Eating behavior - obesity Flashcards
Biologists explain obesity through an interaction of what?
genes and neurotransmitters
what are concordance rates between first-degree relatives for obesity?
20%-50% suggesting heritability
what was Nans research?
meta analysis
12 twin studies
concordance rates of 60-80% for MZ twins suggests a genetic component to obesity
lockes research?
assessed genomes of 300,000 genomes and found 97 different genes linked to obesity . Polygenic illness
what neurotransmitters are involved in obesity?
seratonin and dopamine
how is serotonin involved in obesity?
serotonin -> regulate eating by inhibiting activity in VMH
VMH is alerted that we are full and triggers satiety
obese people have less serotonin and therefore do not feel full as quickly/easily
what is obesity co-morbid with and why?
depression = low levels of serotonin
obesity = low levels of serotonin
they go hand in hand
how is dopamine involved in obesity?
- dopamine stimulates pleasure in hypothalamus and amygdala
- feels pleasure after behaviours of eating
- obese people have less dopamine D2 receptors and dysfunctional dopamine system
- this means less production of dopamine
- less pleasure from small amounts of food
- eat more for more pleasure
Evaluate biological explanation for obesity
+ohia
- cross specie validity
+ wang
- AE - psychological
- reductionist
- deterministic
what was ohias research?
- mice = no c2 receptors for serotonin
- mice overate and developed onset obesity
suggests low levels of serotinin is inolved with obesity
what was wangs research?
found obese people have fewer dopamine receptors in certain areas of the brain
what are the psychological explanations for obesity
- restraint theory
- disinhibition theory
- boundary model
explain restraint theory
- cognitive
- obesity = restrained eating
- setting strict limits and imposing cognitive control over physiology
- this is counter productive
- end up over eating
- trying to ignore food makes u focus on food and over eating becoming obese
explain disinhibition theory
includes everything in restraint BUT adds that cues around use (media, friends) act as a trigger and cause us to eat
restrained eating is followed by period of disinhibition - eating whatever you want
explain all or nothing thinking in the disinhibition theory
you have one bit of food due to the trigger but then eat loads because youve already had some
Evaluate disinhibition
+ boyce
- savage
- individual differences
-alternative exp
what did boyce do?
found exposure to thinness caused increases in eating in restrained eaters since acted as a cue/trigger
what did wardle do?
assessed food intake of obese women on a diet and control
found those on restrained diet ate more
who developed boundary model
herman and polivy
from BM explain ‘normal’ eating behaviour
- Food intake exists on a continuim
- goes from hungary to full
- at each end of the continuim biology is the main adherent in what we eat
- when we feel a lack of enegry we eat to the satiety boundary
- once weve eaten to a certain point we feel uncomfy and stop eating
- inbetween the continuim is the biological indifference zone
what is the biological indifference zone
biological mechanisms do not make us full or hungry
social and cognitive factors have the most impact on what we eat
for BM explain dieters eating behaviour
- lower hungary boundary and less responsive to feelings of hunger
- higher satiety to boundary and need more food to feel full
- larger zone of biological indifference making them more vulnerable to the effects of disinhibition
- self imposed upper boundary that marks the most they want to eat, this is below satiety boundary
- if they break this boundary they will eat up to and past the satiety boundary
- this is the what the hell phenomena
for BM, how does diet = obesity
when they break cog boundary this = trigger/disinhibitor
they experience what the hell phenomenon
then eat beyond noraml setiety bound
and overeat
Evaluate the boundary model
+ OGDEN
+ PA - dieters should avoid restraint as it leads to disinhibition
- ID
-AT
WHAT DID OGDEN DO?
- non dieters who had the high calorie ate LESS food but dieters who had the high calorie pre-load ate MORE food suggesting their cognitive boundary had been broken
for non-dieters where does eating start and end?
eating starts at hunger boundary and ends at satiety boundary
why are dieters more vulnerable to cues/disinhibitiors?
because theyre trying so hard to avoid them and control physicality
A01 for biological explanations of obesity
INTERACTION BETWEEN GENES AND NEUROTRANSMITTERS
- genetics
- 20-50% heritability
- Lockes research - polygenic
- Nans research
- neurotransmitters
- serotonin and dopamine
- comorbid with depression
what is obesity?
a complex mental health disorder that occurs when an individual’s weight is higher than what is considered healthy for a persons height.
who conducted a meta analysis on 12 twin studies and found that MZ had concordance rates of 60-80%
NAN
who researched 300,000 peoples genes and found that there are 97
locke
who found that non dieters who had the high calorie ate LESS food but dieters who had the high calorie pre-load ate MORE food suggesting their cognitive boundary had been broken?
ogden
who found that - mice = no c2 receptors for serotonin
- mice overate and developed onset obesity
suggests low levels of serotinin is inolved with obesity
ohia
who found that when assesing food intake if restrictive dieters they ate more then non dieters
wardle
who found that obese people have less d2 receptors in certain areas of the brain
wang
who found that when EXPOSED to THIN PEOPLE dieters ate more
boyce
