Health PSYCHOLOGY

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Health PSYCHOLOGY

• Weight management and Obesity

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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

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ENERGY IN
ENERGY OUT
BODY MASS and COMPOSITION
GENES
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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.

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Body Mass Index (BMI kg/m2)

• http//www.nhlbisupport.com/bmi/
• BMI Categories
• Underweight lt18.5
• Normal weight 18.5-24.9
• Overweight 25-29.9
• Obesity BMI of 30 or greater

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When we eat too muchor 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)

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Relationship between BMI and Mortality
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Factors That Contribute to Obesity

• Heredity / biological factors
• Cultural factors
• Emotional / behavioral factors

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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)

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Smell

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

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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

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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 individuals 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

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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

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ob/ob mouse
normal mice
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ob/ob mouse
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ob/ob mouse
ob/ob mouse injected with leptin
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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.

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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)

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Obesity Trends

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

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Factors That Contribute to Obesity

• Heredity / biological factors
• Cultural factors
• Emotional / behavioral factors

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10,000 years ago who survived during a famine?
OR
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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
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Just as our jeans no longer fit our waist, our
genes no longer fit our environment
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Social/Cultural Factors in Obesity

• We live in a toxic environment. Its like trying
  to treat an alcoholic in a town where theres 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 (Natl Geo. Article
  The heavy cost of fat)

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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)

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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 Hersheys
Bar 2 oz 7 oz 300 kcal 1000 kcal
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POPCORN
20 Years Ago
Today
270 calories 5 cups
1700 calories21 cups buttered
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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!

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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)

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Social/Cultural Factors in Obesity

• Pima Indians (in Mexico vs. in U.S.)

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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

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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

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Eat an Apple (Doctors 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 patients family to
  promote healthy meals.
• NYTimes Aug 13, 2010

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Eat an Apple (Doctors Orders)
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Cultural interventions

• Farm to table to school movement
• Etc.

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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

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Stepped Care for Obesity