2. Energy BalanceEnergy 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
3. Energy In: Food CompositionEnergy In: Food Composition
• Direct measure of
food’s energy value
• Bomb calorimeter
• Indirect measure of
energy released
• Oxygen consumed
• kCalorie calculations
4. Energy In: Food IntakeEnergy In: Food Intake
• Hunger
• Physiological response to nerve signals and
chemical messengers
• Hypothalamus
• Influences
• Satiation – stop eating
• Satiety – not to start eating again
6. Energy In: Food IntakeEnergy In: Food Intake
• Overriding hunger and satiety
• Stress eating
• External cues
• Time of day, availability, sight, taste of food
• Environmental influences
• Examples
• Cognitive influences
• Disordered eating
7. Energy In: Food IntakeEnergy In: Food Intake
• Sustaining satiation and satiety
• Nutrient composition
• Protein is most satiating
• Low-energy density
• High-fiber foods
• High-fat foods – strong satiety signals
8. Energy In: Food IntakeEnergy In: Food Intake
• The hypothalamus
• Control center for eating
• Integrates messages
• Energy intake, expenditure, storage
• Gastrointestinal hormones
9. Energy OutEnergy Out
• Thermogenesis
• Basal metabolism
• Physical activity
• Food consumption
• Adaptation
10. Energy Out: Basal MetabolismEnergy Out: 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)
12. Energy Out: Physical ActivityEnergy Out: 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
13. Energy Out: Thermic Effect ofEnergy Out: Thermic Effect of
FoodFood
• 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
14. Energy Out: AdaptiveEnergy Out: Adaptive
ThermogenesisThermogenesis
• Adapt to dramatically changing
circumstances
• Examples
• Extra work done by body
• Amount expended is extremely variable
• Not included in energy requirement
calculations
16. Estimating EnergyEstimating Energy
RequirementsRequirements
• 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
17. Defining Healthy Body WeightDefining Healthy Body Weight
• Ideal
• Not appearance based
• Perceived body image and actual body size
• Damaging behaviors
• Subjective
• Little in common with health
19. Defining Healthy Body WeightDefining 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
22. Distribution of Body Weights inDistribution of Body Weights in
US AdultsUS Adults
23. Body Fat and Its DistributionBody 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
24. Body Fat and Its DistributionBody Fat and Its Distribution
• Needing less body fat
• Some athletes
• Needing more body fat
• Example groups
• Fat distribution
• Visceral fat
• Central obesity
• Subcutaneous fat
25. ““Apple” and “Pear” BodyApple” and “Pear” Body
Shapes ComparedShapes Compared
26. Body Fat and Its DistributionBody 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
28. Health Risks Associated withHealth Risks Associated with
Body Weight & Body FatBody 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
30. Health Risks Associated withHealth Risks Associated with
Body Weight & Body FatBody 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
31. Health Risks Associated withHealth Risks Associated with
Body Weight & Body FatBody 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
32. Health Risks Associated withHealth Risks Associated with
Body Weight & Body FatBody Weight & Body Fat
• Inflammation & metabolic syndrome
• Change in body’s metabolism
• Cluster of symptoms
• Fat accumulation
• Inflammation
• Elevated blood lipids
• Promote inflammation
• Fit and fat versus sedentary and slim
39. Anorexia NervosaAnorexia 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
40. Anorexia NervosaAnorexia 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
41. Anorexia NervosaAnorexia 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
42. Bulimia NervosaBulimia 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
43. Bulimia NervosaBulimia Nervosa
• Binge-purge cycle
• Lack of control
• Consume food for emotional comfort
• Cannot stop
• Done in secret
• Purge
• Cathartic
• Emetic
• Shame and guilt
44. The Vicious Cycle of RestrictiveThe Vicious Cycle of Restrictive
Dieting & Binge EatingDieting & Binge Eating
45. Bulimia NervosaBulimia 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
46. Bulimia NervosaBulimia 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
47. Diet Strategies for CombatingDiet Strategies for Combating
Bulimia NervosaBulimia Nervosa
48. Binge-Eating DisorderBinge-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
49. Eating Disorders in SocietyEating 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
