Energy Balance and Body Composition Chapter 8 Whitney
Energy Balance and Body Composition Chapter 8 Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy Balance § Excess energy is stored as fat § Fat is used for energy between meals § Energy balance: energy in = energy out § A shift in balance causes weight changes § Not simply fat changes § 1 pound of fat = 3500 kcalories Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition § Direct measure of food’s energy value § Bomb calorimeter § Indirect measure of energy released § Oxygen consumed § k. Calorie calculations Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition § Hunger § Physiological response to nerve signals and chemical messengers § Hypothalamus § Influences § Satiation – stop eating § Satiety – not to start eating again Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition § Overriding hunger and satiety § Stress eating § External cues § Time of day, availability, sight, taste of food § Environmental influences § Examples § Disordered eating Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition § Sustaining satiation and satiety § Nutrient composition § Protein is most satiating § Low-energy density foods are more satiating § High-fiber foods are more satiating § High-fat foods – strong satiety signals Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy In: Food Composition § The Hypothalamus § Control center for eating § Integrates messages § Energy intake, expenditure, storage § Gastrointestinal hormones Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Energy Out § Thermogenesis § Basal metabolism § Physical activity § Food consumption § Adaptation Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Components of Energy Expenditure – Basal Metabolism § About two-thirds of energy expended in a day § Metabolic activities § All basic processes of life § Basal metabolic rate (BMR) § Variations § Weight § Lean tissue § Resting metabolic rate (RMR) Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Components of Energy Expenditure – Basal Metabolism Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Components of Energy Expenditure – Physical Activity § Voluntary movement of skeletal muscles § Most variable component of energy expenditure § Amount of energy needed § Muscle mass § Body weight § Activity § Frequency, intensity, and duration Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Components of Energy Expenditure – Thermic Effect of Food § Acceleration of GI tract functioning in response to food presence § Releases heat § Approximately 10 percent of energy intake § High-protein foods vs. high-fat foods § Meal consumption time frame Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Components of Energy Expenditure – Adaptive Thermogenesis § Adapt to dramatically changing circumstances § Examples § Extra work done by body § Amount expended is extremely variable § Not included in energy requirement calculations Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Estimating Energy Requirements § Gender § Physical activity § BMR § Growth § Groups with adjusted energy requirements § Age § Changes with age § Levels of intensity for each gender § Body composition & body size § Height § Weight Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Defining Healthy Body Weight § Ideal § Not appearance based § Perceived body image and actual body size § Damaging behaviors § Subjective § Little in common with health Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Defining Healthy Body Weight Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Defining Healthy Body Weight § Body mass index § Relative weight for height § BMI = weight (kg) height (m)2 § Health-related classifications § Healthy weight: BMI = 18. 5 to 24. 9 § Other classifications § Not a measure of body composition § Variations Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Defining Healthy Body Weight Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Defining Healthy Body Weight Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution § Important information for disease risk § How much of weight is fat? § Where is fat located? § Ideal amount of body fat depends on person § General disease risk levels § Young men: 22%; Men over 40: 25% § Young women: 32%; Women over 40: 35% Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution § Needing less body fat § Some athletes § Needing more body fat § Example groups § Fat distribution § Visceral fat § Central obesity § Subcutaneous fat Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution § Waist circumference § Indicator of fat distribution & central obesity § Women: greater than 35 inches § Men: greater than 40 inches § Waist-to-hip ratio § Other techniques for body composition § More precise measures Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Body Fat and Its Distribution Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Health Risks Associated with Body Weight & Body Fat § Body weight and fat distribution correlate with disease risk and life expectancy § Correlations are not causes § Risks associated with being underweight § Fighting against wasting diseases § Menstrual irregularities and infertility § Osteoporosis and bone fractures Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Health Risks Associated with Body Weight & Body Fat Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Health Risks Associated with Body Weight & Body Fat § Risks associated with being overweight § Obesity is a designated disease § Health risks § More likely to be disabled in later years § Costs § Money § Lives § Yo-yo dieting Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Health Risks Associated with Body Weight & Body Fat § Cardiovascular disease § Elevated blood cholesterol & hypertension § Central obesity § Diabetes – type II § Central obesity § Weight gains and body weight § Cancer § Relationship is not fully understood Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Health Risks Associated with Body Weight & Body Fat § Inflammation & metabolic syndrome § Change in body’s metabolism § Cluster of symptoms § Fat accumulation § Inflammation § Elevated blood lipids § Promote inflammation Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Highlight 8 Eating Disorders Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Eating Disorders § Three disorders § Anorexia nervosa § Bulimia nervosa § Binge eating disorder § Prevalence of various eating disorders § Causes § Multiple factors § Athletes and eating disorders Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Female Athlete Triad § Disordered eating § Unsuitable weight standards § Body composition differences § Risk factors for eating disorders in athletes § Amenorrhea § Characteristics § Osteoporosis § Stress fractures Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Female Athlete Triad Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Other Dangerous Practices of Athletes § Muscle dysmorphia § Characteristic behaviors § Similarities to others with distorted body images § Food deprivation and dehydration practices § Impair physical performance § Reduce muscle strength § Decrease anaerobic power § Reduce endurance capacity Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Anorexia Nervosa § Distorted body image § Central to diagnosis § Cannot be self-diagnosed § Malnutrition § Impacts brain function and judgment § Causes lethargy, confusion, and delirium § Denial § Levels are high among anorexics Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Anorexia Nervosa § Need for self-control § Protein-energy malnutrition (PEM) § Similar to marasmus § Impact on body § Growth ceases and normal development falters § Changes in heart size and strength § Other bodily consequences Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Anorexia Nervosa § Treatment § Multidisciplinary approach § Food and weight issues § Relationship issues § After recovery § Energy intakes and eating behaviors may not return to normal § High mortality rate among psychiatric disorders Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Anorexia Nervosa Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Bulimia Nervosa § Distinct and more prevalent than anorexia nervosa § True incidence is difficult to establish § Secretive nature § Not as physically apparent § Common background characteristics of bulimics Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Bulimia Nervosa § Binge-purge cycle § Lack of control § Consume food for emotional comfort § Cannot stop § Done in secret § Purge § Cathartic § Emetic § Shame and guilt Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Bulimia Nervosa Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Negative self-perceptions Restrictive dieting Purging Binge eating Stepped Art Fig. H 8 -2, p. 266
Bulimia Nervosa § Physical consequences of binge-purge cycle § Subclinical malnutrition § Effects § Physical effects § Tooth erosion, red eyes, calloused hands § Clinical depression and substance abuse rates are high Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Bulimia Nervosa § Treatment § Discontinuing purging and restrictive diet habits § Learn to eat three meals a day § Plus snacks § Treatment team § Length of recovery § Overlap between anorexia nervosa and bulimia nervosa Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Bulimia Nervosa Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Binge-Eating Disorder § Periodic binging § Typically no purging § Contrast with bulimia nervosa § Compare with bulimia nervosa § Feelings § Differences between obese binge eaters and obese people who do not binge § Behavioral disorder responsive to treatment Whitney & Rolfes – Understanding Nutrition, 12 th Edition
Eating Disorders in Society § Society plays central role in eating disorders § Known only in developed nations § More prevalent as wealth increases § Food becomes plentiful § Body dissatisfaction § Characteristics of disordered eating Whitney & Rolfes – Understanding Nutrition, 12 th Edition
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