you would be consuming not one but rather two servings, and would have to multiply the calories, along with everything else listed below, by two. From looking at this nutrition facts panel that I have here, Can anyone tell me how many grams of total fat are found in ONE serving of skim milk? (Answer = zero grams) Yes, skim milk contains no fat. Can anyone tell me how many grams of total carbohydrates are found in ONE serving of skim milk? (Answer = 12 grams) What about in TWO servings? (Answer = 24 grams) Can anyone tell me how many grams of protein are found in ONE serving of skim milk? ( Answer = 8 grams) What about in TWO? (Answer = 16 grams).
- Say: Now we know how to calculate the number of calories (and amounts of fat, carbohydrates, and protein) that we consume from foods, and as we said earlier, this is what contributes to energy input -- the energy that goes into our bodies from the food that we eat! Next, we will talk about the other side of the scale (or seesaw) of energy balance—and that is energy output . Energy output deals with the amount of calories (energy) that you use each day. There are three factors that account for the calories you use each day and these are: Basal metabolism Physical activity (and the) Thermic effect of food Basal metabolism makes up the largest portion of energy output, followed by physical activity and then the Thermic effect of food. I think that of these three terms, we are more likely to be familiar with physical activity—but in just a while, we will be familiar with basal metabolism and Thermic effect of food, too. Let’s start with basal metabolism.
- Say: No matter how still your body is, internal activity always continues—even while you are asleep. While resting, your brain and liver, two very important organs, use about 40% of your body’s energy. Your lungs, another important organ, also have to continue working to supply your tissues with oxygen. Basal metabolism can be defined as the amount of energy required to support the operation of all internal body systems except for digestion . It includes the energy your body uses every day to breathe, circulate blood, and maintain nerve activity. Things like secreting hormones, maintaining body temperature, and making new cells are also part of basal metabolism. The rate at which your body uses energy for basal metabolism is known as your basal metabolic rate (BMR). An equation called the Harris benedict equation is used to calculate energy needs. Harris-Benedict equation gives us our BMR or BEE (basal energy expenditure). Harris Benedict equation does not account for physical activity. That’s because physical activity is not a portion of your BMR. It is a separate concept
- Say: So, if the BMR is the largest slice from the pie of energy output, then what predicts our BMR ? There are actually many factors which effect BMR, some of which include: your body structure (height), body composition, and gender . (Body structure) A tall person will have a higher BMR than a short person because the tall person has more body surface area through which heat is lost. Body composition refers to the percent of different tissues in the body, like: fat, muscle, and bone. Someone with a high proportion of muscle will have a higher BMR than someone with more fat tissue. This is because it takes more calories to maintain muscle tissue than it does for fat. This means that muscle is more metabolically active . (Gender) Males will generally have a higher BMR than females since males have more lean body mass than do females. Age is another factor. As you grow older, your BMR tends to decline. There is actually a 5% decrease in BMR for every 10 years past the age of 30.
- Basal metabolic rate What affects it? Say: There are other factors which influence BMR. These include: body temperature, thyroid gland secretion, low calorie diets, and periods of growth . Body temperature is one factor. Temperature, both inside and outside of the body, can adjust your BMR. For example, fever increases BMR. Thyroid gland secretion is another factor. The thyroid gland secretes a hormone known as thyroxine, which regulates basal metabolism. In some instances, people have an overactive thyroid gland, which secretes too much thyroxine, in which case—these people have a high BMR. The opposite can also be true. Some people have an underactive thyroid gland, in which case not enough thyroxine is released causing a lower BMR. The calorie content of your diet can also influence your BMR. A diet that is very low in calories actually decreases your BMR by about 10 to 20%. This is because your body views this as a period of famine and tries its best to effectively operate on what is available. In simple terms, the body lowers its energy need to try its best to still do the essential functions. This is why someone restricting calories only (and not exercising) may have a hard time reaching weight goals. Exercise is an important part of any weight loss goal. Finally, periods of growth can also change the BMR. During growth, BMR are higher. This is true during infancy, childhood, and teen years, when the body is growing and expanding—and also during pregnancy. As you probably noticed, there aren’t many factors that we’ve discussed that you can change. However, there is one way that you may be able to impact your BMR; and that is, by adding regular physical activity into your lifestyle. This can help you develop more muscle, and as we said, higher muscle mass means a higher BMR.
- Physical Activity Say: The second category of energy output is the energy you use for physical activity. All exercise burns calories for they involve movements and energy is required for every movement made. The calorie burning ability of each exercise depends on the speed and/or force at which the exercise is performed. This proves the calorie burning potential of an exercise can be increased depending on an individual's effort for that movement. Anyone can apply the process of burning more calories by simply increasing the effort in each exercise. The amount of energy that you burn during an exercise depends on: your body size and the actual movement of your muscles . The larger the body size, the more energy you will need in order to make the muscles work. With that said, we would expect a 220-pound woman to burn more calories while walking than a 150-pound woman walking at the same pace. The amount of muscle movement that you do during exercise also influences how many calories you will burn. Swinging your arms while you walk will cause you to burn more calories than if you walked keeping your arms at your sides.
- Say: On this slide, you will see the energy costs for various activities. Activities are separated based on intensity, where the top represents those that burn the least number of calories, and the bottom represents the most strenuous of all activities. Like I had mentioned earlier, you are always using calories. Even when you sleep. Who would have thought that for every hour that you sleep, you burn 60 calories. Of course you would have to do more physical activity than just sitting and sleeping, or else you would not have a very large energy output. Be sure to note that the calories used column represents how many calories are used per hour of engaging in a particular activity. So, if you only did an activity for 15 minutes (or ¼ of an hour), then you would have to divide the number that you look up on the chart for that activity by 4. Do: Read over each type of activity and state examples of each. Sleep 60 Sedentary activities such as reading, eating, watching television, sewing, playing cards, using a computer, studying, other sitting activities. 80 to 100 (average = 90) Light activities such as cooking, doing the dishes, ironing, grooming, walking slowly, more strenuous sitting activities; 110 to 160 (average = 135) Moderate activities such as walking moderately fast, making beds, light gardening, standing activities requiring arm movement; 170 to 240(average = 205) Vigorous activities such as walking fast, bowling, golfing, yard work; 250 to 350 (average = 300) Strenuous activities Such as running, dancing, bicycling, playing football, playing tennis, cheerleading, swimming, skiing, playing active games; 350 or more A few ways to burn more calories when exercising: exaggerating each movement in the exercise will help in burning more calories exercising the major muscle groups such as legs, back, & buttocks can help for burning calories exercises such as jogging, walking, dancing require extra energy for balance so can be better for burning calories than cycling or rowing burning calories will be increased when movements in an exercise are continuous Caloric expenditure levels: 1. Sitting and other sedentary activities Energy expended is the least. This is a little more than basal metabolic rate. The increased expenditure comes from increased brain activity by consciously interpreting what was seen or read. Increased brain activity burns mostly carbohydrates however many other metabolic processes will use fat to fuel the processes. At an estimate, this activity will burn 1-2 calories per minute which is very low even though up to 80% will come from muscle burning fat! 2. Light housework - (i.e. dusting or washing up) These activities also burn little total calories - around 2-3* calories per minute . Around 70%* of calories burned comes from fat. 3. Moderate activities - Walking Walking, gardening, standing with movement are moderate activities. About 55% of calories comes from fat. Walking not only burns a good proportion of stored fat it can also burn a large amount of calories especially performed for longer durations and at a brisk pace. Walking is a great activity for people of any age. 4. Vigorous activities - Aerobic exercise or light Jogging Aerobic classes, jogging, most aerobic activities, such as stair stepping, elliptical, or jogging on the treadmill are vigorous activities. The percentage of calories from fat is at 30%. 5. Strenuous activities - Running (7 minute mile average) Running a mile in 7 minutes will burn more than 10 *calories per minute. At this rate, about 80% calories comes from carbohydrates and only 20% from fat. Say: Next, I will hand out an assignment so we can put what we have learned about physical activity to the test. It will be a list of all activities that were done over a 24-hour period by a person. All that you have to do is figure up: The total time spend doing each activity, Decide which type of activity it is (light, moderate, etc) and then Determine how many calories that exercise used for that given amount of time. Be sure to use the average amount of calories used per hour when it is listed, too. Do: Pass out the Physical activity handout. Say: I want everyone to learn how to do this on their own, but feel free to get help from a friend if you are stuck. You can also ask me for help if you have any questions. ---------------------------------------------BREAK-------------------------------------------------- Do: Allow students time to work through the assignment. Walk around the room and assist any student who is stuck. When it looks like the students are done, proceed. Say: Can anyone tell me which one of Alyssa’s activities burned the greatest # of calories? (Answer = cheerleading) Which activity burned the least number of calories? (Answer = riding in the car) What was the total number of calories that she burned for the day? (Answer = ~3,049 kcal)
- Say: Your third need for energy is due to the Thermic effect of food. The Thermic effect of food is the energy required to complete the processes of digestion, absorption, and metabolism. It can be thought of as the energy required for digestion and absorption. This includes the breakdown of foods in the intestinal track by enzymatic action, absorption into the bloodstream, the uptake by the intestinal cells, the transport by the lymphatic system, or via portal circulation in the liver. Although it can differ slightly depending on the types and amounts of foods eaten, the Thermic effect of food is generally equal to only 5 to 10% of your combined basal metabolism and physical activity needs. So, if a person burned 2,200 calories for physical activity and basal metabolism, then they would spend about 220 calories for the Thermic effect of food (2200 x 0.10 [10 percent] = 220) About 5 to 10% of total energy output.
- Say: In the next section, we will talk about energy balance and imbalance—what would lead to either one of these situations.
- Say: Are you in energy balance? Well, you could figure this out by calculating your energy input – the number of calories that you consume on a given day and comparing this with your energy output—from physical activity, basal metabolism, and the Thermic effect of food. The less complicated way is to follow your weight over time. If you are gaining or losing weight, then you will know that you are not. If your weight remains relatively stable from week to week, and month to month, then you are. Your energy input would be relatively equal to your energy output. Of course, everyone’s weight fluctuates from time to time, but if you see your weight headed in a certain direction—either steadily up or steadily down, you will know that you are not in balance. There are two causes of energy imbalance and that is: consuming too many or too few calories . Consuming too many calories is referred to as energy excess, whereas consuming too few is referred to as energy deficient. In the U.S. we are usually more likely to consume too many than not enough calories.
- Say: The following is important to understand. The first equation in pink explains what contributes to weight gain, and that is – as you may have guessed, an energy input that is greater than your output. So, what does that mean? That means that you are consuming more calories than what you actually need. A seesaw of this example with energy input on one side and energy output on the other would have energy input weighing down one side. You’re consuming more calories than what your body needs. The second equation in blue explains what contributes to weight loss, and that is—an energy input that is less than your output. So, what does that mean? That means that you are not consuming enough calories to meet your energy needs. A seesaw of this example with energy input on one side and energy output on the other side would have energy input elevated much higher than energy output. You’re not consuming enough calories to meet your needs. Finally, the last equation in orange explains what contributes to weight maintenance, and that is an energy input that is equal to your output. So, what does that mean? That means that what you are consuming is matching what you are using. Weight maintenance is important because if you are already at a healthy weight, then you don’t want to lose or gain any extra weight.
- Say: There are ways of calculating basal metabolic rate without being measured by a respirometer. One of the ways is to use a standardized equation. There are many equations around to do this, and they are all fairly accurate to give us an idea of our energy needs. We will use these equations for men and women to calculate resting metabolic rate. Women : BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years ) Men : BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year )
- Say: As an example, we will use Sue who is 18 yrs, 5’ 4”, 145 lbs. I will show you the calculation using her information. Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years ) Sue = 655 + (4.35 x 145) + (4.7 x 64) - (4.7 x 18) = 665 + 630.75 + 300.8 – 84.6 = 1511.99 ~ 1512
- To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows: If you are sedentary (little or no exercise, mainly sitting, watching TV, reading) : Calories = BMR x 1.2 If you are lightly active (light exercise/sports 1-3 days/week) : Calories = BMR x 1.375 If you are moderately active (moderate exercise/sports 3-5 days/week): Calories = BMR x 1.55 If you are very active (hard exercise/sports 6-7 days a week) : Calories = BMR x 1.725 If you are extra active (very hard exercise/sports & physical job) : Calories = BMR x 1.9
- Say: Once we have basal metabolic rate, we can also calculate total energy expenditure on an individual once we know how many hours of a type of activity they engage in. In our example, Sue has the following activity pattern: Sleep = 9 hrs, Light activity = 6 hrs, Sitting in class = 5 hrs, Homework = 2 hrs, Walking = 2 hrs. Total = 24 hours We can now plug our information in the equation and find our total energy expenditure. Sue BMR = 1512 Sue EE = (9/24 x BMR) + (6/24 x BMR x 1.375) + ( 7/24 x BMR x 1.25) + (2/24 x BMR x 1.55) = (9/24 x 1512) + (6/24 x 1512 x 1.375) + (7/24 x 1512 x 1.25) + (2/24 x 1512 x 1.55) = 567 + 519.75 + 551.25 + 195.30 = 1833.3 ~ 1833 Sue’s energy expenditure is 1833 Calories in 24 hours at her normal activity level.
- Say: As I just mentioned, Americans are not exercising as much as they should be, and physical activity is a big piece to the puzzle of energy balance. Even if you aren’t trying to lose weight, it is very important not only because of the benefits that it provides, but also because it increases your energy output; allowing you to consume more calories each day (energy input) without gaining weight, and if you are trying to lose weight, combining dietary efforts (lower calorie food choices) with exercises greatly improves the odds that you will be successful. From a survey taken in 2001 in the United States, we see that only 4 out of 10 women are engaging in the recommended levels of physical activity. Physical activity has been shown to be influenced by age (where activity is shown to decline with age), gender (where males are more likely to exercise than are females), income status and education levels, where those with less education and income are less likely to exercise than those with higher income status and education levels.
- Say: So, what are the benefits of exercise? There are many. One benefit is that exercise helps to strengthen your cardiovascular and respiratory systems . You may not understand why this is a huge benefit now, but know that cardiovascular disease is not something that just occurs over night—it is a gradual process that begins even in childhood. Doing things that are good for your heart now will definitely pay off later in life. Another benefit is that exercise helps to keep your bones and muscles strong . Regular exercise is one of the best things that you can do to keep yourself from getting the bone-weakening disease later in life, known as osteoporosis. Also, strong bones and muscles help you to have better balance and coordination. As we’ve already touched on, regular exercise also helps to manage your weight since it increases the calories that your body uses, better matching calories in with calories out. Maintaining a healthy weight is essential to prevent obesity and to prevent conditions such as arthritis later in life caused by extra weight on bones and joints. Exercise also helps you to prevent the development of diabetes or manage the condition if you already have it. For people with type 2 diabetes, a healthy diet combined with regular physical activity is essential to control their condition. Reoccurring elevated sugar levels in the blood from foods high in carbohydrate (high glycemic-foods) in people who are sedentary greatly puts you at risk for the development of Type 2 diabetes. Exercise is good not only for people who already have the condition, but also for people without the condition as it helps to lower their risks. Exercise lowers blood sugar levels in two ways. One is by pulling sugar from the blood to the muscles to use for energy both during and after exercise. The other is by helping to increase insulin’s sensitivity (ability to do its job). Insulin is the hormone responsible for regulating blood sugar. When it is working properly, it pulls blood sugar from the blood and into the cells where it can be used for energy. Exercise also helps to ease depression and manage pain and stress. It does so by activating neurotransmitters, which are chemicals used by nerve cells to communicate with one another. The activation of these neurotransmitters is associated with avoidance of depression. Exercise also activates endorphins, which are other neurotransmitters that produce feelings of “well-being” for natural pain and stress relief Exercise also helps to lower your risk for developing certain cancers . These cancers are: prostate, colon, uterine lining (endometrium), and breast. Exercise is believed to lower the risk of breast and endometrial cancer by reducing body fat and lowering the production of estrogen. Researchers are not quite as sure of how exercise helps to lower colon cancer, but they believed that it may have something to do with the fact that exercise helps digested food to move through the colon more quickly. How exercise helps to lower the risk for prostate cancer in men is at present, unknown. And, finally exercise can help you to sleep better. Moderate physical activity at least 3 hours before bedtime has been shown to help you relax and sleep better at night.
- Say:E xercise has many excellent benefits. But in order to receive these benefits, you must exercise. Physical inactivity leads to loss of muscle, reduced functional capacity, and can contribute to obesity over time. Exercise helps to protect us against the development of heart disease, diabetes, and certain kinds of cancer, so if you don’t exercise—then you are at greater risk for these diseases. It is true that individuals who are fit can do more things, have better endurance for activities and tasks, and are healthier than individuals of low fitness. You have to be a “star athlete” however. Regular physical activity of any sort has benefits. So, whether you are increasing your activity each day by walking a little more, doing some cleaning, or challenging your friends to a basketball game, remember that a little change goes a long way. Start out slow and gradually and build more exercise into your daily activities. And, don’t stress if you fall out of your routine on one day. Start out fresh again the next day
- Say: Be sure to remember that the Dietary Guidelines for Americans recommend that all children and adolescents should engage in at least 60 minutes of physical activity on most, but preferably all, days of the week.
- Say: Another big part is increasing physical activity. It’s hard to change our eating habits—these are something that we’ve learned from birth. Incorporating regular physical activity into your daily activities is another good option. And, remember no one expects you to completely change your lifestyle over night. It’s the drastic changes in our lifestyle that are the hardest to keep. It’s the small changes that we are able to live with and even small changes can add up in a big way over time. : Be sure to remember that the Dietary Guidelines for Americans recommend that all children and adolescents should engage in at least 60 minutes of physical activity on most, but preferably all, days of the week.
- Say: The statement on each of the slides in navy blue—asking students if they feel that the statement is true or false. Do: Encourage students to answer and ask them to say why they feel it is true or why they feel it is false (depending on their answer). Once you have received enough answers to proceed, press the space bar to reveal the answer, along with the explanation of why it is the right answer.