Eating Behaviour

Attitudes to food
1. Social Learning Theory
  1. Parental Modelling
    1. Brown and Ogden
      1. correlation between children and parents regarding eating motivation and body dissatisfaction
    2. Meyer and Gast
      1. (10 to 12 year olds) positive correlation between peer influence and disordered eating - demonstrating they are eaily impressionable and manipulated
  2. Media
    1. MacIntyre et al
      1. media can impact on individuals attitudes to some foods
        - individual differences e.g. low income/household circumstances relates to inability to afford healthy foods, and so associated with negative feelings
        - disregards evolutionary approach, adaption for survival
2. Mood
  1. Garg et al
    1. comfort eating: sad film (36% more popcorn eaten) compared to happy film, where ppts ate more nutritionally
      1. food use as restoration of mood
        - Parker et al: eating chocolate (as an emotional eating strategy) prolongs negative mood, not alliviates
Neural mechanisms
1. Lashley's Dual Control Theory
  1. stop eating -> low blood glucose level -> lateral hypothalmus "on" -> sensation of hunger -> eat food -> increase blood glucose level -> ventromedial hypothalamus -> sensation of satiety -> cycle continues
2. Aphagia = absence of eating due to damage to LH
  1. Wickens
    1. manipulation of NPY, injecting into rats which then continued eating, even when experiencing satiation
      1. neurotransmitter controls eating, supporting dual control theory
      2. stimulant
      3. - Marie et al
        no consequential decrease in eating behaviour of mice when genetically manipulated to produce no NPY
3. Hyperphagia = overeating due to damaged to VMH
  1. particularly paraventicular nucleus
    1. Gold
      1. it is only when PVN was included in brain damage hyperphagia occured
      2. PVN detects specific food for our body's needs, so responsible for cravings
4. Leptin
  1. protein which regulates fat storage, those who don't eat much use up fat and cells cease to secrete leptin
    1. Zhang et al
      1. injecting ob/ob mice caused them to dramatically lose weight
        real world application
        treating obesity, targeting those with high levels of leptin
5. Gherlin
  1. stimulant
  2. comfort eating
6. homeostasis
7. Amydala, Inferior Prefrontal Cortex
  1. cognitive factors e.g. sights and smells, lead to feelings of hunger
    1. select food on based on previous experiences
      1. Rolls and Rolls
        removing amydala from rats showed they'd eat familiar and unfamiliar food
        Kluver Bucy syndrome
        eating indiscriminately and non-food items
Evolutionary approach to eating behaviour
1. environment of evolutionary adaptation (EEA)
  1. Denton
    1. innate preference for salt - survival value
  2. Stanford
    1. (monkey brains) humans adapted to eat diverse foods
      1. adaptive advantage to meat eating
  3. Desor
    1. newborns prefer sweetness
  4. Garcia
    1. taste aversion
      1. + helps explain neophobia (fear of foods)
      2. through lab experiment with rats who became ill after consuming saccharin, discovered ancestors past to avoid poisonous substances
  5. - masks proximate causes e.g. laziness, advertising/media influence
2. weaknesses
  1. cultural variations e.g. can't explain spicy foods in Asia
  2. fossils are difficult to analyse
  3. have we stopped evolving?
    1. surely we no longer desire fatty foods because we don't need them
Dieting
1. Restraint Theory
  1. Herman and Mack
    1. preload test (1) high cal (2) low cal "eat as much ice cream as you like" ppts ask if there were a restrained/unrestrained eater (self report)
      1. restrained eater from high cal preload ate more ice cream than low cal preloaders
        positive correlation between amount eaten after high restraint score and the more they consume, demonstrating the 'what the hell' affect = behvaioural inhibiton
2. Cognitive Boundary Model
  1. Herman and Polivy
    1. unrestrained eaters eat until satisfied, restrained eaters eat until they reach cognitive boundary (self determined)
      1. experiment results: low cal preload stay within boundary high cal preload pushed beyond, disinhibits behaviour
      2. + implications for obeisty = don't restrain individuals
      3. - cannot explain disorders - self report technique - doesn't explain inhibition
3. Denial
  1. Wagner et al
    1. experiment: do/don't think of the white bear
      1. don't deny yourself foods
4. Successful dieting
  1. Thomas and Stern
    1. creating group contacts for weight loss was successful, importance of social support
    2. Lowe et al
      1. 71.6% of Weight Watchers maintained a body weight loss of at least 5%
Psychological approach to Anoxeria Nervousa
1. Sociocultural
  1. Westernised standard of attractiveness = media influences e.g. thin models lead to body dissatisfaction
    1. - Hoek et al
      1. 6 cases of AN in Non Western culture, not a product of media or peer influence
    2. + Uni of West of England
      1. looking at thin models report low body dissatisfaction compared to looking at landscape pictures
  2. - ethnicity/cultural differences = in Non Western cultures, the bigger the individual, the more attractive/wealthy they are
    1. - Cachelin and Regan
      1. no significant difference between African Americans and white ppts
  3. peer influence
    1. + Einsberg
      1. peer pressures/dieting among friends related to disordered behaviour e.g. use of pills
    2. - Shroff and Thompson
      1. no correlation of eating behaviour among friends
2. Psychodynamic
  1. reaction to sexual abuse due to loathing of body for appearing attractive
  2. reflection of reluctance to take on adult responsibilites, by preventing development of breasts and hips
  3. low self esteem, believe not worthy of having food
  4. battle against controlling parents
    1. Bruncj
      1. parents of anoxerics tend to be domineering, AN sufferers gain control of body
3. Cogntive
  1. AN a result of maladaptive thought processes
    1. 1) Polarised thinking = either/or otherwise they've failed
    2. 2) Overgeneralisations = relating a past experience to present/future
    3. 3) Catastrophising = fixating on small things
    4. 4) Megical Thinking = happiness is achieved once a goal has been reached
  2. + Fairburn et al
    1. greatest risk factors are perfectionism and negative self image
  3. - Halmi et al
    1. perfectionism tends to run in families (genetic predisposition) so genes increase risk of developing personality type which will develop AN
  4. + Fallon and Rozin
    1. use student ppts to rate body silhouettes
      1. both men and women rated thinner silhouettes to be more attractive, women wished they were smaller than 'current' size
Biological approach to Anoxeria Nervousa
1. Neural
  1. anorexia is a symptom of anxiety due to high levels of seratonin
    1. Bailer et al
      1. persistant disruption of seratonin levels may lead to increased anxiety
        AO3: drug treatment e.g. SSRIs (Selective Seratonin Reuptake Inhibitor), to treat AN
        - makes no difference
        Kaye et al
        prevents relapse
        - lack of food prevents SSRIs functioning
    2. Kaye et al
      1. used PET scans to compre dopamine activity in 10 women recovering from AN and 12 healthy women
        AN due to overactivity in dopamine receptors in the basal ganglia, which interprets harm and pleasure hence why sufferers have difficulty with associating good feelings with food
        + Castro Fornieles et al
        homovanillic acid (waste product of dopamine) higher in girls with AN
  2. neurodevelopment
    1. pregnancy
      1. birth complications
        Lindberg and Hjern
        association between premature birth and AN, brain damage cause hypoxia which impairs neurodevelopment
        Builk
        mother with eating disorder leads to malnurished child
        Favaro et al
        perinatal complications associated with risk of developing AN e.g. placenal infarcion and early eating difficulties and low birth weight
      2. season of birth
        Eagles
        individuals with AN more likely to be born in Spring time (3rd or 4th child)
        due to infections in 2nd trimester (winter) higher temperature during conception
        critical period for brain development
        - in equatorial countries AN patients had no seasonality effect
2. Evolutionary
  1. reproductive suppression hypothesis
    1. Surbey
      1. AN is a result of trying to control the onset of sexual maturation which ceases the menstrual cycle
        benefical as individuals adapt to EEA
        therefore AN is a disordered variant of adaptive ability to alter timing of reproduction
    2. Guisinger
      1. AN linked to migrating populations
        single minded search for food -> losing weight -> psychological mechanisms conserve energy -> increase desire for food
        anorexics feel full
3. twins
  1. Holland
    1. higher concordance rate of MZ to DZ twins, significant genetic involvement in the cause of AN
      1. however, twins share shame environment, difficult to conclude single cause

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Eating Behaviour

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