Health Psychology

1
Health Psychology

• Obesity Part 1
• Chapter 8
• PY 470 Hudiburg

2
What is obesity?

• Ways to determine Ideal Body Weight body
  composition, especially fat
• Weight for Height Tables
• Metropolitan Life Insurance Table Table 8.1, p.
  269-270
• Body Mass Index
• Weight (kg)/ height (MxM)
• or (weight (lb)/ height (in x in) )x 705
• For example 510 person weighing 150
• BMI (150/ (70 x70)) x 705 21.6
• compare to Table 8.2, p. 270-271

3
BMI Classifications

• BMI 19-25 Normal Low Risk
• BMI 25-30 Moderately overweight Some Risk
• BMI 30-35 Class 1 obesity High Risk
• BMI 35-40 Class 2 obesity Very High Risk
• BMIgt 40 Class 3 obesity Extreme Risk

BMI gt 30, or 30 lbs. overweight for 5'4" person
for 2005 - CDC
4
What is obesity?

• Americans overweight 66 adults (BMI 25-29),
  23 obese CDC (2003) school age obesity 15
• Approximately 325,000 deaths and 39 to 52
  billion in health care costs have been attributed
  to obesity annually (Flegal, Carroll, Ogden,
  Johnson, 2002).
• Rates by gender and ethnic group F 8.1, p. 272
• 33 increase in the past 20 years in U.S.
• Rates in other countries have increased F 8.2,
  p. 273

5
What are the consequences of obesity?

• Physical consequences
• increased risks of hypertension, kidney disease,
  diabetes, cardiovascular disease, and some type
  of cancer
• Some studies have found as much as a seven-fold
  increase in coronary heart disease (CHD) with a
  BMI of 35 or greater (Ellis, Elliott, Horrigan,
  Raymond, Howell, 1996).
• Manson et al. (1990) F 8.3, p. 273, women in
  top 20 BMI are 3 ½ times more likely to die from
  CHD than lowest 20 BMI based on 115,886 women
  30-55 years old in 1976
• Lowest rate of CHD 18.6 23 BMI for females and
  19.9 22.6 BMI for males American Cancer
  Society
• Problems with type 2 diabetes 80 of case are
  obese and concern for growing number of
  overweight children and adolescences Sinha et
  al. (2000)

6
Social/Psychological Effects of Obesity

• Being perceived as obese can affect how you are
  treated and how you feel about yourself.
• Stereotype obese as slow, lazy, and sloppy, less
  sincere, less friendly, meaner, and more
  obnoxious Rychman et al. (1989)
• Black women are less critical of large black
  women than white women are of large white women
• Obese people are frequently victims of ridicule
  and job discrimination
• Obese women are less likely to be married and
  make less money than comparison groups
• Weight discrimination is greater than race and
  gender discrimination and occurs at every stage
  of employment (hiring, placement, promotion,
  compensation, discipline, and discharge)
• Negative social attitudes even in young children
  age 5 Richardson et al. (1961)
• Reasons for negative attitudes it under the
  persons control he/she could stop eating if
  he/she wanted to stop Dejon (1980) study of
  likeability of normal weight and overweight
  pictures of girls
• Personality characteristics are the same for
  obese and non-obese persons

7
Genetic Factors

• Twin studies reveal a genetic influence on body
  weight - F 8.5, p. 276 Grile Pogue-Geile
  (1991)
• Weight resemble those of biological parents
• Identical twins have closely similar weights and
  BMI, even when reared apart -
• Being overweight is not simply a matter of
  sacrificing too many hot fudge sundaes
• Losing weight is not merely a matter of mind over
  platter.
• Stronger relationship between adopted childrens
  and biological parents weight than adopted
  parents weight F 8.5, p. 276
• Obese parents and obese children 7 neither
  parent, 40 one parent, and 80 both parents

8
Causes for Obesity Genetic Inheritance

• Leptin a protein found that suppresses appetite
  in animals and increases metabolism
• Overweight animals lack the protein Leptin
• Overweight people arent as responsive to Leptin
  as are normal weight people. Leptin is actually
  higher in overweight people than normal weight
  people
• Higher in eating disorders (i.e., BED), higher in
  sleep deprived, Anorexia Nervous have
  hypoleptinaemia
• Metabolism rates influenced by genes high rates
  dont gain and low rates gains weight
• Food preferences for obese men and women Table
  8.3, p. 277 the comfort food?

9
Set Point Theory

• The point at which an individuals weight
  thermostat is set
• When body falls below this weight,
• an increase in hunger and
• lowered metabolic rate acts to restore the lost
  weight
• energy expenditure decreases
• Some researchers doubt that the body has a
  precise set point that drives hunger and believe
  slow, sustained changes in body weight can alter
  ones set point
• Hunger is determined by many factors, including
  learned incentives.

10
Basal Metabolic Rate

• The bodys resting rate of energy expenditure
• To maintain the bodys set point weight, your
  body adjusts not only food intake and energy
  output but also the metabolic rate.
• By the end of their 24 week semi starvation, the
  subjects in Ancel et al. (1950) research had
  stabilized at ¾ their normal weight while
  eating half of what they previously did. Study
  was done in the 1930s in Minnesota.
• In a reverse experiment (Levine et al., 1999) in
  which volunteers were overfed 1000 calories a day
  for 8 wks some gain average of 9 lbs. when
  others 1 lb. - those who gained the least weight
  tended to spend the caloric energy fidgeting more.

11
Genetic factors or environmental factors?

• Genes mostly determine why one person today is
  heavier than another. Environment mostly
  determines why people are heavier today than 50
  years ago.
• While the average North American woman weighs
  more than her counterpart of 40 years ago and
  obesity rates are increasing, todays average
  Miss America contestant weights about 15 pounds
  less than 40 years ago.
• Genetic factors predict 40-70 of variation in
  BMI
• Genes for weight gain predisposes some
  individuals towards weight gain
• Environment determines which of those individuals
  actually gain weight

12
Genetic factors or environmental factors?

• Genes do not totally predict weight
• rates of obesity in US have increased
  dramatically in recent years
• people with same genetic make-up who live in
  different areas of the world often have different
  body weights (e.g., Japanese who move to Hawaii
  are heavier than those who stay in Japan)

13
How do psychological factors influence eating
(and overeating)?

• Internal-external hypothesis
• people ignore internal cues (i.e., hunger), and
  pay attention to external cues (i.e., taste,
  smell, variety)
• Limitations -people of normal weight are not
  particularly good at interpreting internal
  signals for hunger
• people of varying weights are good at responding
  to external cues for eating
  

14
Internal/external hypothesis

• PUSHED by physiological state (internal) and
  PULLED by psychological state (external).
• External Incentives and Hunger
• Judity Rodin and Joyce Slochower (1976)
• External girls (could not resist MMs) gained the
  most weight.
• Rodin (1984)
• Subjects had gone 18 hours without food
• While blood samples were taken a juicy steak was
  wheled in, crackling as it was taken off the
  grill
• Rodin monitored their rising blood insulin levels
  and their feelings of hunger
• Externals had the greatest insulin increase and
  accompanying hunger response.
• External incentive (steak) affects internal
  physiological state.

15
Internal/external hypothesis

• Increased variety of foods leads to increased
  consumption even in rats Sclafani Spring
  (1976)
• Box 8.1, p. 279 Schacter et al. (1968) test of
  the internal/external hypothesis. Used a cracker
  rating test, the number of crackers eating by
  normal weight persons was influence by just eaten
  a large meal but there was no influence for
  overweight persons F 8.6, p. 280
• Nisbett (1968) ice cream study used good-tasting
  and bad-tasting ice cream, neither non obese nor
  obese participants ate much bad-tasting ice cream
  but the obese participants ate much more
  good-tasting ice cream than non obese
  participants
• Culture and Hunger
• Cultural preferences vary with exposure
• We tend to dislike unfamiliar (including novel
  foods)
• Research suggests with repeated exposure , their
  appreciation for new tastes increases exposure
  to one set of novel foods increases willingness
  to try another.
• Little recent support for hypothesis

16
How do psychological factors influence eating
(and overeating)?

• Mood regulation
• people eat to make themselves feel better when
  they experience stress, anxiety, or depression
  Pine (1985)
• this tendency is more common for women than men
• Females eat more when depressed than males,
  college student study by Rozin Fallon (1988)
• mixed evidence obese students eat more during
  exam period than students of normal weight (no
  difference during less stressful times). Stress
  does not lead everyone to overeat, especially men.

17
How do psychological factors influence eating
(and overeating)?

• Restraint theory internal physiological signals
  cue hunger Herman Pevy (1984)
• when people are trying to lose weight they ignore
  internal signals, and use cognitive rules to
  limit their intake
• Cognitive rules related to forbidden foods and
  all-or-none approach. If violated all is lost
  therefore over consumption occurs
• Herman Mack (1975) found in a study when
  participants were given either none (control),
  one, or two milkshakes prior to tasting three ice
  creams to rate. Participants were allowed to eat
  as much ice cream to get a rating. Data in F.
  8.7, p. 283, dieters consumed more than non
  dieters as compared to controls.
• Mood influences eating in restrained eaters, when
  played sad music restrained eaters ate more F
  8.8, p. 285
• Restraint theory not always a good predictor of
  eating behavior Lowe (1993)

18
How do psychological factors influence eating
(and overeating)?

• Lifestyle and culture
• people eat more when with others social cues
  The turkey eating orgy and dont forget the pecan
  pie with ice cream.
• What mothers eat while pregnant may influence
  taste preferences in children Mennela et al.
  (2001) study with expectant mothers drinking
  carrot juice
• culture influences types of food and tastes dog
  or snake for dinner? Bugs are a good source of
  protein.
• cultural factors like availability and amount of
  food contribute to obesity U.S. has highest
  rate of obesity change in proportions over the
  years, the supersize generation and video games.

19
Portion size?
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An 11 year old has succeeded.
20
Portion size?

• Largest Hamburger The Absolutely Ridiculous
  Burger was recently prepared in February 2008 at
  Mallies Sports Bar and Grill in Detroit. The
  burger weighs 134 pounds, with cheese and bacon.
  The bun weighs 50 pounds. The burger must be
  order 24 in advance and takes 12 hours to prepare
  and costs 350. Previous record was 123 pounds.