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Nutrition - Chapter 7 Notes
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  • 1. Chapter 7 Lecture Outline Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display
  • 2. Energy Balance
    • 65% of adults are overweight
    • 30% of total population is obese
    • Red flags:
      • 10 pounds of weight gain
      • 2-inch increase in waist circumference
  • 3. Energy Balance
  • 4. Estimating kcal Content in Food
  • 5. Energy In vs. Energy Out Adaptive Thermogenesis Basal Metabolism Dietary Intake Physical Activity Thermic Effect of food
  • 6. Basal Metabolism
    • Minimum energy expended to keep a resting, awake body alive
    • ~60-70% of total energy needs
    • Includes energy needed for maintaining heartbeat, respiration, body temperature
    • Amount of energy needed for basal metabolism varies between individuals
    • Approximately 1 kcal/minute
  • 7. Factors that Influence Basal Metabolism
    • Body surface area (weight, height)
    • Lean body mass
    • Gender
    • Body temperature
    • Thyroid hormone
    • Nervous system activity
    • Age
    • Calorie intake
    • Pregnancy
    • Use of caffeine and tobacco
  • 8. Physical Activity
    • Increases energy expenditure
    • More activity, more energy burned
    • Lack of activity is a major cause of obesity
  • 9. Thermic Effect of Food (TEF)
    • Energy used to digest, absorb, and metabolize food nutrients
    • “Sales tax” of total energy consumed
    • ~5-10% above the total calories consumed
    • TEF is highest for protein > carbohydrate > fat
  • 10. Adaptive Thermogenesis
    • Nonvoluntary physical activity
      • Triggered by overeating
      • Fidgeting and shivering
      • Maintenance of muscle tone
      • Maintenance of posture
    • Overeating
      • Increases sympathetic nervous system activity
    • Resists weight gain
  • 11. Determination of Energy Needs
    • Direct calorimetry
      • Measures heat output
      • Expensive and complex
    • Indirect calorimetry
      • Measures the amount of oxygen consumed
      • Oxygen consumed is related to energy expended
  • 12. Estimated Energy Requirement (EER)
    • Men 19 years and older:
    • EER= 662-(9.53 x AGE) + PA x (15.91 x WT + 539.6 x HT)
    • Women 19 years and older:
    • EER= 354- (6.91 x AGE) + PA x (9.36 x WT + 726 x HT)
      • PA = physical activity estimate
      • WT = weight in kg
      • HT = height in meters (inches / 39.4)
  • 13. Physical Activity Estimate 1.45 1.48 Very Active (walks the equivalent of ~17 miles/day) 1.27 1.25 Active (walks the equivalent of ~7 miles/day) 1.12 1.11 Low Activity (walks the equivalent of ~2 miles/day) 1.00 1.00 Sedentary (no exercise) PA (WOMEN) PA (MEN) ACTIVITY LEVEL
  • 14. What is a Healthy Body Weight?
    • Current height/weight standards
      • Weight associated with health and longevity
      • May not be the healthiest weight for individual
    • Review of family history
    • Personal weight history
    • Healthy lifestyle contribution
  • 15. Weight-Related Conditions
  • 16. A Healthy Body Weight
    • What is the lowest weight maintained for more than a year?
    • What weight was maintained without constantly feeling hungry?
    • Establish a “personal” healthy weight
  • 17. BMI: Overweight and Obesity
    • Underweight = BMI < 18.5
    • Healthy weight = BMI 18.5-24.9
    • Overweight = BMI 25-29.9
    • Obese = BMI 30-39.9
    • Severely obese = BMI >40
  • 18. Height / Weight Table
  • 19. Perspective on Weight
    • Aim for personal healthy weight
    • Avoid unrealistic goals
    • Listen to body’s cues (for hunger)
    • Eat a healthy diet
    • Be physically active
    • “Size acceptance”
  • 20. Obesity
    • Excessive amount of body fat
      • Women > 35% body fat
      • Men > 25% body fat
    • Increased risk for health problems
    • Are usually truly overweight
  • 21. Estimation of Body Fat
    • Underwater weighing
    • Most accurate
    • Fat is less dense than lean tissue
    • Fat floats
  • 22. Estimation of Body Fat
    • Air displacement
    • Determines the body volume
      • Displace air in a sealed chamber
    • Body density =
    • Body wt/body volume
    • % Body fat=
    • (495/body density)-450
  • 23. Skinfold Measurements
  • 24.
    • Insert Figure 7-10, p. 248Bioelectrical impedance
  • 25. Estimation of Body Fat
    • Bioelectrical impedance
      • Low-energy current that measures the resistance of electrical flow
      • Fat is resistant to electrical flow; the more the resistance, the more body fat
    • DEXA (dual x-ray photon absorptiometry)
      • X-ray body scan that allows for the determination of body fat
      • Very accurate but expensive
  • 26. Body Fat Distribution
    • Upper-body obesity, “Apple shape”
    • Associated with
      • Cardiovascular disease, HTN, type 2 diabetes
      • Testosterone and excessive alcohol
      • Abdominal fat is released into the liver and promotes inflammation in the body
    • Defined as
      • Waist measurement of > 40” for men
      • Waist measurement of >35” for women
  • 27. Body Fat Distribution
  • 28. Body Fat Distribution
    • Lower-body obesity, “Pear shape”
    • Encouraged by estrogen and progesterone
    • After menopause, upper-body obesity more common
    • Fewer health risks than upper-body obesity
  • 29. Juvenile-Onset Obesity
    • Develops in infancy or childhood
    • Increase in the number of adipose cells
    • Adipose cells have long lifespan and need to store fat
    • Makes it difficult to lose fat (weight loss)
  • 30. Adult-Onset Obesity
    • Develops in adulthood
    • Fewer (number of) adipose cells
    • Adipose cells are larger (store excess amount of fat)
    • If weight gain continues, the number of adipose cells can increase
  • 31. Obesity and Nature Debate
    • Identical twins
      • When raised apart still have similar weights
    • Genes
      • Affect metabolic rate, fuel use, brain chemistry, body shape
      • Account for up to 70% of weight differences
    • Thrifty metabolism gene
      • More fat storage to protect against famine
  • 32. Set-Point Theory
    • Weight is regulated by the body
    • Genetically predetermined body weight
    • Body resists weight change
    • Leptin assists in weight regulation
    • Reduction in calorie intake results in lower metabolic rate
    • Ability to shift the set-point weight?
  • 33. Opponents of Set-Point Theory
    • Weight does not remain constant
    • Different environments can alter weight
    • People settle into a particular weight based on current circumstances
  • 34. Obesity and Nurture Debate
    • Environmental factors influence weight
    • Learned eating habits
    • Activity factor (or lack of)
    • Poverty and obesity
    • Female obesity is rooted in childhood obesity
    • Male obesity appears after age 30
  • 35. Nature and Nurture
    • Obesity is nurture allowing nature to express itself
    • Location of fat is influenced by genetics
    • Child of obese parents is especially at risk
    • Increased physical activity and moderate calorie intake can promote healthy weight
  • 36. What Encourages Excess Body Fat?
  • 37. Why Diets Don’t Work
    • Obesity is a chronic disease
      • Treatment requires long-term lifestyle changes
    • Dieters are misdirected
      • More concerned about weight loss than healthy lifestyle
      • Unrealistic weight expectations
  • 38. Looking for a Sound Weight-Loss Program?
    • Seek advice from a Registered Dietitian
    • Control calorie intake
    • Increase physical activity
    • Acknowledge need for lifelong changes to maintain healthy weight
  • 39. Weight-Loss Triad
  • 40. Control Calories
    • Sedentary society---requires less calories
    • Low-fat, high-fiber approaches
      • Most successful in long-term studies
    • No diet has a “metabolic advantage”
    • Read food labels
    • Keep a food log (portion size awareness)
  • 41. Regular Physical Activity
    • Important for weight maintenance
    • Promotes steady weight loss
      • Expends 100-300 kcal while controlling calories
    • Boosts self-esteem
    • Add weight resistance
      • Increase lean body mass
      • Increase fat use
      • Increase bone health
      • Increase metabolic rate
  • 42. Physical Activity Recommendations
    • 60 minutes/day to maintain body weight
    • 60-90 minutes/day for maintenance of weight loss
    • Pedometer
      • Goal 10,000 steps a day
  • 43. What it Takes to Lose a Pound
    • Body fat contains 3500 kcal per pound
    • Fat storage (body fat plus supporting lean tissues) contains 3300 kcal per pound
    • Must have an energy deficit of about 3300 kcal to lose a pound per week
  • 44. Do the Math To lose one pound, you must create a deficit of 3300 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 about 500 kcal per day - 500 kcal x 7 days = - 3500 kcal = ~ 1 pound of weight day week loss in 1 week
  • 45. Sound Weight Loss Program
    • Rate of loss
    • Flexibility
    • Intake
    • Behavior modification
    • Overall health
  • 46. Behavior Modification
    • Modify problem (eating) behaviors
    • Chain-breaking
    • Stimulus control
    • Cognitive restructuring
    • Contingency management
    • Self-monitoring
  • 47. Chain-Breaking
    • Breaking the link between two behaviors
    • These links can lead to excessive intake
  • 48. Stimulus Control
    • Altering the environment
      • Minimize the stimuli for eating
    • Putting you in charge of temptations
  • 49. Cognitive Restructuring
    • Changing your frame of mind regarding eating
    • Replacing eating due to stress with “walking”
  • 50. Contingency Management
    • Forming a plan of action
      • Response to a situation
    • Rehearsing appropriate responses
      • The pressure of eating at parties
  • 51. Self-Monitoring
    • Tracking foods eaten and conditions affecting eating
    • Understanding your eating habits
  • 52. Weight Maintenance
    • Prevent relapse
      • Occasional lapse is fine, but take charge immediately
      • Continue to practice newly learned behavior
      • Requires “motivation, movement, and monitoring”
    • Have social support
      • Encouragement from friends/ family/ professionals
  • 53. Diet Drugs
    • Amphetamine (Phenteramine)
      • Prolongs the activity of epinephrine and norepinephrine in the brain
      • Decreases appetite
      • Not recommended for long-term use (dependency)
    • Sibutramine (Meridia)
      • Enhances norepinephrine and serotonin activity
      • Decreases appetite
      • Not recommended for people with HTN
  • 54. Orlistat (Xenical)
    • Inhibits (lipase) fat digestion
    • Reduces absorption of fat by 30% in the small intestine
    • Dietary fat is deposited in the feces, with resulting side effects
    • Must still control fat intake
    • Malabsorption of fat-soluble vitamins
    • Supplement needed at bedtime
    • Alli---Low dose of Orlistat, available OTC
  • 55. Treatment of Severe Obesity
  • 56. Very Low-Calorie Diets (VLCD)
    • Recommended for people >30% above their healthy weight
    • 400-800 kcal per day
    • Low carbohydrate and high protein
    • Cause ketosis
    • Lose ~3-4 pounds a week
    • Require careful physician monitoring
    • Health risks include cardiac problems and gallstones
  • 57. Bariatric Surgery
  • 58. Adjustable Gastric Banding
    • Reduces opening from esophagus to stomach by gastric band
    • Decreases amount of food eaten
    • Band can be inflated or deflated
  • 59. Gastroplasty - Stomach Stapling
    • Most common surgical procedure for treating severe obesity
    • Reduces the stomach size
      • From 4 cups to 1 oz (shot glass size)
    • Overeating will result in rapid vomiting
    • Smaller stomach promotes satiety earlier
    • 75% will lose ~50% of excess body weight
  • 60. Gastroplasty
  • 61. Criteria for Gastroplasty
    • BMI > 40
    • Obese for > 5 years
    • No history of alcoholism
    • No history of major psychiatric disorder
    • Costly procedure
    • Follow-up needed after procedure loss
    • Requires major lifestyle changes
  • 62. Underweight is Also a Problem
    • BMI of <18.5
    • Associated with increased deaths, menstrual dysfunction, pregnancy complications, slower recovery from illness/surgery
  • 63. Treatment for Underweight
    • Intake of energy-dense foods (energy input)
    • Encourage regular meals and snacks
    • Reduce activity (energy output)
    • Increase portion size
    • Strength training
  • 64. Fad Diets
    • Promote quick weight loss
    • Limited food selections
    • Use of testimonials
    • Cure-alls
    • Recommend expensive supplements
    • No permanent lifestyle changes advocated
    • Critical of the scientific community
  • 65. Types of Popular Diets
    • Low or restricted carbohydrates
    • Carbohydrate focused diets
    • Low-fat approaches
    • Novelty diets
    • Meal replacements
  • 66. Popular Diets