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  1. 1. Chapters8 & 9 Energy Balance, Body Composition and Weight Management
  2. 2. Learning Objectives <ul><li>Explain various internal and external forces that regulate satiety, hunger, and appetite. </li></ul><ul><li>Define basal metabolism and the factors that alter basal metabolism. </li></ul><ul><li>Explain thermic effect and physical activit6y as part of overall energy usage. </li></ul><ul><li>Explain direct and indirect calorimetry. </li></ul>
  3. 3. Learning Objectives cont. <ul><li>Calculate and interpret body mass index. </li></ul><ul><li>Explain health risks of obesity and describe role of waist-to-hip ratio in risk assessment. </li></ul><ul><li>Define types of obesity and treatment implications. </li></ul><ul><li>Discuss nature and nurture in obesity development. </li></ul>
  4. 4. Learning Objectives cont. <ul><li>Determine if a weight loss program is sound or fad. </li></ul><ul><li>Outline behavior modification for weight control. </li></ul><ul><li>Discuss role of diet and physical activity for weight loss. </li></ul><ul><li>Discuss effectiveness of medical interventions in obesity treatment. </li></ul>
  5. 5. Learning Objectives <ul><li>Define underweight and describe guidelines for management of underweight. </li></ul><ul><li>Discuss the reasons weight loss is difficult to accomplish and maintain. </li></ul><ul><li>Discuss the possibilities of programs for overweight/obesity prevention. </li></ul><ul><li>Assess the attitude of yourself and society toward the overweight and obese. </li></ul>
  6. 6. Learning objectives – cont. <ul><li>Define common types of eating disorders, describe how they develop and explain impact on victim. </li></ul><ul><li>Describe treatments used on eating disorders. </li></ul><ul><li>Identify diagnostic criteria for eating disorders. </li></ul>
  7. 7. Energy Balance <ul><li>“State in which energy intake, in the form of food and /or alcohol, matches the energy expended, primarily through basal metabolism and physical activity” </li></ul><ul><li>Positive energy balance </li></ul><ul><ul><li>Energy intake > energy expended </li></ul></ul><ul><ul><li>Results in weight gain </li></ul></ul><ul><li>Negative energy balance </li></ul><ul><ul><li>Energy intake < energy expended </li></ul></ul><ul><ul><li>Results in weight loss </li></ul></ul>
  8. 8. Energy Balance (Fig. 13-1) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  9. 10. Energy In Vs. Energy Out Basal Metabolism Dietary Intake Physical Activity Thermic Effect of food
  10. 11. Basal Metabolism <ul><li>The minimum energy expended to keep a resting, awake body alive </li></ul><ul><li>~60-70% of the total energy needs </li></ul><ul><li>Includes energy needed for maintaining a heartbeat, respiration, body temperature </li></ul><ul><li>Amount of energy needed varies between individuals </li></ul>
  11. 12. Influences On Basal Metabolism <ul><li>Body surface area (weight, height) </li></ul><ul><li>Gender </li></ul><ul><li>Body temperature </li></ul><ul><li>Thyroid hormone </li></ul><ul><li>Age </li></ul><ul><li>Kcal intake </li></ul><ul><li>Pregnancy </li></ul><ul><li>Use of caffeine and tobacco </li></ul>
  12. 13. Physical Activity <ul><li>Increases energy expenditure beyond BMR </li></ul><ul><li>Varies widely among individuals </li></ul><ul><li>More activity, more energy burned </li></ul><ul><li>Lack of activity is the major cause of obesity </li></ul>
  13. 14. Thermic Effect of Food (TEF) <ul><li>Energy used to digest, absorb, and metabolize food nutrients </li></ul><ul><li>~5-10% above the total energy consumed </li></ul><ul><li>TEF is higher for CHO and protein than fat </li></ul><ul><li>Less energy is used to transfer dietary fat into adipose stores </li></ul><ul><li>Suggesting what? </li></ul>
  14. 15. Measurement of Body’s Energy Needs <ul><li>Direct calorimetry </li></ul><ul><ul><li>Measures heat output from the body using an insulated chamber </li></ul></ul><ul><ul><li>Expensive and complex </li></ul></ul><ul><li>Indirect calorimetry </li></ul><ul><ul><li>Measures the amount of oxygen a person uses </li></ul></ul><ul><ul><li>A relationship exists between the body’s use of energy and oxygen </li></ul></ul>
  15. 17. Harris-Benedict Equation <ul><li>Estimates resting energy needs </li></ul><ul><li>Considers height, weight, age, and gender </li></ul><ul><li>For men: </li></ul><ul><li>66.5 + 13.8x(kg) + 5x(cm) - 6.8x(age in yr.) </li></ul><ul><li>For women: </li></ul><ul><li>655.1 + 9.6x(kg) + 1.8x(cm) - 4.7x(age in yr.) </li></ul>
  16. 18. Sample Calculations <ul><li>Man : 21 yr., 5’10” (171 cm), 155# (70 kg) </li></ul><ul><li>66.5 + 13.8x( 70kg ) + 5x( 171cm ) - 6.8x( 21 ) = 1745 kcal/day </li></ul><ul><li>Woman : 21 yr., 5’10” (171 cm), 155# (70kg) </li></ul><ul><li>655.1 + 9.6x( 70kg ) + 1.8x( 171cm ) - 4.7x( 21 )= 1536 kcal/day </li></ul>
  17. 19. Why Do You Eat? <ul><li>Hunger </li></ul><ul><ul><li>Physiological (internal) drive to eat </li></ul></ul><ul><ul><li>Controlled by internal body </li></ul></ul><ul><li>Appetite </li></ul><ul><ul><li>Psychological (external) drive to eat </li></ul></ul><ul><ul><li>Often in the absence of hunger </li></ul></ul><ul><ul><li>e.g., seeing/smelling fresh baked chocolate chip cookies </li></ul></ul>
  18. 22. Satiety Regulator <ul><li>The hypothalamus </li></ul><ul><ul><li>When feeding cells are stimulated, they signal you to eat </li></ul></ul><ul><ul><li>When satiety cells are stimulated, they signal you to stop eating </li></ul></ul><ul><li>Sympathetic nervous system </li></ul><ul><ul><li>When activity increases, it signals you to stop eating </li></ul></ul><ul><ul><li>When activity decreases, it signals you to eat </li></ul></ul>
  19. 25. Why We Eat <ul><li>Appetite is affected by a variety of external forces </li></ul><ul><li>Combination of internal and external signals drive us to eat </li></ul><ul><li>Not a perfect system; desire to eat can be overwhelming </li></ul>
  20. 26. What is a Healthy Body Weight? <ul><li>Based on how you feel, weight history, fat distribution, family history of obesity-related disease, current health status, and lifestyle </li></ul><ul><li>Current height/weight standards only provide guides </li></ul>
  21. 27. Body Mass Index (BMI) <ul><li>The preferred weight-for-height standard </li></ul><ul><li>Calculation: </li></ul>Body wt (in kg ) OR Body wt (in lbs) x 703.1 [Ht (in m)] 2 [Ht (in inches)] 2 Health risks increase when BMI is > 25
  22. 28. Estimation of Healthy Weight For men: 106 pounds for the first 5 feet add 6 pounds per each inch over five feet A man who is 5’10” should weigh 166 lbs. For women: 100 pounds for the first 5 feet add 5 pounds per each inch over five feet A women who is 5’10” should weigh 150 lbs.
  23. 29. Obesity <ul><li>Excessive amount of body fat </li></ul><ul><ul><li>Women with > 30-35% body fat </li></ul></ul><ul><ul><li>Men with > 25% body fat </li></ul></ul><ul><li>Increased risk for health problems </li></ul><ul><li>Are usually overweight </li></ul><ul><li>Measurements using calipers </li></ul>
  24. 30. Estimation of Body Fat <ul><li>Underwater weighing (Fig. 13-5) </li></ul><ul><ul><li>Most accurate </li></ul></ul><ul><ul><li>Fat is less dense than lean tissue </li></ul></ul><ul><ul><li>Fat floats </li></ul></ul>Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  25. 31. Estimation of Body Fat <ul><li>Bioelectrical impedance </li></ul><ul><ul><li>Low-energy current to the body that measures the resistance of electrical flow </li></ul></ul><ul><ul><li>Fat is resistant to electrical flow; the more the resistance, the more body fat you have </li></ul></ul><ul><li>X-ray photon absorptiometry </li></ul><ul><ul><li>An X-ray body scan that allows for the determination of body fat </li></ul></ul><ul><li>Infrared light </li></ul><ul><ul><li>Assess the interaction of fat and protein in the arm muscle </li></ul></ul>Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  26. 32. Body Fat Distribution <ul><li>Upper-body (android) obesity--”Apple shape” </li></ul><ul><li>Associated with more heart disease, HTN, Type II Diabetes </li></ul><ul><li>Abdominal fat is released right into the liver </li></ul><ul><li>Fat affects liver’s ability to clear insulin and lipoprotein </li></ul><ul><li>Encouraged by testosterone and excessive alcohol intake </li></ul><ul><li>Defined as waist to hip ratio of >1.0 in men and >0.8 in women </li></ul>
  27. 34. Body Fat Distribution (Fig.13-9) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  28. 35. Body Fat Distribution <ul><li>Lower-body (gynecoid) obesity--”Pear shape” </li></ul><ul><li>Encouraged by estrogen and progesterone </li></ul><ul><li>After menopause, upper-body obesity appears </li></ul><ul><li>Less health risk than upper-body obesity </li></ul>
  29. 36. Overweight and Obesity <ul><li>Underweight = BMI < 18.5 </li></ul><ul><li>Healthy weight = BMI 18.5-24.9 </li></ul><ul><li>Overweight = BMI 25-29.9 </li></ul><ul><li>Obese = BMI 30-39.9 </li></ul><ul><li>Severely obese = BMI >40 </li></ul>
  30. 37. Juvenile-Onset Obesity <ul><li>Develops in infancy or childhood </li></ul><ul><li>Increase in the number of adipose cells </li></ul><ul><li>Adipose cells have long life span and need to store fat </li></ul><ul><li>Makes it difficult to loose the fat (weight loss) </li></ul>
  31. 38. Adult-Onset Obesity <ul><li>Develops in adulthood </li></ul><ul><li>Fewer (number of) adipose cells </li></ul><ul><li>These adipose cells are larger (stores excess amount of fat) </li></ul><ul><li>If weight gain continues, the number of adipose cells can increase </li></ul>
  32. 41. Causes of Obesity <ul><li>Nature debate </li></ul><ul><li>Identical twins raised apart have similar weights </li></ul><ul><li>Genetics account for ~40% of weight differences </li></ul><ul><li>Genes affect metabolic rate, fuel use, brain chemistry </li></ul><ul><li>Thrifty metabolism gene allows for more fat storage to protect against famine </li></ul>
  33. 42. Causes of Obesity <ul><li>Nurture debate </li></ul><ul><li>Environmental factors influence weight </li></ul><ul><li>Learned eating habits </li></ul><ul><li>Activity factor (or lack of) </li></ul><ul><li>Poverty and obesity </li></ul><ul><li>Female obesity is rooted in childhood obesity </li></ul><ul><li>Male obesity appears after age 30 </li></ul>
  34. 43. Nature and Nurture <ul><li>Obesity is nurture allowing nature to express itself </li></ul><ul><li>Location of fat is influenced by genetics </li></ul><ul><li>A child with no obese parents has a 10% chance of becoming obese </li></ul><ul><li>A child with 1 obese parent has a 40% chance </li></ul><ul><li>A child with 2 obese parents has a 80% chance </li></ul>
  35. 44. Nature Vs. Nurture <ul><li>Those at risk for obesity will face a lifelong struggle with weight </li></ul><ul><li>Gene does not control destiny </li></ul><ul><li>Increased physical activity, moderate intake can promote healthy weight </li></ul>
  36. 45. Set Point Theory <ul><li>Weight is closely regulated by the body </li></ul><ul><li>Genetically predetermined body weight </li></ul><ul><li>Body resists weight change </li></ul><ul><li>Leptin assists in weight regulation </li></ul><ul><li>Weight returns after weight loss </li></ul><ul><li>Reduction in energy intake results in lower metabolic rate </li></ul><ul><li>Ability to shift the set point weight </li></ul>
  37. 46. Why Diets Don’t Work <ul><li>Obesity is a chronic disease </li></ul><ul><ul><li>Treatment requires long-term lifestyle changes </li></ul></ul><ul><li>Dieters are misdirected </li></ul><ul><ul><li>More concerned about weight loss than healthy lifestyle </li></ul></ul><ul><ul><li>Unrealistic weight expectations </li></ul></ul>
  38. 47. Why Diets Don’t Work <ul><li>Body defends itself against weight loss </li></ul><ul><li>Thyroid hormone concentrations (BMR) drop during weight loss and make it more difficult to lose weight </li></ul><ul><li>Activity of lipoprotein lipase increases making it more efficient at taking up fat for storage </li></ul>
  39. 48. Why Diets Don’t Work <ul><li>Weight cycling (yo-yo dieting) </li></ul><ul><li>Typically weight loss is not maintained </li></ul><ul><li>Weight lost consists of fat and lean tissue </li></ul><ul><li>Weight gained after weight loss is primarily adipose tissue </li></ul><ul><li>Weight gained is usually more than weight lost </li></ul><ul><li>Associated with upper body fat deposition </li></ul>
  40. 49. Why Diets Don’t Work <ul><li>Weight gain in adulthood </li></ul><ul><li>Weight gain is common from ages 25-44 </li></ul><ul><li>BMR decreases with age </li></ul><ul><li>Inactive lifestyle </li></ul><ul><li>Changes in body composition </li></ul><ul><li>Fluid is usually the first weight lost </li></ul><ul><li>Loss in lean body tissue means lowering the BMR </li></ul><ul><li>Very little fat is lost during weight loss </li></ul>
  41. 50. Lifestyle Vs. Weight Loss <ul><li>Prevention of obesity is easier than curing </li></ul><ul><li>Balance energy in(take) with energy out(put) </li></ul><ul><li>Focus on improving food habits </li></ul><ul><li>Focus on increase physical activities </li></ul>
  42. 51. What It Takes To Lose a Pound <ul><li>Body fat contains 3500 kcal per pound </li></ul><ul><li>Fat storage (body fat plus supporting lean tissues) contains 2700 kcal per pound </li></ul><ul><li>Must have an energy deficit of 2700-3500 kcal to lose a pound per week </li></ul>
  43. 52. Do the Math To lose one pound, you must create a deficit of 2700-3500 kcal So to lose a pound in 1 week (7 days), try cutting back on your kcal intake and increase physical activity so that you create a deficit of 400-500 kcal per day - 500 kcal x 7 days = - 3500 kcal = 1 pound of weight loss day week in 1 week
  44. 53. Sound Weight Loss Program <ul><li>Meets nutritional needs, except for kcal </li></ul><ul><li>Slow & steady weight loss </li></ul><ul><li>Adapted to individuals’ habits and tastes </li></ul><ul><li>Contains enough kcal to minimize hunger and fatigue </li></ul><ul><li>Contains common foods </li></ul><ul><li>Fit into any social situation </li></ul><ul><li>Chang eating problems/habits </li></ul><ul><li>Improves overall health </li></ul><ul><li>See a physician before starting </li></ul>
  45. 54. Cutting Back <ul><li>Control calorie intake by being aware of kcal and fat content of foods </li></ul><ul><li>“Fat Free” does not mean “Calories Free” (or “All You Can Eat”) </li></ul><ul><li>Read food labels </li></ul><ul><li>Estimate kcal using the exchange system </li></ul><ul><li>Keep a food diary </li></ul>
  46. 55. Regular Physical Activity <ul><li>Fat use is enhanced with regular physical activity </li></ul><ul><li>Increases energy expenditure </li></ul><ul><li>Duration and regularity are important </li></ul><ul><li>Make it a part of a daily routine </li></ul>
  47. 56. Behavior Modification <ul><li>Modify problem (eating) behaviors </li></ul><ul><li>Chain-breaking </li></ul><ul><li>Stimulus control </li></ul><ul><li>Cognitive restructuring </li></ul><ul><li>Contingency management </li></ul><ul><li>Self-monitoring </li></ul>
  48. 57. Weight Maintenance <ul><li>Prevent relapse </li></ul><ul><ul><li>Occasional lapse is fine, but take charge immediately </li></ul></ul><ul><ul><li>Continue to practice newly learned behavior </li></ul></ul><ul><ul><li>Requires “motivation, movement, and monitoring” </li></ul></ul><ul><li>Have social support </li></ul><ul><ul><li>Encouragement from friends/ family/ professionals </li></ul></ul>
  49. 58. Dieting Can Be Hazardous To Your Health <ul><li>Weight regained consists of a higher percentage of body fat than before </li></ul><ul><li>Less healthy than before dieting </li></ul><ul><li>Weight loss diet should not be considered unless you are committed and motivated </li></ul>
  50. 59. Diet Drugs <ul><li>Amphetamine (Phenteramine) </li></ul><ul><ul><li>Prolongs the activity of epinephrine and norepinephrine in the brain </li></ul></ul><ul><ul><li>Decreases appetite </li></ul></ul><ul><ul><li>Not recommended for long term use </li></ul></ul><ul><li>Sibutramine (Meridia) </li></ul><ul><ul><li>Enhances norepinephrine and serotonin activity </li></ul></ul><ul><ul><li>Decreases appetite(eat less) </li></ul></ul><ul><ul><li>Not recommended for people with HTN </li></ul></ul>
  51. 60. Diet Drugs <ul><li>Orlistat (Xenical) </li></ul><ul><li>Inhibits fat digestion </li></ul><ul><li>Reduces absorption of fat in the small intestine </li></ul><ul><li>Fat is deposited in the feces with its side effects </li></ul><ul><li>Must control fat intake </li></ul><ul><li>Malabsorption of fat-soluble vitamins </li></ul><ul><li>Supplements needed </li></ul>
  52. 61. Homeopathic drug <ul><li>Ephedrine (ma huang) </li></ul><ul><ul><li>Linked to illnesses and death </li></ul></ul><ul><ul><li>Associated with nervous and cardiovascular disorder </li></ul></ul><ul><li>St. John’s Wort </li></ul><ul><ul><li>Antidepressant </li></ul></ul><ul><li>Both taking together </li></ul><ul><ul><li>Not recommended until careful testing is done </li></ul></ul>
  53. 62. Over-The-Counter Diet Aids <ul><li>Phenylpropanolamine – recently banned </li></ul><ul><ul><li>Epinephrine-like drug </li></ul></ul><ul><ul><li>Cause a slight decrease in food intake </li></ul></ul><ul><li>Fiber </li></ul><ul><ul><li>“ Filler” leading to satiety </li></ul></ul><ul><ul><li>Causes stomach distention </li></ul></ul><ul><li>Benzocaine </li></ul><ul><ul><li>Numbs the tongue and taste buds </li></ul></ul>
  54. 63. Gastroplasty - Stomach Stapling <ul><li>Common surgical procedure for treating severe obesity </li></ul><ul><li>Reduces the stomach size (from 4 cups) to half a shot glass size (1 oz) </li></ul><ul><li>Overeating will result in rapid vomiting </li></ul><ul><li>Smaller stomach promotes satiety earlier </li></ul><ul><li>75% will lose ~50% of excess body weight </li></ul><ul><li>Costly </li></ul><ul><li>Dumping syndrome </li></ul>
  55. 64. Gastroplasty (Fig. 13-13) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  56. 65. Underweight is Also a Problem <ul><li>15-25% below healthy weight or BMI of <18.5 </li></ul><ul><li>Associated with increased deaths, menstrual dysfunction, pregnancy complications, slow recovery from illness/surgery </li></ul><ul><li>Causes are the same as for obesity but in the opposite route </li></ul>
  57. 66. Treatment for Underweight <ul><li>Intake of energy-dense foods (energy input) </li></ul><ul><li>Encourage meals and snacks </li></ul><ul><li>Reduce activity (energy output) </li></ul><ul><li>To gain a pound you need a total excess intake of 2700-3500 kcal </li></ul>
  58. 67. Eating Disorders <ul><li>Anorexia </li></ul><ul><li>Bulemia </li></ul><ul><li>Baryophobia </li></ul><ul><li>Female Athlete Triad </li></ul>