Energy Balance and Body Composition PDF

Chapter 7 Dr. Zainab Zueter  Energy Imbalance ✓Energy Balance Basics: o People constantly use energy and eat periodically to refuel. o Ideally, energy intake should match energy expenditure. o Excess energy is stored as fat, which is used between meals. o Even healthy-weight adults have si...

Chapter 7 Dr. Zainab Zueter  Energy Imbalance ✓Energy Balance Basics: o People constantly use energy and eat periodically to refuel. o Ideally, energy intake should match energy expenditure. o Excess energy is stored as fat, which is used between meals. o Even healthy-weight adults have significant fat energy reserves (50,000 to 200,000 calories). ✓Daily Energy Balance: o Body fat changes depend on daily energy balance (energy in vs. energy out). o Weight maintenance occurs when the energy in equals energy out. o Weight changes when this balance shifts.  Energy Imbalance ✓The 3500 Kcalorie Rule: o Traditionally, 3500 kcalories excess = 1 pound of fat gained (and vice versa for loss). o Many diets recommend reducing intake by 500 kcalories/day for 1 pound/week loss. o This rule has limitations and doesn't account for individual differences. ✓Limitations of the 3500 Kcalorie Rule: o Weight loss slows down over time as the body adapts. o Calorie deficits affect men and women differently. o Obese and lean individuals have different calorie deficit needs for weight loss. Energy Imbalance: Fat Cell Enlargement Copyright © 2017 Cengage Learning. All Rights Reserved.  Energy Imbalance ✓ Composition of Weight Changes: o Weight changes include fat, fluid, and lean tissue shifts o Rapid changes often include water retention/loss(60% of adult body weight is water). o Long-term weight changes: about 75% fat and 25% lean tissue; during starvation, fat and lean losses are equal. ✓ Energy Balance Equation: o The simple energy in vs. energy out equation doesn't fully explain obesity's complexities. o Metabolic changes play a significant role in weight management. ✓ Review: o Energy balance occurs when energy consumed equals energy expended, resulting in stable weight. o Weight gain occurs when energy intake exceeds expenditure. o Weight loss occurs when energy expenditure exceeds intake.  Energy Imbalance ✓ Composition of Weight Changes: o Weight changes include fat, fluid, and lean tissue shifts o Rapid changes often include water retention/loss(60% of adult body weight is water). o Long-term weight changes: about 75% fat and 25% lean tissue; during starvation, fat and lean losses are equal. ✓ Energy Balance Equation: o The simple energy in vs. energy out equation doesn't fully explain obesity's complexities. o Metabolic changes play a significant role in weight management. ✓ Review: o Energy balance occurs when energy consumed equals energy expended, resulting in stable weight. o Weight gain occurs when energy intake exceeds expenditure. o Weight loss occurs when energy expenditure exceeds intake.  Energy in: The kCalories Foods Provide : Food Composition ✓ Foods and beverages contribute to the "energy in" component of the energy-balance equation. ✓ The energy received from food depends on its composition and the consumed quantity. ✓ A bomb calorimeter can measure the kcalories a food provides by burning the food and measuring the released heat. ✓ Burning food generates heat, carbon dioxide, and water, providing a measure of the food's energy value. ✓ The bomb calorimeter offers a direct energy measurement but overstates the physiological fuel value, which is the energy actually derived by the human body. ✓ The body's metabolism is less efficient than a calorimeter's, requiring mathematical corrections for accurate energy value tables. ✓ Energy values of foods can also be calculated based on the macronutrient content: carbohydrates, fats, proteins, and alcohol if present. ✓ Example calculation: A food with 12 grams of carbohydrates, 5 grams of fat, and 8 grams of protein provides a total of 125 kcalories (48 from carbohydrates, 45 from fat, and 32 from protein).  Energy in: The kCalories Foods Provide : Food Composition ✓Bomb Calorimeter: o Used to measure the energy content of foods. o Burns food and measures heat released. o Provides a direct measure of food's energy value. ✓Calorimeter Process: o Burning food releases heat, carbon dioxide, and water. o Similar to how body cells metabolize nutrients. o Chemical bonds break, forming CO2 and H2O. o Oxygen consumption indirectly measures the energy released. o The reactions in a bomb calorimeter and the body are similar but differ in detail. o In body: Burning food breaks chemical bonds, combining carbon and hydrogen with oxygen. o This produces carbon dioxide and water. o The oxygen consumed indirectly measures the energy released from the food. Energy in: The kCalories Foods Provide : Food Composition ✓ Physiological Fuel Value: o Bomb calorimeter overestimates energy available to the human body. o The body is less efficient than a calorimeter in extracting energy from food. o Cannot metabolize all energy-yielding nutrients completely. ✓ Energy Value Tables: o Researchers mathematically correct calorimeter measurements. o Create tables with more accurate food energy values. o Provide reasonable estimates, not precise individual energy derivation. ✓ Energy values of foods can be calculated based on their macronutrient content (carbohydrates, fats, proteins, and alcohol if present). ✓ Example: A food with 12 grams of carbohydrates, 5 grams of fat, and 8 grams of protein provides a total of 125 kcalories (48 from carbohydrates, 45 from fat, and 32 from protein).  Energy in: The kCalories Foods Provide :Food intake ✓ Appetite plays a crucial role in regulating food intake, influencing when and how much a person eats. ✓ The decision to eat or not eat isn't solely based on hunger. ✓ The body uses various signals to determine when to start and stop eating. ✓ These signals can be influenced by environmental factors and genetic Appetite: the integrated response to the sight, smell, predispositions. thought, or taste of food that initiates or delays eating. Hunger: the painful sensation caused by a lack of food that initiates food-seeking behavior Food intake : Hunger o People eat for various reasons, primarily hunger, which is the physiological response to food needs. o Hunger is triggered by nerve signals and chemical messengers in the brain, mainly the hypothalamus. o It can be influenced by nutrients in the bloodstream, previous meal, meal size/composition, eating patterns, climate, physical activity, hormones, and illness. o Hunger determines what to eat, when to eat, and how much to eat. o The stomach typically prompts eating every 4 hours after a meal when it is empty or nearly empty. Hunger: the painful sensation caused by a lack of food that initiates food-seeking behavior  Food intake : Satiation, Satiety ✓ Satiation o Satiation occurs during a meal as food enters the GI tract, as hunger diminishes, making the person feel full. o Triggered by stomach stretching, hormones like cholecystokinin are released, signaling to stop eating. ✓ Satiety o After a meal, satiety continues to suppress hunger, allowing delays in the next eating episode. o Satiation tells us to stop eating, while satiety reminds us not to start eating again. o Satiety: Continues after a meal, suppressing hunger, Prevents eating again for a while satiety : satiation : the feeling of fullness and the feeling of satisfaction and satisfaction that occurs after a meal and inhibits eating until fullness that occurs during a meal and halts eating. Satiation the next meal. Satiety determines how much time passes determines how much food is consumed during a meal. between meals.  Food intake: Overriding Hunger and Satiety ✓ Overriding Hunger and Satiety Eating can be triggered by signals unrelated to hunger, including emotional states like boredom or anxiety. Food cravings can lead to eating in response to various stressors, both negative (e.g., grief) and positive (e.g., celebration). Chronic stress relief through food can contribute to overeating and subsequent weight gain. External cues—such as time of day, food availability, sight, and taste—can stimulate eating regardless of hunger. Environmental factors like large portion sizes, favorite foods, and food variety can increase energy intake. Cognitive factors—such as perceptions, memories, and social interactions—can lead to weight gain, with overweight or obese individuals particularly susceptible to external hunger triggers. Eating can be suppressed by signals independent of satiety, as seen in individuals with eating disorders like anorexia nervosa, who may discipline themselves to ignore hunger. Some individuals may also refrain from eating during stressful situations, leading to difficulty eating under emotional strain.  Food intake: Sustaining Satiation and Satiety ❖Factors Influencing Satiation and Satiety: o The nutrient composition of a meal affects how satiating and sustaining it is. o Protein is the most satiating macronutrient, while sugary drinks can increase appetite. o Foods low in energy density (e.g., high-fiber foods) are more satiating and help control hunger. o Fat has a weak effect on satiation but a strong effect on satiety, High-fat foods can lead to overconsumption due to their energy density and flavors. ❖Portion Size and Satiety: 1. Directly correlated 2. Large portions of low-fat, high-fiber, low-energy-density foods can be satisfying  Food intake: Sustaining Satiation and Satiety ✓ Nutrient composition of meals influences satiation and satiety ✓ Protein is the most satiating among energy-yielding nutrients ✓ Protein deficiency can lead to persistent hunger ✓ Protein consumption (e.g., milk) provides satiety and reduces subsequent energy intake ✓ Fructose in sugary drinks may stimulate appetite and increase food intake ✓ Low energy density foods are more satiating ✓ High-fiber foods promote satiation by filling the stomach and delaying nutrient absorption ✓ Example: Large salad as a first course reduces subsequent meal intake  Food intake: Sustaining Satiation and Satiety ✓ Fat has weak satiation effects, potentially leading to passive overconsumption ✓ Fat has a weak effect on satiation(High-fat foods can lead to overconsumption due to their energy density and flavors) but a strong effect on satiety, (Intestinal fat triggers cholecystokinin release, signaling satiety and inhibiting food intake) ✓ Portion Size and Satiety: Direct correlation between portion size and satiety ✓ Portion Size and Satiety: Large portions of low-fat, high-fiber, low-energy-density foods can be satisfying  Food intake: Message Central—The Hypothalamus ✓Eating behavior is a complex process influenced by genetic, psychological, social, metabolic, and physiological factors. ✓The hypothalamus serves as the control center for eating, integrating signals related to energy intake, expenditure, and storage from various brain regions, the mouth, GI tract, and liver. ✓Messages from the hypothalamus affect: Satiation messages: which helps control meal size. Satiety messages: determine meal frequency  Food intake: Message Central—The Hypothalamus ✓Gastrointestinal Hormones: o Numerous hormones influence appetite control and energy balance o Understanding their action may lead to potential anti-obesity treatments ✓ Brain Chemicals: o Present an additional challenge in understanding eating behavior o Example: Neuropeptide Y 1. Causes carbohydrate cravings 2. Initiates eating 3. Decreases energy expenditure 4. Increases fat storage 5. Promotes positive energy balance and weight gain Energy Out: The kCalories the Body Expends Components of Energy Expenditure 1. Basal Metabolism 2. Physical activity 3. Thermic effect of Food 4. adaptive Thermogenesis  Energy Out: The kCalories the Body Expends Heat is released when the body breaks down carbohydrates, fats, or proteins for energy and when that energy is utilized for work. The process of heat generation is termed thermogenesis, which can be measured to assess energy expenditure. Total energy expenditure is categorized into three main types of thermogenesis: 1. Energy expended for basal metabolism: the energy required to maintain basic bodily functions at rest. 2. Energy expended for physical activity: the energy used during any form of movement or exercise. 3. Energy expended for food consumption: the energy required for digestion, absorption, and metabolism of food. A fourth category, which may also be considered, is: Energy expended for adaptation: energy used by the body to adapt to changes in the environment or internal conditions.  Components of Energy Expenditure 1-Basal Metabolism ✓ Basal metabolism accounts for about two-thirds of daily energy expenditure, supporting basic life functions and Metabolic activities. ✓ Metabolic activities include: 1. Lung function (inhaling/exhaling). 2. Bone marrow producing new red blood cells. 3. Heart beating approximately 100,000 times daily. 4. Kidneys filtering waste. ✓ The basal metabolic rate (BMR) is the rate of energy expenditure for these life-sustaining activities. ✓ BMR varies between individuals and can change based on circumstances or physical conditions. ✓ BMR is lowest during undisturbed sleep; it is typically measured while a person is awake, lying still, in a comfortable environment, after restful sleep and a 12 to 14-hour fast. ✓ The resting metabolic rate (RMR) is slightly higher than BMR due to less stringent criteria regarding recent food intake and activity levels. ✓ In cases where direct measurement is not possible, equations can provide reasonably accurate estimates of BMR.  Components of Energy Expenditure 1-Basal Metabolism Generally, greater body weight correlates with higher total energy expenditure, though energy expenditure per pound may be lower. Example: An adult may have a BMR of 1500 kcal/day, while an infant's BMR may be 500 kcal/day, but the infant's BMR is twice as fast relative to their body weight. Lean tissue has a higher metabolic rate compared to body fat, impacting BMR comparisons between different body types. ✓ Factors influencing BMR: BMR tends to be highest in growing individuals (children, adolescents, pregnant women) and those with higher lean body mass (physically fit individuals and males). Regular participation in endurance and strength-training can help increase BMR by maximizing lean body mass. BMR is elevated in individuals with fever, stress, or highly active thyroid glands. BMR decreases with loss of lean body mass, fasting, and malnutrition. Components of Energy Expenditure 1-Basal Metabolism Components of Energy Expenditure 1-Basal Metabolism Components of Energy Expenditure 1-Basal Metabolism Definitions ✓ Basal metabolic rate : the rate of energy use for metabolism under specified conditions: after a 12-hour fast and restful sleep, without any physical activity or emotional excitement, and in a comfortable setting. It is usually expressed as kcalories per kilogram of body weight per hour. ✓ Resting metabolic rate : similar to the basal metabolic rate (BMR), a measure of energy use for a person at rest in a comfortable setting, but with less stringent criteria for recent food intake and physical activity. Consequently, the RMR is slightly higher than the BMR. ✓ lean body mass: the body minus its fat.  Components of Energy Expenditure 2-Physical activity ✓ Physical Activity: Voluntary movement of the skeletal muscles and support systems ✓ It is the most variable and changeable component of energy expenditure, significantly influencing both weight gain and loss. ✓ Energy Needs During Physical Activity: 1. Muscles require extra energy to move 2. Heart and lungs need extra energy to deliver nutrients, oxygen, and dispose of wastes The Energy required for any activity depends on three main factors: 1. Muscle mass: More muscle mass leads to higher energy expenditure. 2. Body weight: Heavier body parts require more energy to move. 3. Activity type: Different activities have varying energy requirements. Factors influencing energy expenditure during physical activity include: 1. Duration: Longer activities expend more kcalories. 2. Frequency: More frequent activities increase total energy expenditure. 3. Intensity: Higher-intensity activities burn more calories.  Components of Energy Expenditure 2-Physical activity How Many Kilocalories Do You Need? The most accurate way to determine your energy needs: Calculate your BMR. BMR = (weight in pounds / 2.2) x 24 Factor in your activity level. No activity: multiply BMR by 1.2 Moderate activity: multiply BMR by 1.5 Intense activity: multiply BMR by 1.75 Energy Costs of Selected Activities © 2016 Pearson Education, Inc.  Components of Energy Expenditure 3- Thermic effect of Food Thermic effect of food (TeF): an estimation of the energy required to process food (digest, absorb, transport, metabolize, and store ingested nutrients); also called the specific dynamic effect (SDE) of food or the specific dynamic activity (SDA) of food. The sum of the TEF and any increase in the metabolic rate due to overeating is known as diet-induced thermogenesis (DIT).  Components of Energy Expenditure 3- Thermic effect of Food ✓ When a person eats, the following occurs: GI tract muscles increase their rhythmic contractions. Cells producing digestive juices become active. Some nutrients require absorption energy. ✓ This acceleration of activity requires energy and produces heat ❖ Quantifying the Thermic Effect of Food: o Proportional to the food energy intake o Typically estimated at 10% of energy intake o For a 2000 kcal intake, the thermic effect would be around 200 kcal ❖ Factors Influencing TEF: 1. Varies for different foods 2. Influenced by meal size and frequency 3. Generally higher for high-protein foods than high-fat foods 4. Higher for a meal eaten all at once rather than spread out For most energy expenditure estimations, TEF can be considered negligible (can be ignored) due to its minor contribution relative to overall energy intake and output estimation errors.  Components of Energy Expenditure 4- Adaptive Thermogenesis ✓Adaptive Thermogenesis: Additional energy expended when the body is challenged by dramatic changes Occurs during: Physical conditioning Exposure to extreme cold Overfeeding Starvation Trauma Other types of stress ✓ Adaptation Process: The body has extra work to do to build tissues, produce enzymes, and hormones necessary to cope with the demand ✓ Significance of Adaptive Thermogenesis: This energy expenditure can make a considerable difference in the total energy expended, especially in certain circumstances (e.g., burn victims) ✓ This component is typically not included when estimating energy needs for most healthy individuals due to its variability and individual specificity.  Estimating Energy Requirements ✓ Estimating Energy Requirements: DRI Committee developed equations based on research measuring total daily energy expenditure Key factors influencing Basal Metabolic Rate (BMR) and energy expenditure include: 1. Gender: o Women generally have lower BMR than men due to less lean body mass o Separate energy equations for men and women 2. Growth: o BMR is higher in people who are growing (e.g., pregnant/lactating women, infants, children, adolescents) o Separate energy equations for these population groups 3. Age: o BMR declines during adulthood due to the reduction of lean body mass and hormonal changes. o Physical activity typically decreases with age, contributing to a 5% reduction in energy expenditure per decade. o Ongoing physical activity can mitigate some declines in BMR.  Estimating Energy Requirements 4. Physical Activity: o Energy equations include a physical activity factor for various levels of intensity for each gender 5. Body Composition and Body Size: o BMR is higher in taller individuals due to greater surface area. o BMR is higher in individuals with greater body weight o Energy equations include factors for height and weight ✓ Energy needs vary between individuals based on gender, growth, age, physical activity, and body size and composition. ✓ Even similar individuals can have different energy requirements due to genetic factors. Estimating Energy Requirements  Body Weight and Body Composition ✓ Estimating Energy Requirements: DRI Committee developed equations based on research measuring total daily energy expenditure Key factors influencing Basal Metabolic Rate (BMR) and energy expenditure include: 1. Gender: o Women generally have lower BMR than men due to less lean body mass o Separate energy equations for men and women 2. Growth: o BMR is higher in people who are growing (e.g., pregnant/lactating women, infants, children, adolescents) o Separate energy equations for these population groups 3. Age: o BMR declines during adulthood due to the reduction of lean body mass and hormonal changes. o Physical activity typically decreases with age, contributing to a 5% reduction in energy expenditure per decade. o Ongoing physical activity can mitigate some declines in BMR.  Body Weight and Body Composition Distinction between Body Weight and Body Composition: Body Weight: The total mass of a person's body, often used to assess health status. Body Composition: Refers to the proportion of fat and lean tissues (muscles, organs, bones, and water) in the body. Example: A 5-foot-10-inch individual weighing 150 pounds may have about 30 pounds of fat, with the remaining weight comprised of water and lean tissues. Direct measurement of body composition is not feasible in living humans; researchers use indirect assessments based on the following equation: Body Weight = Fat + Lean Tissue (including water). ❖Limitations of Body Weight Measurements: Weight alone does not indicate changes in body composition; gains or losses in weight do not reflect fat vs. lean tissue changes. Many people rely on weight to evaluate their “fatness,” which can be misleading.  Defining Healthy Body Weight: Determining the appropriate weight for one's Body Weight and Body height can be complex ❖ The Criterion of Fashion: Composition o Society often sets unrealistic ideals for body weight, especially for women o Media influence leads to body image issues and unhealthy behaviors o Fashion standards of "ideal" are subjective and may not align with health ❖ The Criterion of Health: o Obesity is a major risk factor for serious diseases like heart disease, diabetes, and cancer o The goal should be to have enough fat to meet basic needs but not so much to increase health risks ❖ Body Mass Index (BMI): o Measure of relative weight for height: BMI = weight (kg) / height (m)² ❖ Limitations of BMI: o BMI does not directly reflect body composition o Muscular athletes may be classified as overweight by BMI o BMI guidelines may not be appropriate for all ethnic/racial groups  Body Weight and Body Composition Body mass index (BMI) Weight in kg ÷ (height in m)2 OR Weight in lb ÷ (height in inches)2 × 703 Healthy weight = BMI 18.5 to 24.9 Underweight = BMI 35 inches (88 cm) men: >40 inches (102 cm) at high risk. Ideally, waist circumference should be less than half of a person's height. The waist-to-height ratio is also useful for assessing disease risk. The waist-to-hip ratio is another measure, but waist circumference alone is preferred in clinical settings.  Body Fat and its Distribution Other Measures of Body Composition: Healthcare professionals often use BMI and waist circumference due to ease and cost-effectiveness, providing valuable insights into health risks. More precise body composition measurement techniques include: Total body water analysis Near-infrared spectrophotometry Ultrasound Computed Tomography (CT) Magnetic Resonance Imaging (MRI) Each method has advantages and disadvantages regarding cost, technical complexity, and precision. Review: BMI indicates disease risks but does not assess body composition. Ideal body fat varies, but excess fat (>22% men, >27% women) may pose health risks, rising slightly with age. Central obesity, assessed by waist circumference, indicates excess abdominal fat and is linked to chronic diseases. Body Fat and its Distribution Body Fat and its Distribution  Health risks associated with Body Weight and Body Fat Relationship Between Body Weight and Health: Higher BMI and waist circumference are correlated with increased disease risk and reduced life expectancy. People with a BMI of 18.5 to 24.9 have fewer weight-related health risks; risks increase outside this range (both too low and too high body fat impair health). A J- or U-shaped curve suggests that both extreme underweight and obesity increase early mortality risks.  Health risks associated with Body Weight and Body Fat ✓ Health Risks of Underweight: Underweight can be due to malnutrition, smoking, substance abuse, or illnesses. Underweight individuals, especially older adults, may struggle to preserve lean tissue during illnesses. Health risks include menstrual irregularities, infertility, and poor pregnancy outcomes. Increased risk of osteoporosis and bone fractures ✓ Health Risks of Overweight and Obesity: Obesity is classified as a disease with various associated health risks, including: Diabetes Hypertension Cardiovascular disease Sleep apnea Osteoarthritis Certain cancers Gallbladder and kidney diseases Complications during pregnancy and surgery Obesity-related illnesses cost the U.S. $147 billion annually.  Health risks associated with Body Weight and Body Fat ✓ Cardiovascular Disease: A strong correlation exists between obesity and cardiovascular disease risk. Central obesity significantly raises heart attack and stroke risks. Weight loss can reverse atherosclerosis and improve cardiovascular health. ✓ Type 2 Diabetes: The incidence of type 2 diabetes has risen alongside obesity rates. Obese individuals are three times more likely to develop type 2 diabetes. Central body fat is linked to insulin resistance; weight gain increases diabetes risk. Gaining more than 4.5 kilograms after age 18 doubles the risk of developing diabetes, even in individuals with average weight. Conversely, weight loss can effectively improve glucose tolerance and insulin resistance, benefiting overall health.  Health risks associated with Body Weight and Body Fat ✓Inflammation and the Metabolic Syndrome Chronic inflammation is commonly associated with obesity and contributes to various chronic diseases. As body fat increases, lipids first fill adipose tissue before migrating to other tissues (e.g., muscles, liver). Fat accumulation in the liver (fatty liver) is a significant factor in obesity-related diseases. Accumulated fat, particularly in the abdominal area, alters metabolism, leading to: Insulin resistance and elevated blood glucose levels. Low HDL cholesterol levels. High triglycerides. High blood pressure. These symptoms collectively form the metabolic syndrome, which heightens the risks for diabetes, hypertension, and atherosclerosis.  Health risks associated with Body Weight and Body Fat ✓Inflammation and the Metabolic Syndrome Although normal adipose tissue has few immune cells, weight gain increases their number and inflammation role. Elevated blood lipids, from either obesity or a high-fat diet, further promote inflammation. Chronic inflammation is linked to obesity and the progression of metabolic syndrome and related diseases. Even healthy young individuals show a positive correlation between body fat and chronic inflammation. Weight loss is effective in: Improving insulin resistance. Decreasing the number of immune cells in adipose tissue and Modifying gene expression to reduce inflammation.  Health risks associated with Body Weight and Body Fat Cancer ❖The risk of certain cancers increases with higher body weight and weight gain, though the exact mechanisms are not fully understood. ❖One potential explanation is that obese individuals have elevated hormone levels that may promote cancer development. For example, adipose tissue is the primary site for estrogen synthesis in women; thus, obese women often have higher estrogen levels. Elevated estrogen is linked to cancers of the female reproductive system, which account for approximately half of all cancers in women. ❖Another potential explanation is that chronic inflammation associated with obesity is a risk factor for several types of cancer. ❖The chronic inflammation that accompanies obesity may be a contributing factor linking obesity to increased cancer risk, in addition to the hormonal effects. Nutrition in Practice: Eating Disorders Anorexia nervosa Bulimia nervosa  Nutrition in Practice: Eating Disorders (Anorexia Nervosa) Anorexia Nervosa: an eating disorder characterized by a refusal to maintain a minimally normal body weight and a distortion in perception of body shape and weight. Case Study: Julie, 18 years old, is 5'6" tall and weighs 104 pounds (BMI < 17), exhibiting signs of anorexia nervosa. Characteristics: Unaware of her undernourishment and dismisses the need for treatment. Experiences amenorrhea(the absence of or cessation of menstruation.), mood swings, and chronic depression. Distorted body image; perceives herself as overweight despite being severely underweight. Engages in extreme self-discipline regarding diet and exercise, often denying hunger and limiting herself to low- calorie foods. Symptoms: Reports of exhaustion and insomnia; families express concern. Uses food restriction, excessive exercise, and sometimes laxatives to control weight. Displays a fear of weight gain, leading to a refusal to acknowledge her condition.  Nutrition in Practice: Eating Disorders (Anorexia Nervosa) Health Risks: Physical consequences include malnutrition, loss of lean tissue, weakened heart function, and organ failure. Starvation can result in multiple health issues, including impaired immune response, osteoporosis, and hormonal imbalances. Potential for infertility and complications during pregnancy. Treatment: Requires a multidisciplinary approach including physicians, therapists, and dietitians. Initial goals: stop weight loss and establish regular eating patterns. Clients may start with low caloric intake, gradually increasing as treatment progresses. Individuals classified based on malnutrition risk: low, intermediate, and high-risk clients may need varying levels of intervention.  Nutrition in Practice: Eating Disorders (Bulimia Nervosa) Bulimia Nervosa: an eating disorder characterized by repeated episodes of binge eating usually followed by self-induced vomiting, misuse of laxatives or diuretics, fasting, or excessive exercise. Case Study: Kelly, 30 years old, is a flight attendant who alternates between restrictive dieting and binge eating, followed by purging. Characteristics: Eagerly concerned about food and body image, with frequent fluctuations in weight. Experiences shame surrounding her eating behaviors and often feels inadequate. Binge Eating: Characterized by a loss of control over eating, consuming large quantities of food in secrecy, often high in calories and low in nutrition. Follows restrictive dieting periods, leading to cycles of bingeing and purging. Health Risks: Serious physical consequences include electrolyte imbalances, gastrointestinal issues, dental erosion, and potential heart failure from overuse of laxatives or emetics. May suffer from psychological issues, including depression and a risk of substance abuse.  Nutrition in Practice: Eating Disorders (Bulimia Nervosa) Treatment: Focuses on establishing regular eating patterns, discontinuing purging behaviors, and learning to maintain weight without cyclic fluctuations. Cognitive Behavioral Therapy (CBT) is often effective; a mental health professional should address underlying issues like depression and addiction. Recovery rates are reported to be favorable, with many achieving positive outcomes over several years. Shared Aspects of Eating Disorders Both anorexia and bulimia share concerns regarding body image and eating behaviors, often appearing concurrently in individuals. Treatment approaches may overlap, but each disorder has distinct characteristics requiring tailored interventions. Relapses are common, and the treatment landscape includes addressing co-occurring conditions such as depression and substance abuse, as well as the psychological aspects of eating disorders. Copyright © 2017 Cengage Learning. All Rights Reserved.