Chapter 8 Energy Balance and Body Composition

Transcription

1 8-1 Chapter 8 Energy Balance and Body Composition IF NOTHING ELSE, MY STUDENTS SHOULD LEARN 1. The general concept of energy balance in terms of equating energy input (i.e., food consumption) to energy output (i.e., basal metabolism and physical activity). This concept demonstrates that if energy consumed is greater than the energy expended, then body weight increases. If energy consumed is less than energy expended, weight decreases. 2. That people who are either overweight or underweight may be at greater risk at developing health related problems. For example, a strong relationship exists between obesity and cardiovascular disease, diabetes, and cancer. 3. There are several theories that have been proposed to explain obesity. These include both internal (metabolic disturbances, genetics) and external (food price/availability/advertising, physical inactivity) factors. 4. That eating disorders are very complex conditions that pose significant risk to maintain overall health. LEARNING OBJECTIVES Students should be able to: LO 8.1: Describe what energy balance is, in terms of the sources of energy input and energy output, and how it relates to body weight and overall health. [Understand/Apply] LO 8.2: Describe the different factors that can affect the energy in portion of the energy balance equation. [Remember/Understand] LO 8.3: Describe the role of basal metabolic rate in determining an individual s daily energy needs, and explain the other factors that determine energy need. [Understand/Apply] LO 8.4: Calculate the body mass index (BMI) when given height and weight information for various people, and describe the implications of their BMI for health. [Remember/Understand]

2 8-2 LO 8.5: Use equations and tables to estimate energy requirements. [Understand/Apply] LO 8.6: Discuss the importance of body fat in maintaining overall health with specific reference to the distribution of fat in the body. [Understand/ Remember] LO 8.7: Describe the different techniques that can be used to determine a persons body composition. [Remember/Understand] LO 8.8: Describe the numerous complications and risks involved with being overweight and physically inactive. [Remember/Understand] LO 8.9: Compare and contrast the characteristics of anorexia nervosa and bulimia nervosa, and provide strategies for combating eating disorders. [Understand/Analyze] W H Y I S T H IS C H A P T E R I M P O RTAN T T O S C I EN T ISTS A ND H E A LT H C A R E P R A C T I T I O N E R S? Of special interest to... symbol key: = Health Care Practitioners 2 = Science Majors Obesity is a health risk for the development of many chronic diseases. Health care practitioners recognize the dangers to developing obesity and actively consult with patients on effective management and preventive strategies to deal with obesity. Nutrition scientists are continually studying ways to prevent and/or treat obesity. Based upon the relationship between presence of body fat and the development of chronic disease, scientists have established what they feel is an ideal percentage of body fat. For males (and females), those less than 40 years of age the ideal amount is 22 percent (32%) and for those greater than 40 years of age, the ideal amount is 25 percent (35%). Central obesity may be more hazardous to health than other forms of obesity. Exercise scientists and health care practitioners are studying ways to alter central obesity by examining the effects of regular exercise programs with and without diet interventions. Scientists have linked obesity with a number of variables, which continue to be an area under investigation. These include factors such as birth order, number of brothers, marital status, onset of puberty, ethnicity, fast food consumption, proportion of fat/protein and carbohydrate intake, income, consumption of sugar sweeteners, leisure time, education level, sleep habits, alcohol consumption,

3 8-3 sedentary behaviour, television watching, and many more. Genetic scientists are identifying potential genetic links with obesity development. Many popular diets recommend high protein, low carbohydrate consumption. Nutrition scientists are studying the benefits and risks of consumption of such a diet, both on a short term and on a long term basis. Nutritionists who study human behaviour identify stimuli that could lead to overeating. Food pricing, availability, and advertising influence food choices. Both scientists and health care practitioners recognize that physical inactivity is clearly linked with the development of obesity. Various health care practitioners work with patients who develop eating disorders. In particular, young athletic women are prone to combining an eating disorder with the development of other conditions, such as amenorrhea and osteoporosis. WHY SHOULD STUDENTS CARE? Most obese people suffer illnesses, and obesity is considered a chronic disease. Experts estimate health risks from obesity using BMI values, waist circumference, and a disease risk profile. Fit people are healthier than others, regardless of their percent body fat. Being overweight presents social and economic handicaps as well as physical ills. Judging people by their body weight is a form of prejudice in our society. The energy in side of the energy equation, as measured in kcalories, refers to the amount of energy taken in each day in the form of food and beverages. The number of calories in foods and beverages can be obtained from published tables or computer diet analysis programs. People s energy needs vary greatly. No easy method exists for determining a person s energy expenditure. Two major components of energy expenditure are basal metabolism and voluntary activities. A third component of energy expenditure is the thermic effect of food. Students should be aware that the percentage of fat in a person s body can easily be determined by measuring skinfold thickness, body density, or other parameters. Body fat distribution can be estimated by radiographic techniques, and central adiposity can be assessed by measuring waist circumference. There are metabolic theories of obesity that attempt to explain obesity on the basis of molecular functioning. Students should realize that a person s genetic inheritance greatly influences the likelihood of obesity.

4 8-4 It is important for students to have a solid understanding of energy balance and fuel metabolism. When energy balance is negative, the breakdown of glycogen returns glucose to the blood. When body glycogen decreases, muscle protein starts to break down to produce glucose. Both prolonged fasts and low carbohydrate diets are ill advised. When energy balance is positive, carbohydrate is converted to glycogen or fat, protein is converted to fat, and food fat is stored as fat. Students should have a basic understanding of the principles of weight loss and gain. (1) Physical activity greatly augments diet in weight loss efforts and is associated with improvements in health and body composition. (2) Alternatively, weight gain requires a diet of calorie dense foods, eaten frequently throughout the day. (3) For people whose obesity threatens their health, medical science offers drugs and surgery. Students in nutrition should be aware of the main types of eating disorders, their treatment and prevention. These include the female athlete triad, (specific to athletes), anorexia nervosa, and bulimia nervosa. W H AT A R E C O M M O N S T U D E N T MISCONCEPTIONS/STUMBLING BLOCKS? 1. While trying to grasp the numerous factors that directly affect satiation and hunger, students often become overwhelmed. Following the pathway outlined in Figure 8 2 will help students make the link between some of these factors and the physiological basis for satiation and hunger. 2. Some students do not initially understand all of the components that contribute to energy expenditure (e.g., physical activity, thermic effect of food and basal metabolic rate). They most commonly stumble over what the thermic effect of food is, and some do not grasp the concept of basal metabolic rate. Having students calculate their own Estimated Energy Requirement (EER) helps to clarify this, as well as reviewing the various examples outlined in Table Often, students have difficulty remembering the calculations for body mass index (BMI). It is important for students to remember that it is based on body mass (expressed in kilograms) divided by height2 (based on metres). It also would be helpful to refer to benchmark values as outlined in Table There is a common misconception that low carbohydrate diets are the best for weight loss. Discuss the pros and cons of such diets in class. W H AT C A N I D O I N C L A S S? 4

5 8-5 There are a variety of activities that can be done in class. Listed below are some activities that will help introduce the topic of nutrition, and the students to each other. Classroom Activity 8 1: Chapter Opening Quiz Objective: Introduction to chapter Class size: Any Instructions: As a way of introducing any new chapter, give a quiz to the class. This is a quiz designed to be projected overhead. For details, please see Chapter 1, Classroom Activity 1 4. Classroom Activity 8 2: Visual Demonstration of Body Fat Key concept: Negative effects of fat; adipose tissue Class size: Any Materials needed: Fat models (equivalent of 2 5 kg [5 10 lb] body fat) Instructions: Purchase fat models that demonstrate visually the appearance of 2 5 kilograms (5 10 pounds) of body fat. Display in class when discussing negative health effects of excess body fat. Classroom Activity 8 3: Body Composition Assessment: Bioelectrical Impedance1 Key concept: Assessment of body composition Class size: Any Instructions: In an attempt to demonstrate the difference between body weight and body fat, body composition tools can be brought into the classroom. If available, obtain a bioelectrical impedance analysis (BIA) tool. This instrument is simple enough to be used in the classroom. It appears to be high tech as it has a computer and electrodes and, as a result, fascinates students. Student interest often generates questions and discussion and opens informal teachable moments. To begin the procedure, ask students to volunteer to have their body composition examined. It is wise to make this voluntary rather than required (be sensitive to issues of privacy in the event that a student declines). Next, determine the student s height and weight and enter that information into the computer. Instruct the student to lie down and place two pair of electrodes on the right side of the body (one pair on the foot and the other on the hand). Be sure to study the instructions provided for accurate placement. To enhance accuracy, the student should be well hydrated, should not have exercised within the previous six hours, and should not have eaten in the previous two hours. Conducting body fat measurements using fatfold calipers can also be done for comparison purposes. Limitations within all methods of determining body composition can be discussed. The strengths of the BIA include it can be performed quickly, it is noninvasive, and it is easy to transport. Unfortunately, the equipment can be expensive. Critical Thinking Questions2 These questions will also be posted to the book s website so that students can complete them online and their answers to you. 1 Adapted from L.O. Schulz, C. F. Douthitt, C. F., Bioelectrical impedance analysis: A research tool useful for classroom teaching, Journal of Nutrition Education, 22 (1990): 182D. 2 Contributed by Kathleen Rourke.

6 Discuss the differences between direct and indirect calorimetry. Give an example of each and provide information as to the importance in the difference between the two. Finally, define the thermic effect of food. Is this related to calorimetry? 2. What are important factors that you would assess in your patients with regard to appetite and achievement of energy balance? 3. You are working with two patients who are anxious to improve their health status through diet and exercise. Lucy is 5 9 in height and weighs 200 lbs. Lucy is 35 years old and is active with her family and her job. She tries to exercise about two times weekly but has a lot of stress in her life with young children and a full time job. Recently, she has not been feeling well and her whole family has promised to help her with family responsibilities so that she can take the time to increase her exercise and do what is necessary physically to feel better. Bob is a 55 year old who has had a successful career in marketing. At present, he weighs 225 lbs and is He walks occasionally with his wife and through airports to catch his flights, but otherwise admits he is a couch potato. As of late, his cholesterol is high and his physician is concerned about his cardiovascular health status. Calculate their BMR as well as their Estimated Energy Requirements. Discuss how you believe that you can help Lucy and Bob increase their BMR through your recommendations and their actions. 4. Determine your BMI. Is your BMI in a healthy range? If not, why not? Do you believe that measuring body fat percentage may more accurately reflect your body composition? Briefly discuss each body composition measure and discuss why measuring body fat is important to assessing a patient s overall health status. 5. Your textbook points out that an estimated 300,000 people die yearly from obesity related diseases. Outline some of these obesity related diseases and what costs might be associated with each disease. What is your role as an RD in helping to prevent obesity related diseases overall? 6. In Highlight 8, the eating disorders anorexia nervosa, bulimia nervosa, and binge eating disorder are discussed. As indicated by this Highlight, it should be clear that these are complex disorders, and while there are some basic theories as to the rationale for the behaviour, there is still much to learn regarding the etiology, prevalence, and treatment of eating disorders. Nutrition and nutrition education will be a very important part of treating a patient with an eating disorder. If you were to work on an eating disorder team, what types of skills might you want to more fully develop and why? What types of additional skills might you want to have? What value would they bring to you as the nutrition expert, to your patient, and the team? 6

7 8-7 W H A T O T H E R R E S O U R C E S A R E AVA I L A B L E? You can look up information about government policy as well as any health condition that you are interested in learning more about. Consult the following websites to get reliable information on the following: Learn out more about overweight Canadian children and adolescents at m/ /pdf/ eng.pdf The 2006 Canadian clinical practice guidelines on the management and prevention of obesity in adults and children can be found at You can look up the caloric content of foods on the Nutrition website and follow the links to the Canadian Nutrition file You can check Health Canada s Natural Health Products Database at sc.gc.ca/dhp mps/prodnatur/index eng.php to identify the status of herbs or natural products that are promoted for weight loss (e.g., ma huang [ephedra] and phenylpropanolamine). Two Canadian organizations (listed below) promote the non diet approach to a healthy lifestyle. Since students with eating disorders often take nutrition courses, instructors should also tell students about programs for eating disorders available at the college or university or in their community. The National Eating Disorder Information Centre (NEDIC) provides information through a toll free phone number ( ) or Toronto phone number ( ), and the website ( The website includes a guide for family and friends. HUGS International offers support and programs for people seeking a lifestyle without dieting. The website provides a self profile quiz ( HUGS International, Box 102A, R.R. #3, Portage la Prairie, Manitoba R1N 3A3; Phone: ANSWER KEY FOR ALL I N S T R U C T O R S M A N UA L AC T I V I T I E S Critical Thinking Questions3 1. Answer: Direct calorimetry is most often performed in a bomb calorimeter, which measures the energy value of food. Within the bomb calorimeter (which is a sealed and vacuum closed space), foods are burned to establish the amount of heat released from the food during combustion. Heat released provides a measure of energy. This 3 Contributed by Kathleen Rourke.

8 8-8 system is used to simulate the body as is burns foodstuffs for energy. Direct calorimetry can also be performed on humans while they are enclosed in a special room sized device that measures the heat released by the body into the environment. Indirect calorimetry measures the oxygen consumed by living beings. This can be measured by a metabolic cart or similar apparatus. Since oxygen is required for aerobic metabolism, the amount consumed can yield an accurate approximation of the person s energy expenditure. The thermic effect of food is the measure of energy needed to process food in the body. Several activities such as increased use of digestive muscles, digestive secretions, and active transport are required for the processing of food. It is estimated that 10 percent of energy intake is devoted to the thermic effect of food. In measuring the energy released from the food we eat, it is often difficult to get an exact number as to energy released. This is partly because our bodies are always working to digest and absorb the food we eat. That process in and of itself requires energy. While the thermic effect of food is not directly related to calorimetry, we must take into account that releasing energy requires energy consumption. In that regard, there is some overlap. 2. Answer: Hunger: Is the patient able to differentiate between hunger and the variety of other reasons why an individual may eat? People often eat not because they are hungry but because they are stressed, in social situations, as a response to environmental cues such as smells that remind them of positive past events, or because of boredom, to name a few reasons. It is important to help the patient to learn to differentiate between the cognitive and sensory factors that may influence their eating responses, as opposed to true hunger. Satiety: Also part of the hunger response, many patients cannot recognize when they have achieved satiety or a sense of fullness. Because the world in which we live is fast paced and visually stimulating, most individuals seldom pay attention to how their bodies are feeling as they eat. In addition, most individuals do not have a sense of normal portion sizes in a biggie sized world. Therefore, a meal that is portion controlled may leave many individuals feeling hungry just from the visual cues, even when satiety is present. Working with patients to regain their understanding of satiety may take time and significant education, as patients learn about portion sizes and begin to reconnect their brain and brain chemistry with their bodies and their GI systems. Both working with patients on their responses to hunger and understanding of their satiety can be significant steps in lifelong weight control and improvement of health status. Appropriate responses to these signals with a healthy diet and exercise can provide a patient with a lifetime of a healthy weight without dieting. 3. Answer: To calculate the BMR for Lucy and Bob, use the Harris Benedict equation that is outlined in the textbook: For men: (10 wt. in kg) + (6.25 ht. in cm) (5 age) + 5 = BMR 8

9 8-9 For women: (10 wt. in kg) + (6.25 ht. in cm) (5 age) 161 = BMR To determine weight in kilograms, divide the weight of the individual in pounds by 2.2. To determine the height of an individual in metres, divide height in inches by Multiply height in metres by 100 to obtain height in centimetres. Bob: ( ) + ( ) (5 55) + 5 = Lucy: ( ) + ( ) (5 35) 161 = For Estimating Energy Expenditure: In men: [662 (9.53 Age)] + Physical Activity [(15.91 wt. in kg) + (539.6 ht in m)] In women: [354 (6.91 x age)] + Physical Activity x [(9.36 wt in kg) + (726 ht in m)] For Bob: Physical Activity level for text chart, select Sedentary or 1.0 [662 ( )] [( ) + ( )] = For Lucy: Physical Activity level for text chart, select Active or 1.25 [354 ( )] [( ) + ( )] = Note: if the student selects a 1.12 activity level for Lucy, this would be appropriate as well. An 1.25 activity level provides an extra energy allowance for Lucy given the many family activities and job responsibilities, knowing she would probably be on the run significantly. In the exercise, students should be able to see that activity brings its benefits and that body composition can play a role in energy needs for each patient. From here, students should be thinking about body composition and suggest that Bob and Lucy begin to increase their exercise levels to increase muscle mass and decrease fat mass (even though we do not know what their fat mass is), as a means of increasing their BMR. One smart way to start, especially for Bob, who has not been exercising, would be to begin walking on a regular basis. 4. Answer: Answer will be different with regard to students BMI. Hopefully, students will be honest and realistic about their BMI as the question serves to help them understand a bit more about their own health status and what, if any, changes they might need to make when entering the health care field. Our patients seek us out as role models; therefore, students need to know what goals they may have for themselves. Overall, this question seeks to help students to understand the difference between a simple height vs. weight comparison and that of relating height and weight with body composition. As pointed out in the text, an individual who has a greater weight because of substantial muscle mass is not necessarily at greater risk for chronic illness because of the added weight. Therefore, it is important for the RD to look not only at height and weight but also at body composition. When an individual has greater muscle mass and less body fat, their morbidity and mortality decrease and their BMR

10 8-10 increases. In the past, health care providers have wrongly focused only on height and weight without understanding anything about body composition. As scientific technology has advanced, we are now capable of rapid and thorough total body assessment of each patient. Body composition measures include skinfolds, bioelectrical impedance analysis, underwater weighing, and air displacement plethysmography. Skinfold Calipers: Measuring skinfold thickness is a relatively inexpensive, non invasive means of measuring body fat. Skinfold calipers run in cost from a couple of dollars to a couple thousand dollars (approximately $3000) and can provide a reasonable estimate of an individual s total body fat, relative to weight. Calipers allow for assessment of total body fat on a large population of study subjects and can be done by the majority of individuals after a good training program. Therefore, use of skinfold calipers for body fat assessment is not restricted to a medical professional. Developing skill in assessment of body fat via the skinfold calipers is crucial in gathering reliable results. Body fat assessment is determined by three measurements on an individual: back of the arm, stomach, and hip. These measurements are put into an equation that has been tested for reliability and validity, and estimating total body fat with the skinfold calipers rated well with good technique. The problem in gathering reliable and valid total body fat results via the skinfold calipers is based on the wide variability of skill and technique between researchers/clinicians. Good technique is needed to gather the best results, as is good instrumentation. Individuals who rapidly perform skinfold assessment after training with an experienced individual report far better results than those that provide skinfold assessments on an occasional basis. In addition, instrumentation is quite variable. The gold standard for skinfold assessment is the Lange calipers, which are on the high end of cost; therefore, while a researcher/clinician may be quite experienced, inexpensive calipers may similarly affect reliability and validity of the outcome. To prevent some of this individual and instrument variability, multiple skinfold assessments are recommended. Some researchers utilize the mean of three measures or take the mean of three different researcher/clinician assessments. Weight loss programs that are focusing on overall health as well as diet and exercise can benefit from body fat assessments via the skinfold calipers because this measurement is one of a series of measures for the individual and success in not measured by body fat alone but a combination of measurements, including total body weight, body fat, and overall healthfulness of the food plan with exercise. Bioelectrical Impedance Analysis: Measuring total body fat with bioelectrical impedance is another relatively inexpensive, non invasive technique. Bioelectrical impedance measures resistance by the body to a small electrical current that is passed through the body via four electrodes. Simply, bioelectrical impedance measures the differences in current transmission through fat mass and muscle mass within the body. Muscle mass is bathed in water and electrolytes that allow the electrical current to be 10

11 8-11 readily transported through the body, while fat mass is dense and low in water/electrolyte medium to allow for swift transmission of a small electrical current. Using a technique such as bioelectrical impedance allows a researcher/clinician to quickly calculate an individual s total body fat without pain, an invasive technique, and lengthy caliper assessments and calculations. Individuals do not feel the small electrical current that passes through the body tissues and performing a bioelectrical impedance (BIA) test is relatively quick (less than five minutes). Electrode placement, while important, is much easier to establish if the assessor follows the clear diagrams as compared to the skinfold caliper technique, which requires not only skill in site choices but also in technique of lifting the skinfold for proper assessment. However, bioelectric impedance is not without problems when working toward maximum reliability and validity of measurement. Because the BIA measurement is based on current transmission through an aqueous environment, hydration of the subject is critical to its outcome. Over or underhydration can affect the measurement significantly, rendering it invalid. Therefore, patients with cardiovascular or renal issues are not always good subjects for BIA. The assessor must be well informed regarding the individual s hydration status to assure a reliable and valid measure; therefore, in obese subjects who may try to minimize fluid status and food intake prior to their assessment, body fat measurement via bioelectrical impedance may be unreliable. Underwater Weighting: Underwater weighing or hydrostatic weighing has been the gold standard for measuring body fat for many years. Only with the recent development and standardization of DEXA scanners and air displacement plethysmography has hydrostatic weighing for body fat/body composition become challenged. This is not due to any fatal flaw in the validity of the equation but from the relative ease for the subject in administering the DEXA or Bod Pod test. Measuring body fat via hydrostatic measurement is based on the premise that when the subject is fully submerged in a tank of water of a known temperature, and assuming the subject is able to expel all air from their lungs prior to submerging under water, the difference in the subject s density from that of the water density can be measured. Subjects are asked to wear a light bathing suit for the test. Their height and weight is taken prior to the subject entering the tank. Once the subject enters the hydrostatic tank, he or she is seated on a swing like chair and asked to blow all of the air out of his or her lungs prior to bending down into a fetal position under the water. Once the subject is submerged, it is crucial that the person remains still for several seconds while the researchers record the underwater measurement. Researchers indicate to the subject prior to submersion how they will notify that the measurement has been taken and it is OK to come to the surface. In performing hydrostatic measurements, researchers will generally take the mean of three measurements for each subject. The rationale is that subjects in the hydrostatic tank can take one or two measurements to become fully acquainted and comfortable with the entire procedure. To ensure the most reliable test results, the subject must be

12 8-12 able to blow the majority of the air out of their lungs prior to submerging under the water. For some subjects this can be especially difficult, particularly if the person is uncomfortable in the water. Remaining still under the water while the researcher takes the measurement can also be difficult for some individuals. Therefore, it is very important to keep subjects calm and reassure them often to optimize the results. Bod Pod: Based on the same principle as hydrostatic weighing, the Bod Pod or air displacement plethysmography has been in use for approximately 10 years. While the technique is relatively new, research has increasingly demonstrated good reliability and validity with the Bod Pod and its benefits are several when compared to hydrostatic weighing. First, subjects do not have to get into a large water tank, nor are they required to expel all the air out of their lungs prior to submerging themselves underwater and hold themselves still while they are being weighed. For subjects that are uncomfortable in water, this is a good alternative. The air displacement plethysmography system measures body composition by determining body volume and body weight. Once those two variables are determined, body density can be computed and inserted into an equation to provide percent fat measurements. Body weight is easily determined by the use of an accurate scale. Body volume is determined by applying the gas law (p1v1 = p2v2) and expansion of Boyle s Law, pv = c. The air displacement plethysmograph measures volume by monitoring changes in pressure within a closed chamber. These pressure changes are achieved by oscillating a speaker mounted between the front testing chamber and a rear reference chamber, which causes complementary pressure changes in each chamber. The pressure changes are very small and are not noticed by the individual being tested. Three measurements are performed to determine body volume. The volume of the front chamber while it is empty is the first measurement taken by the air displacement plethysmograph. The second measurement is the volume of the chamber while the subject is inside the chamber. By subtraction, the volume of the subject is determined. By combining volume with the third measurement of mass, the subject s density is determined and subsequently his or her body composition is determined. 5. Answer: There are several comorbidities associated with obesity, and the costs associated with obesity and its comorbidities continues to climb as health care costs continue to spiral out of control. Common diseases associated with obesity include cardiovascular disease, diabetes, and some cancers. Added weight can also contribute additional problems to individual s suffering from arthritis and lung disease. Because the obese condition affects every organ system, muscle, and bone of the body, the added weight puts a great strain on the body and its systems. The cardiovascular system must pump blood through miles of vessels and to the many organs, providing nutrients and oxygen. The obese person not only adds additional work effort to the system via increased mass but also compromises the system with plaque that lines the walls of the arteries, resulting in smaller vessel diameters through which the blood needs to be pumped. This also increases the workload of the heart. 12

13 8-13 The majority of diabetes in the country is a result of obesity. With increasing weight and poor dietary habits, the body becomes less effective or efficient in responding to and eventually producing insulin to process glucose. While the severity of diabetes ranges from individuals that can manage the condition with diet alone to those that must inject insulin to survive, it is clear that weight and diet play a major role in the development of type 2 diabetes, along with family history. The role of weight gain in cancer development is still being researched; however, we do know that fat tissue is a source of estrogen, more specifically in women. High estrogen is associated with some cancers, but as your textbook indicates, more work is still being performed to understand the exact relationship between obesity and cancer. One other factor to consider might be the types of diet that lead to weight gain and whether an individual is sedentary or not. Given the multiplicity of factors that may be a part of this picture, certainly there is much to study. In the case of any chronic disease such as cardiovascular disease or diabetes, significant long term health care is required with significant use of medications to control the disease process. Regular visits to a health care provider, regular use of multiple medications, regular laboratory studies, and if necessary, hospitalizations add up to expensive health care costs. Compliance among many patients is generally good at best, often leaving the ownership of care up to the health care provider instead of the patient. Because our nation s health care system is really a sick care system, most patients are not highly motivated to take ownership for their health status, and health promotion programs that support nutrition education and counselling often are paid for by the patient. If the patient is unable to pay, most often he or she will not participate. The role of RDs is to advance the role of health promotion and prevention as much as they are able through early assessment of patients and their family members that may be at risk for obesity and its comorbidities. RDs can collaborate with other health care providers and practitioners to provide health promotion services for their patients in the health care setting and the community. If the RD is too strict or unrealistic about a food plan, a patient will not be able to follow it and the RD has set the patient up for failure. Be realistic and set small goals along the way to a large goal. Be supportive and humane to the patient. If the patient perceives the RD has not had to struggle with weight issues, the patient may not be able to relate. Be relatable. If the RD has a weight issue and is doing nothing about it, that can also present a barrier for the patient. 6. Answer: Highlight 8 does a good job of providing an overview of eating disorders, yet students require an understanding of the complexity of these disorders, the resistance of each to treatment, and the need for treatment to be taken on as a team approach. Therefore, with this question, we are looking for students to think more deeply about the many different rationales why eating disorders exist (for the nutrition profession to use in prevention and treatment), reminding students to think about the need for strong assessment skills and the ability to work well in teams.

14 8-14 As the nutrition expert on an eating disorder team, it is very important to fully understand the many rationales for the development of eating disorders. While it is believed that society sets up unrealistic expectations for young girls and women through its display of very thin and flawless models, family dynamics also play a role in the development of some disorders such as anorexia nervosa. In striving for perfection, some individuals are striving for attention as well and the interplay between personal dynamics, family dynamics, and societal marketing can be very complex. The RD will need to understand and appreciate the numerous issues at play and work closely with a psychologist or psychiatrist who can determine the primary and secondary issues for each particular patient. Once the primary and secondary rationale for each patient with an eating disorder are determined, the RD can then assist the patient more appropriately in setting up the best approach to a nutrition program. For example, if the individual is driven by family issues and secondarily by societal expectations, understanding the food dynamics around the family will help to maximize the nutrition program that is set up. It will be important to have a thorough understanding of the many factors that can influence the onset of the different types of eating disorders and that there is interplay between them. While patients might be able to be grouped together, it is best to take each patient as an independent case and understand the psychological, social, and nutritional factors for that person uniquely. Do not make the mistake that this is a women s only illness. Boys and men also suffer from eating disorders and are easily overlooked given their frequent association with women and girls only. Understanding that each individual brings his or her own unique characteristics to this illness assists the RD in better targeting treatments, and understanding that the disease does not differentiate between genders assists the RD in not overlooking a patient that may be in much need of nutrition counselling and care. Working with each patient to accept his or her own unique features takes time and teamwork. It cannot be overemphasized enough that working on an eating disorder team is very much teamwork with plenty of communication. Individuals with eating disorders can be quite manipulative; therefore, to optimize the patient s outcome, there is no room for stars on the team, just team members who communicate well among each other and appreciate what each other member brings to the team and the welfare of the patient. Generally, the team consists of a physician, psychologists or psychiatrists, RD, RN, exercise physiologists or PT, social worker, and perhaps an OT. Treatment can be slow with many relapses. There are many types of treatment approaches, given eating disorders appear to be so resistant to treatment, particularly the more severe the client case. Family involvement is important but requires skilled practitioners and thoughtful approaches. Working in teams is not always an easy task and with this particular client population it is essential that the team work together. Dietitians who are not particularly keen on working in teams should seek an alternative career route. So too should the RD understand the fatigue that can be involved in working with an eating disordered patient. Much patience is required to work in this patient population as well as skill in working with very emotionally labile individuals. A significant amount of counselling 14

15 8-15 ability is needed to be successful as well as a strong emotional constitution within the RD. The nutrition professional working on an eating disorder team does require several well developed skills and some advanced skills. With respect to the Female Athlete Triad, the RD must have acute skills for assessing an individual s body image, self esteem, and self report about exercise and diet. These are combined with physical assessments of body fat (body composition), weight, and height. A full panel of blood work should be requested by the collaborating physician, plus a DEXA scan for bone density. In looking at the blood work, the RD would assess calcium and potassium and sodium status and determine whether the client s hormones have been compromised from lack of fatty acids. Physically, the RD should be able to distinguish the differences in skin tone, hair and nail bed strength, etc. that would give the RD some feedback on the patient s nutritional intake and vitamin and mineral quality of the diet. Such information also informs the RD about the patient s hydration status. Given that eating disordered patients can be physiologically labile, the RD must be able to carefully assess patients at all levels and respond to their assessments quickly. The nutrition professional and all other members of the health care team must work in concert on behalf of the patient. Nutrition education not only for team members, to communicate what you are doing with patients, but also to the community and to coaches can be a vital part of helping to prevent eating disorders. However, providing nutrition education to some segments of society is not always that easy. Some sports, such as ice skating and gymnastics as well as wrestling, have years of history as to how nutrition programs were handed down to the athletes. While tradition is changing slowly, within each community change is a process of communication and trust. Sharing information and working together with the coaches to optimize their bottom line may take a message much farther than trying to change the whole program. Every chance the RD has to work with coaches toward educating and counselling athletes on nutrition increases the likelihood that athletes will receive healthful nutrition information. So too does this advice hold true for young school children. Nutrition professionals who get involved in school education programs optimize the chances that young girls and boys will learn about good nutrition and learn to accept their bodies. Therefore, the role of the RD does not stop in the clinics but extends well beyond. Worksheet Answer Key Worksheet 8 1: Energy Calculation = 8.4 kcal/min; = 126 total kcal spent per day; = 378 kcal spent per week = 6.2 kcal/min; = 744 total kcal spent per week = 7.3 kcal/min; = total kcal spent per day; = kcal spent per week

16 = 8.7 kcal/min; = 174 total kcal spent per day; = 1,218 kcal spent per week = 5.7 kcal/min; = 85.5 total kcal spent Worksheet 8 2: Body Mass Index (BMI): Reality vs. Myths 1. BMI = 24.3; healthy 4. BMI = 25.7; overweight 2. BMI = 28.2; overweight 5. BMI = 34.4; obese 3. BMI = 27.9; overweight Worksheet 8 3: Chapter 8 Crossword Puzzle 1. stress eating 4. central obesity 7. frame size 2. underweight 5. satiety 8. appetite 3. satiation 6. overweight 9. hunger 10. overfat Worksheet 8 4: Energy In and Energy Out (Internet Exercise) 1. False 3. False 5. True 2. d True

17 8-17 W O R K S H E E T AC T I V I T I E S Worksheet 8 1: Energy Calculation Using Table 8 2 in your textbook, calculate the amount of expended kcalories for each of the identified activities. Show each step of the calculation process. 1. Male patient weighing 175 pounds who weight lifts (vigorous effort) for 15 minutes three times a week. 2. Female patient weighing 138 pounds who plays golf once a week carrying her clubs and averages 120 minutes on the golf course. 3. Male patient weighing 75 pounds who plays soccer (vigorously) three times a week for 45 minutes at each attempt. 4. Female patient weighing 115 pounds who rides a bicycle (averaging 31 km/h) each day for 20 minutes. 5. Male patient weighing 189 pounds who is wheeling himself in a wheelchair for 15 minutes.

18 8-18 Worksheet 8 2: Body Mass Index (BMI): Reality vs. Myths Reality Myth If your BMI > 25, you are considered to be overweight. Only a high BMI affects health status. If your BMI > 30 you are considered to be clinically obese. You only have to worry when your BMI > 40 because only then you are considered to be morbidly obese. If your BMI is within a healthy range, then you are considered to be at the right weight for your given height. If your BMI is within a healthy range ( ), then you don t have to worry about any health problems. If your BMI < 18.5, you are considered to be underweight. Only a low BMI affects health status. Using the following data, calculate the patient s BMI and determine whether they are considered to be underweight, healthy, overweight or obese foot 8 inches, 160 pounds BMI = ; patient is considered to be foot 2 inches, 220 pounds BMI = ; patient is considered to be foot 11 inches, 138 pounds BMI = ; patient is considered to be foot 4 inches, 150 pounds BMI = ; patient is considered to be foot 10 inches, 240 pounds BMI = ; patient is considered to be. 18

19 8-19 Worksheet 8 3: Chapter 8 Crossword Puzzle Across Down 4. Excess fat around the trunk of the body 5. The feeling of satisfaction and fullness that food brings 7. The size of a person s bones and musculature 9. The physiological need to eat, experienced as a drive to obtain food 10. An excess of body fat 1. Eating in response to arousal 2. Body weight below some standard of acceptable weight that is usually defined in relation to height 3. The feeling of satisfaction that occurs during a meal and halts eating 6. Body weight above some standard of acceptable weight that is usually defined in relation to height 8. The psychological desire to eat or interest in food

20 8-20 Worksheet 8 4: Energy In and Energy Out (Internet Exercise) Go to the following website to answer questions 1 5: weight basics/balance.htm. Do not close the window after answering these questions. 1. A female aged 16 who is sedentary should consume 1000 calories per day. a. True b. False 2. Which of the following statements is accurate concerning the estimation of calorie requirements for gender and age group for the three designated levels of physical activity? a. A sedentary lifestyle only includes sitting activities. b. An active lifestyle includes walking 2 miles per day at 2 miles per hour. c. Both older age adults and adolescents require fewer calories, relative to younger age adults and adolescents. d. The levels are based on information obtained from the IOM Dietary Reference Intakes report. 3. To reduce energy in by 150 calories (kcal) for a 150 pound person, one should eat a 6 ounce can of tuna that is packed in light oil. a. True b. False 4. Eating 150 extra calories (kcal) per day can lead to a weight gain of 10 pounds in one year s time. a. True b. False 5. To increase energy out by 150 calories (kcal), one can dance for 30 minutes. a. True b. False 20

21 8-21 Handout 8 1: How To Determine Body Weight Based on BMI A person whose BMI reflects an unacceptable health risk can choose a desired BMI and then calculate an appropriate body weight. For example, a woman who is 5 feet 5 inches (1.65 metres) tall and weighs 180 pounds (82 kilograms) has a BMI of 30: BMI = 82 kg 1.65 m2 = 30 or BMI = 180 lb 703 = in2 A reasonable target for most overweight people is a BMI 2 units below their current one. To determine a desired goal weight based on a BMI of 28, for example, the woman could divide the desired BMI by the factor appropriate for her height from the table below: desired BMI factor = goal weight = 169 lb To reach a BMI of 28, this woman would need to lose 11 pounds. Such a calculation can help a person to determine realistic weight goals using health risk as a guide. Alternatively, a person could search the table on the inside back cover for the weight that corresponds to his or her height and the desired BMI. Height Factor Height Factor Height Factor 4 7 (1.40 m) (1.60 m) (1.80 m) (1.42 m) (1.63 m) (1.83 m) (1.45 m) (1.65 m) (1.85 m) (1.47 m) (1.68 m) (1.88 m) (1.50 m) (1.70 m) (1.90 m) (1.52 m) (1.73 m) (1.93 m) (1.55 m) (1.75 m) (1.96 m) (1.57 m) (1.78 m) (1.98 m) 0.116