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Energy Balance and Obesity
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Energy Balance and Obesity

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  • 1.  
  • 2.  
  • 3. Energy Balance
    • “ State in which energy intake, in the form of food and /or alcohol, matches the energy expended, primarily through basal metabolism and physical activity”
    • Positive energy balance
      • Energy intake > energy expended
      • Results in weight gain
    • Negative energy balance
      • Energy intake < energy expended
      • Results in weight loss
  • 4. Energy Balance
  • 5. Estimating Kcal Content in Food
    • Bomb calorimeter
    • Burns food inside a chamber surrounded by water
    • Heat is given off as food is burned
    • The increase in water temperature indicates the amount of energy in the food
  • 6. Fat Storage
    • FAT
    • Most fat is stored directly into adipose tissue
    • Body has unlimited ability to store fat (as fat)
    • CARBOHYDRATES
    • Limited CHO can be stored as glycogen
    • Most CHO is used as a energy source
    • Excessive CHO will be synthesized into fat (for storage)
  • 7. Protein and Fat Storage
    • Protein is primarily used for tissue synthesis
    • Adults generally consume more protein than needed for tissue synthesis
    • Excess protein is used as a energy source
    • Some protein will be synthesized into fat (for storage)
  • 8. Macronutrients and Fat Storage
    • Body prefers to use CHO as energy source
    • Only excess intake of CHO and protein will be turned into fat
    • Fat will remain as fat for storage
    • Physical activity encourages the burning of dietary fat
    • Beta-oxidation
    • Most endurance athletes burn fatty acids for energy
    • glycogen is used also
  • 9. Energy In Vs. Energy Out NEAT Basal Metabolism Dietary Intake Physical Activity Thermic Effect of food
  • 10. Basal Metabolism
    • The minimum energy expended to keep a resting, awake body alive
    • ~60-70% of the total energy needs
    • Includes energy needed for maintaining a heartbeat, respiration, body temperature
    • Amount of energy needed varies between individuals
  • 11. Influences On Basal Metabolism
    • Body surface area (weight, height)
    • Gender
    • Body temperature
    • Thyroid hormone
    • Age (2% decline/decade past 30)
    • Kcal intake
    • Pregnancy
    • Use of caffeine and tobacco
  • 12. Measurement of Body’s Energy Needs
    • Direct calorimetry
      • Measures heat output from the body using an insulated chamber
      • Expensive and complex
    • Indirect calorimetry
      • Measures the amount of oxygen a person uses
      • A relationship exists between the body’s production of energy and oxygen
  • 13. Physical Activity
    • Increases energy expenditure beyond BMR
    • Varies widely among individuals
    • More activity, more energy burned
    • Lack of activity is the major cause of obesity
  • 14. 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 energy consumed
    • TEF is higher for CHO and protein than fat
    • Less energy is used to transfer dietary fat into adipose stores
  • 15. Harris-Benedict Equation
    • Estimates resting energy needs
    • Considers height, weight, age, and gender
    • For men:
    • 66.5 + 13.8x(kg) + 5x(cm) - 6.8x(age in yr.)
    • For women:
    • 655.1 + 9.6x(kg) + 1.8x(cm) - 4.7x(age in yr.)
  • 16. Sample Calculations
    • Man : 21 yr., 5’10” (171 cm), 155# (70 kg)
    • 66.5 + 13.8x( 70kg ) + 5x( 171cm ) - 6.8x( 21 ) = 1745 kcal/day
    • Woman : 21 yr., 5’10” (171 cm), 155# (70kg)
    • 655.1 + 9.6x( 70kg ) + 1.8x( 171cm ) - 4.7x( 21 )= 1536 kcal/day
  • 17. Why Do You Eat?
    • Hunger
      • Physiological (internal) drive to eat
      • Controlled by internal body
    • Appetite
      • Psychological (external) drive to eat
      • Often in the absence of hunger
      • e.g., seeing/smelling fresh baked chocolate chip cookies
  • 18. Satiety Regulator
    • The hypothalamus
      • When feeding cells are stimulated, they signal you to eat
      • When satiety cells are stimulated, they signal you to stop eating
    • Sympathetic nervous system
      • When activity increases, it signals you to stop eating
      • When activity decreases, it signals you to eat
  • 19. Influences of Satiety
  • 20. Influences of Satiety
  • 21. Influenced By Body Composition
    • Leptin
    • A hormone produced by the adipose tissue
    • Increases with larger fat mass (and decrease desire to eat)
    • Decreases with lower fat mass (and enhance desire to eat)
    • Acts to decrease activity of neuropeptide Y
    • Neuropeoptide Y
    • Increases food intake
    • Reduces energy expenditure
  • 22. Hormonal Influence
    • Endorphins
      • Natural body tranquilizer that can prompt you to eat
    • CCK
      • Along with gastrointestinal distention, decreases hunger (and desire to eat)
    • Serotonin
      • Neurotransmitter that is released as a result of CHO intake
      • High levels appear to decrease desire to eat CHO and induce calmness
  • 23. Hormonal Influence
    • Nutrient receptors
    • In small intestine
    • Elicit feeling of satiety
    • Communicate with the brain via nerves
    • Inform brain of the presence of nutrients in the small intestine
    • Feeling of satiety with the infusing of CHO or fats in the small intestine
  • 24. Nutrients Influence
    • Presence of energy yielding nutrient registers satiety in the brain
    • Apolipoprotein A-IV on the chylomicrons signals satiety in the brain
    • Absence of these nutrients will signal hunger
  • 25. What is a Healthy Body Weight?
    • Based on how you feel, weight history, fat distribution, family history of obesity-related disease, current health status, and lifestyle
    • Current height/weight standards only provide guides
  • 26. Body Mass Index (BMI)
    • The preferred weight-for-height standard
    • Calculation:
    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
  • 27. 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.
  • 28. Obesity
    • Excessive amount of body fat
      • Women with > 30-35% body fat
      • Men with > 25% body fat
    • Increased risk for health problems
    • Are usually overweight
    • Measurements using calipers
  • 29. Estimation of Body Fat
    • Underwater weighing
    • Most accurate
      • Fat is less dense than lean tissue
      • Fat floats
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 30. Estimation of Body Fat
    • Bioelectrical impedance
      • Low-energy current to the body that measures the resistance of electrical flow
      • Fat is resistant to electrical flow; the more the resistance, the more body fat you have
    • X-ray photon absorptiometry
      • An X-ray body scan that allows for the determination of body fat
    • Infrared light
      • Assess the interaction of fat and protein in the arm muscle
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 31. Body Fat Distribution
    • Upper-body (android) obesity--”Apple shape”
    • Associated with more heart disease, HTN, Type II Diabetes
    • Abdominal fat is released right into the liver
    • Fat affects liver’s ability to clear insulin and lipoprotein
    • Encouraged by testosterone and excessive alcohol intake
    • Defined as waist to hip ratio of >1.0 in men and >0.8 in women
  • 32. Body Fat Distribution
  • 33. Body Fat Distribution
    • Lower-body (gynecoid) obesity--”Pear shape”
    • Encouraged by estrogen and progesterone
    • Less health risk than upper-body obesity
    • After menopause
    • upper-body obesity appears
  • 34. 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
  • 35. An Epidemic of Obesity
  • 36. OBESITY
    • 61% of adults in the United States were overweight or obese (BMI > 25) in 1999.
    • 13% of children aged 6 to 11 years and 14% of adolescents aged 12 to 19 years were overweight in 1999. This prevalence has nearly tripled for adolescents in the past 2 decades.
    • The increases in overweight and obesity cut across all ages, racial and ethnic groups, and both genders.
    • 300,000 deaths each year in the United States are associated with obesity.
    • Overweight and obesity are associated with heart disease, certain types of cancer, type 2 diabetes, stroke, arthritis, breathing problems, and psychological disorders, such as depression.
    • The economic cost of obesity in the United States was about $117 billion in 2000.
  • 37. Juvenile-Onset Obesity
    • Develops in infancy or childhood
    • Increase in the number of adipose cells
    • Adipose cells have long life span and need to store fat
    • Makes it difficult to loose the fat (weight loss)
    • Causes
    • poor dietary patterns
    • lack of physical activity
    • 43% of adolescents watch 2 hours or more of TV/day
  • 38. Adult-Onset Obesity
    • Develops in adulthood
    • Fewer (number of) adipose cells
    • These adipose cells are larger (stores excess amount of fat)
    • If weight gain continues, the number of adipose cells can increase
  • 39. Causes of Obesity
    • Nature debate
    • Identical twins raised apart have similar weights
    • Genetics account for ~40% of weight differences
    • Genes affect metabolic rate, fuel use, brain chemistry
    • Thrifty metabolism gene allows for more fat storage to protect against famine
  • 40. Causes of Obesity
    • 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
  • 41. Nature and Nurture
    • Obesity is nurture allowing nature to express itself
    • Location of fat is influenced by genetics
    • A child with no obese parents has a 10% chance of becoming obese
    • A child with 1 obese parent has a 40% chance
    • A child with 2 obese parents has a 80% chance
  • 42. Nature Vs. Nurture
    • Those at risk for obesity will face a lifelong struggle with weight
    • Gene does not control destiny
    • Increased physical activity, moderate intake can promote healthy weight
  • 43. 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
  • 44. Why Diets Don’t Work
    • Body defends itself against weight loss
    • Thyroid hormone concentrations (BMR) drop during weight loss and make it more difficult to lose weight
    • Activity of lipoprotein lipase increases making it more efficient at taking up fat for storage
  • 45. Why Diets Don’t Work
    • Weight cycling (yo-yo dieting)
    • Typically weight loss is not maintained
    • Weight lost consists of fat and lean tissue
    • Weight gained after weight loss is primarily adipose tissue
    • Weight gained is usually more than weight lost
    • Associated with upper body fat deposition
  • 46. Why Diets Don’t Work
    • Weight gain in adulthood
    • Weight gain is common from ages 25-44
    • BMR decreases with age
    • Inactive lifestyle
    • Changes in body composition
    • Fluid is usually the first weight lost
    • Loss in lean body tissue means lowering the BMR
    • Very little fat is lost during weight loss
  • 47. Lifestyle Vs. Weight Loss
    • Prevention of obesity is easier than curing
    • Balance energy in(take) with energy out(put)
    • Focus on improving food habits
    • Focus on increase physical activities
  • 48. What It Takes To Lose a Pound
    • Body fat contains 3500 kcal per pound
    • Fat storage (body fat plus supporting lean tissues) contains 2700 kcal per pound
    • Must have an energy deficit of 2700-3500 kcal to lose a pound per week
  • 49. 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
  • 50. Sound Weight Loss Program
    • Meets nutritional needs, except for kcal
    • Slow & steady weight loss
    • Adapted to individuals’ habits and tastes
    • Contains enough kcal to minimize hunger and fatigue
    • Contains common foods
    • Fit into any social situation
    • Chang eating problems/habits
    • Improves overall health
    • See a physician before starting
  • 51. Cutting Back
    • Control calorie intake by being aware of kcal and fat content of foods
    • “Fat Free” does not mean “Calories Free” (or “All You Can Eat”)
    • Read food labels
    • Estimate kcal using the exchange system
    • Keep a food diary
  • 52. Regular Physical Activity
    • Fat use is enhanced with regular physical activity
    • Increases energy expenditure
    • Duration and regularity are important
    • Make it a part of a daily routine
  • 53. Behavior Modification
    • Modify problem (eating) behaviors
    • Chain-breaking
    • Stimulus control
    • Cognitive restructuring
    • Contingency management
    • Self-monitoring
  • 54. Cognitive Restructuring
    • Changing your frame of mind regarding eating
    • Replace eating due to stress with “walking”