Eating Behaviour

Eating Behaviour

1. Attitudes to food

   • Social Learning Theory
     • Parental Modelling
       • Brown and Ogden
         • correlation between children and parents regarding eating motivation and body dissatisfaction
       • Meyer and Gast
         • (10 to 12 year olds) positive correlation between peer influence and disordered eating - demonstrating they are eaily impressionable and manipulated
     • Media
       • MacIntyre et al
         • 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
   • Mood
     • Garg et al
       • comfort eating: sad film (36% more popcorn eaten) compared to happy film, where ppts ate more nutritionally
         • food use as restoration of mood
           • - Parker et al: eating chocolate (as an emotional eating strategy) prolongs negative mood, not alliviates

2. Neural mechanisms

   • Lashley's Dual Control Theory
     • 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
   • Aphagia = absence of eating due to damage to LH
     • Wickens
       • manipulation of NPY, injecting into rats which then continued eating, even when experiencing satiation
         • neurotransmitter controls eating, supporting dual control theory
         • stimulant
         • - Marie et al
           • no consequential decrease in eating behaviour of mice when genetically manipulated to produce no NPY
   • Hyperphagia = overeating due to damaged to VMH
     • particularly paraventicular nucleus
       • Gold
         • it is only when PVN was included in brain damage hyperphagia occured
         • PVN detects specific food for our body's needs, so responsible for cravings
   • Leptin
     • protein which regulates fat storage, those who don't eat much use up fat and cells cease to secrete leptin
       • Zhang et al
         • injecting ob/ob mice caused them to dramatically lose weight
           • real world application
             • treating obesity, targeting those with high levels of leptin
   • Gherlin
     • stimulant
     • comfort eating
   • homeostasis
   • Amydala, Inferior Prefrontal Cortex
     • cognitive factors e.g. sights and smells, lead to feelings of hunger
       • select food on based on previous experiences
         • Rolls and Rolls
           • removing amydala from rats showed they'd eat familiar and unfamiliar food
             • Kluver Bucy syndrome
               • eating indiscriminately and non-food items

3. Evolutionary approach to eating behaviour

   • environment of evolutionary adaptation (EEA)
     • Denton
       • innate preference for salt - survival value
     • Stanford
       • (monkey brains) humans adapted to eat diverse foods
         • adaptive advantage to meat eating
     • Desor
       • newborns prefer sweetness
     • Garcia
       • taste aversion
         • + helps explain neophobia (fear of foods)
         • through lab experiment with rats who became ill after consuming saccharin, discovered ancestors past to avoid poisonous substances
     • - masks proximate causes e.g. laziness, advertising/media influence
   • weaknesses
     • cultural variations e.g. can't explain spicy foods in Asia
     • fossils are difficult to analyse
     • have we stopped evolving?
       • surely we no longer desire fatty foods because we don't need them

4. Dieting

   • Restraint Theory
     • Herman and Mack
       • 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)
         • 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
   • Cognitive Boundary Model
     • Herman and Polivy
       • unrestrained eaters eat until satisfied, restrained eaters eat until they reach cognitive boundary (self determined)
         • experiment results: low cal preload stay within boundary high cal preload pushed beyond, disinhibits behaviour
         • + implications for obeisty = don't restrain individuals
         • - cannot explain disorders - self report technique - doesn't explain inhibition
   • Denial
     • Wagner et al
       • experiment: do/don't think of the white bear
         • don't deny yourself foods
   • Successful dieting
     • Thomas and Stern
       • creating group contacts for weight loss was successful, importance of social support
       • Lowe et al
         • 71.6% of Weight Watchers maintained a body weight loss of at least 5%

5. Psychological approach to Anoxeria Nervousa

   • Sociocultural
     • Westernised standard of attractiveness = media influences e.g. thin models lead to body dissatisfaction
       • - Hoek et al
         • 6 cases of AN in Non Western culture, not a product of media or peer influence
       • + Uni of West of England
         • looking at thin models report low body dissatisfaction compared to looking at landscape pictures
     • - ethnicity/cultural differences = in Non Western cultures, the bigger the individual, the more attractive/wealthy they are
       • - Cachelin and Regan
         • no significant difference between African Americans and white ppts
     • peer influence
       • + Einsberg
         • peer pressures/dieting among friends related to disordered behaviour e.g. use of pills
       • - Shroff and Thompson
         • no correlation of eating behaviour among friends
   • Psychodynamic
     • reaction to sexual abuse due to loathing of body for appearing attractive
     • reflection of reluctance to take on adult responsibilites, by preventing development of breasts and hips
     • low self esteem, believe not worthy of having food
     • battle against controlling parents
       • Bruncj
         • parents of anoxerics tend to be domineering, AN sufferers gain control of body
   • Cogntive
     • AN a result of maladaptive thought processes
       • 1) Polarised thinking = either/or otherwise they've failed
       • 2) Overgeneralisations = relating a past experience to present/future
       • 3) Catastrophising = fixating on small things
       • 4) Megical Thinking = happiness is achieved once a goal has been reached
     • + Fairburn et al
       • greatest risk factors are perfectionism and negative self image
     • - Halmi et al
       • perfectionism tends to run in families (genetic predisposition) so genes increase risk of developing personality type which will develop AN
     • + Fallon and Rozin
       • use student ppts to rate body silhouettes
         • both men and women rated thinner silhouettes to be more attractive, women wished they were smaller than 'current' size

6. Biological approach to Anoxeria Nervousa

   • Neural
     • anorexia is a symptom of anxiety due to high levels of seratonin
       • Bailer et al
         • 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
       • Kaye et al
         • 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
     • neurodevelopment
       • pregnancy
         • 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
         • 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
   • Evolutionary
     • reproductive suppression hypothesis
       • Surbey
         • 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
       • Guisinger
         • AN linked to migrating populations
           • single minded search for food -> losing weight -> psychological mechanisms conserve energy -> increase desire for food
           • anorexics feel full
   • twins
     • Holland
       • higher concordance rate of MZ to DZ twins, significant genetic involvement in the cause of AN
         • however, twins share shame environment, difficult to conclude single cause