Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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  kCalorie 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  BMR  Growth  Groups with adjusted energy requirements  Age  Changes with age  Physical activity  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

Negative self-perceptions Purging Restrictive dieting Binge eating Stepped Art Fig. H8-2, p. 266

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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