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 5�10� 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 BMI> 40; Class 3 obesity; Extreme Risk A rating of 25 or higher is considered overweight, 30 or higher is obese, and 40 or higher is extremely obese. For example, a 5-foot-8-inch person who weighs 190 pounds would be overweight; a person at the same height who weighs 230 pounds is obese. - Americans are even fatter than they think they are, with nearly a third of all adults - almost 59 million people - rated obese in a disturbing new government survey based on actual body measurements. One in five Americans, or 19.8 percent, had considered themselves obese in a 2000 survey based on people's own assessments of their girth. The new 1999-2000 survey puts the real number at 31 percent - a doubling over the past two decades. The new number is considered more reliable since people consistently underestimate their weight. A rating of 25 or higher is considered overweight, 30 or higher is obese, and 40 or higher is extremely obese. For example, a 5-foot-8-inch person who weighs 190 pounds would be overweight; a person at the same height who weighs 230 pounds is obese. - Americans are even fatter than they think they are, with nearly a third of all adults - almost 59 million people - rated obese in a disturbing new government survey based on actual body measurements. One in five Americans, or 19.8 percent, had considered themselves obese in a 2000 survey based on people's own assessments of their girth. The new 1999-2000 survey puts the real number at 31 percent - a doubling over the past two decades. The new number is considered more reliable since people consistently underestimate their weight.

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 � 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 children�s and biological parent�s weight than adopted parent�s 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 aren�t 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 don�t gain and low rates gains weight Food preferences for obese men and women � Table 8.3, p. 277 � the comfort food? Oh 128 videoOh 128 video

9. Set Point Theory The point at which an individual�s �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 one�s set point Hunger is determined by many factors, including learned incentives.

10. Basal Metabolic Rate The body�s resting rate of energy expenditure To maintain the body�s 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 � 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, today�s 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 M&Ms) 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 don�t 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?

20. Portion size? Largest Hamburger � The �Absolutely Ridiculous Burger� was recently prepared in February 2008 at Mallie�s 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.