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Health PSYCHOLOGY

Health PSYCHOLOGY

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Health PSYCHOLOGY

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  1. Health PSYCHOLOGY Weight management and Obesity

  2. Weight Management -- Overview • Physical activity (what does “Obesity” article say?) • Dietary choices (what does “Obesity” article say?) • Caloric needs • Vary by age, sex, height, weight, activity level, & basal metabolic rate (BMR) • Rough guideline (men = 2500 kcal, women = 2000 kcal) • Mood regulation • Cultural factors

  3. ENERGY IN ENERGY OUT BODY MASS and COMPOSITION GENES

  4. Assessing body composition Estimating percentages of fat, muscle, bone Is there an “ideal” body comp? • Bioelectrical impedance — determining body fat percentage by analyzing electrical resistance (fat is a poor conductor) • Skin calipers — thickness of subcutaneous fat in multiple places on the body • Body mass index (BMI) – used to estimate a healthy body weight based on a person's height, assuming an average body composition.

  5. Body Mass Index (BMI = kg/m2) http://www.nhlbisupport.com/bmi/ BMI Categories: • Underweight = <18.5 • Normal weight = 18.5-24.9 • Overweight = 25-29.9 • Obesity = BMI of 30 or greater

  6. When we eat too much…or move too little (or both) • Obesity (particularly “apple-pattern”) linked to atherosclerosis, hypertension, diabetes • Increased risk of several cancers, sleep disturbances, degenerative joint disease • Impact on psychological well-being • Increased mortality rates (next slide)

  7. Relationship between BMI and Mortality

  8. Factors That Contribute to Obesity • Heredity / biological factors • Cultural factors • Emotional / behavioral factors

  9. Basic physiological cues • Body needs energy = sends orexigenic signal (tells brain to switch hunger on) • Ghrelin (hormone) • Body has sufficient energy = sends anorexigenic signal (tells brain to switch hunger off) • Leptin (hormone)

  10. Smell Only sense directly connected to forebrain Olfactory receptor neurons (350 ORNs) Strong cue for eating, emotion, and memory 10

  11. Taste Taste buds (5 different types) Salt, sour, bitter, sweet, umami (savory) each contains several types of taste receptors (microvilli) that react with tastant molecules in food Taste is influenced by many factors 11

  12. Metabolism and weight • Basal Metabolic Rate (BMR) • base rate of energy expenditure • influenced by heredity, age, activity level, and body composition (fat tissue has a lower metabolic rate) • Set Point • the point at which an individual’s “weight thermostat” is supposedly set • when the body falls below this weight, an increase in hunger and a lowered metabolic rate may act to restore the lost weight

  13. “Is it genetic?” • ob gene • Regulates production of leptin • Leptin is secreted by fat cells and has dual activity of decreasing food intake and increasing metabolic rate • Mice born without the ability to make leptin (ob/ob mice) eat without restraint

  14. ob/ob mouse normal mice

  15. ob/ob mouse

  16. ob/ob mouse ob/ob mouse injected with leptin

  17. So, just give obese humans leptin!!! • In fact, this works in leptin-deficient humans, but… • 99.99% of obese humans have HIGH levels of leptin, but have become insensitive to it.

  18. Hereditary factors • The genetic contribution to body weight is estimated to be between 40 and 70 percent (with some rare cases of severe obesity linked to specific gene errors) • Body weights of adopted children correlate more strongly with weights of biological parents • The epigenetics of increasing weight through the generations -- Maternal obesity could promote obesity in the next generation. (Waterland, 2008)

  19. Obesity Trends • http://www.cdc.gov/obesity/data/trends.html • Will the trend continue?

  20. Factors That Contribute to Obesity • Heredity / biological factors • Cultural factors • Emotional / behavioral factors

  21. 10,000 years ago – who survived during a famine? OR

  22. ENERGY IN ENERGY OUT Most are not in a famine anymore… Increased availability of high density foods (sugar/fat are cheap) Increase in size Decrease in cost Decrease in work- related activities Decrease in activities of daily living BODY MASS Genetic predisposition to store fat

  23. Just as our jeans no longer fit our waist, our genes no longer fit our environment

  24. Social/Cultural Factors in Obesity We live in a toxic environment. It’s like trying to treat an alcoholic in a town where there’s a bar every ten feet. Bad food is cheap, heavily promoted, and engineered to taste good. Healthy food is hard to get, not promoted, and expensive. If you came down from Mars and saw all this, what else would you predict except an obesity epidemic? Kelly Brownell, Yale, 2004 (Nat’l Geo. Article: The heavy cost of fat)

  25. Social/Cultural Factors in Obesity • Food-toxic environment (cheap, hi-cal, lo-quality food available) • Absence of supermarkets in lo-income neighborhoods • Way too many of our calories are coming from junk food (and in the car). (Sugar: 172 lbs/pp per year) • Governmental subsidies (e.g., Zea Mays, a giant tropical grass) • We are simply eating more! (next slides)

  26. Humongasize it!! Past Today French Fries 2.4 oz 7 oz 210 kcal 610 kcal Soda 6.5 oz 20.0 oz 79 kcal 250 kcal Hershey’s Bar 2 oz 7 oz 300 kcal 1000 kcal

  27. POPCORN 20 Years Ago Today 270 calories 5 cups 1700 calories21 cups buttered

  28. Social/Cultural Factors in Obesity • 2004: The "Monster Thickburger" — two 1/3-pound slabs of Angus beef, four strips of bacon, three slices of cheese and mayonnaise on a buttered sesame seed bun • 1420 calories!

  29. Social/Cultural Factors in Obesity • Cultural variation in ideal body image (overemphasis on thinness  yo-yo dieting and eventual weight gain) • Studies on immigrants: e.g., Japanese-American men are 3 times as likely to be obese as men living in Japan • Pima Indians (next slide)

  30. Social/Cultural Factors in Obesity Pima Indians (in Mexico vs. in U.S.)

  31. Emotional / behavioral factors • Disinhibition— overeating triggered by an event, emotion, or behavior • Eating used as coping • Internality / Externality hypothesis • People are sensitive to external cues, perhaps more so in overweight individuals: • Time of day • Commercials • “Golden arches”

  32. Dieting concerns • Dieting • In U.S., 72% of women and 44% of men have dieted at some point in their adult lives • Yo-yo dieting associated with progressive wt gain • Chronic dieting influence BMR negatively • Fad diets and health problems

  33. Eat an Apple (Doctor’s Orders) • Doctors at three health centers in Massachusetts have begun advising patients to eat “prescription produce” from local farmers’ markets, in an effort to fight obesity in children of low-income families. Now they will give coupons amounting to $1 a day for each member of a patient’s family to promote healthy meals. NYTimes Aug 13, 2010

  34. Eat an Apple (Doctor’s Orders)

  35. Cultural interventions • Farm to table to school movement • Etc.

  36. Healthy Weight Loss • Cognitive-behavioral program • Goal-setting, monitoring, social support • L.E.A.N. • Lifestyle changes (stimulus control, self-monitoring, speed, etc.) • Exercise • Attitude • Nutrition

  37. Stepped Care for Obesity