Eating behaviour (food)
- Created by: Maddie
- Created on: 28-12-13 09:28
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- Eating Behaviour
- Explanations of attitudes to food
- Cultural Influences
- Ethnicity
- Eating disorders and concerns are more common in white women than Asian or Black women (Powell and Khan)
- Social class
- Dieting and eating disorders are more likely in higher-classed individuals (Dornbusch et al)
- Ethnicity
- Mood and eating behaviour
- Davis et al found that an hour before binge eating, individuals were in a depressed mood
- Garg et al found that people eat more unhealthy foods when placed in front of a depressing film
- Synoptic links
- Gender bias- tendency to focus on only women
- Cultural differences- may influence attitude to food
- Cultural Influences
- The impact of dieting
- Restraint theory
- Attempting not to eat increases to probability of overeating
- Women in diet conditions ate more than women in non diet conditions (Wardle and Beale)
- Boundary Model (Herman and Polivy)
- A dieter must stop eating before they reach satiety as their gap between hunger and satiety is larger than the average person
- The role of denial
- Theory of ironic processes- denial of food thoughts may backfire
- Attempt to suppress thoughts of food makes them more prominent (Soetens et al)
- Detail
- Successful dieting by focusing on specific details of each meal
- Jelly bean experiment- participants focused on flavours rather than number of jelly beans
- Successful dieting by focusing on specific details of each meal
- Synoptic links
- Free will or determinism?- high levels of LPL mean greater weight gain
- Asian adults more prone to obesity than Europeans
- Anecdotal evidence- less trustworthy compared to scientific studies
- Restraint theory
- Role of neural mechanisms
- Homeostasis
- The body's tendency to maintain a constant internal environment
- Decline in blood glucose levels activates LH
- Rise in blood glucose levels activates VMH
- Lateral hypothalamus (LH) and ventromedial hypothalamus (VMH)
- Change to LH leads to aphagia, stimulation to eating behaviour
- Damage to LH doesn't only affect feeding behaviour
- NPY 'turns on eating' if injected into LH
- Damage to VHM causes animals to overeat (hyperphagia)
- Stimulation of VMH inhibits feeding
- Zhang's ob/ob mice-leptin
- Change to LH leads to aphagia, stimulation to eating behaviour
- Neural control of cognitive factors
- Amygdala- selection of foods on basis of food preference
- Inferior frontal cortex- damage decreases eating because of decreased sensory responses
- Kluver-Bucy syndrome- damage to brain areas lead to increased appetite and indiscriminate eating
- Zald and Pardo-physiological evidence to support role in emotional processing of olfactory stimuli
- Synoptic links
- Evolutionary approach- primary stimulus for hunger and eating is food's positive incentive-value.
- Body produces ghrelin in response to stress; also boosts appetite
- Real-world application- NPY also produed by abdominal fat, which leads to more eating and more fat
- Homeostasis
- Evolutionary explanations of food preference
- The EEA
- Environment in which human beings first emerged as separate species
- Natural selection favoured adaptations that promoted survival in EEA
- Early diets
- Fatty foods adaptive for energy resources
- Evolved preference for foods rich in calories
- Preferences for meat
- Fossil evidence suggests early diet mainly animal-based foods
- Unlikely early humans would have had enough energy from meat free diet
- Taste Aversion
- Animals who became ill after eating developed an aversion to that food
- Development of taste aversion helped ancestors to survive
- Taste aversions difficult to shift once learned
- Medicine effect- animals learn preference for foods that make them healthier
- Commentary
- Importance of calorie-rich foods demonstrated in studies of young children
- Anthropological evidence dismisses suggestion that ancestors were vegetarian
- Some food preferences have not been a product of evolution
- Taste aversion explained by concept of biological preparedness
- Application- understanding of taste aversion acquired during chemotherapy
- Synoptic links
- Preference for fatty foods reflected in success of fast food restaurants
- Comparative evidence- chimps in Gombe National park
- Evolved preferencs are modified by cultural factors
- The EEA
- Obesity
- Obesity often runs in families
- Stunkard et al estimated from studies of 25,000 pairs of twins that male identical twins reared apart had a BMI estimated at 70% heritable for males and 66% for females.
- Adoptive parents and children do not share genetic material but share a common environment. If obesity is genetic then there should be more similarity with biological than adoptive parents.
- Genetic influences have an important role in determining adult weight, whereas environment seems to have little effect
- Storing lots of fat in times of plenty improves survival chances in times of famine.
- The environment was much more unpredictable for our ancestors, leading to uncertainties about food supply
- A useful strategy would be to eat as much as possible whenever they could so that if famine arrived then they would have stored fat to see them through
- Chamala et al
- Modern Pima Indians show unusally high levels of obesity
- They suggested that this provided an evolutionary advantage for their ancestors
- The Pima would have lived in harsh barren desert-like conditions.
- Their genes provided them with the maximum advantage from any food they found.
- They suggested that this provided an evolutionary advantage for their ancestors
- Modern Pima Indians show unusally high levels of obesity
- BMI
- 18.5- Underweight
- Weight (kg) divided by height (metres squared)
- 25- Overweight
- 30- Obese
- 40- Morbidly Obese
- Obesity often runs in families
- Explanations of attitudes to food
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