Eating Behaviour

1. Restraint theory

2. The role of denial

3. The role of detail

1. Restraint eating = synonymous w/dieting

2. Klesges et al (1987) suggests as much as 89% of female population in UK consciously restrain food intake at some pt in lives

3. Herman and Mack (1975)'s Restraint theory suggests attempting not to eat actually increases the probability of overeating

4. The boundary model is an application of the restraint theory girl:

Herman and Polivy (1984) suggest according to this model - hunger keeps intake of food above certain minimum + satiety works to keep intake below max level

5. Gap between the two levels - psychological factors have greatest impact on size

6. Dieters tend to have a larger range between hunger + satiety levels as it takes longer for them to feel hungry + more food to feel satisfied

7. Restrained eaters have a self-imposed desired intake

- once they've gone over this boundary, they continue to eat until they reach satiety (i.e. beyond max level imposed as pt of their diet)

1. Research into cognitive psych = shown attempting to suppress/deny a thought frequently has the reverse effect, making it more prominent

2. Wegner et al (1987) asked some patients not to think about a white bear but to ring a bell if they did

- others told to think about white bear

3. Findings:

- those told not to think about bear rang bell far more often than pps instructed to think about bear

4. Wegner refers to this phenomenon as 'theory of ironic process of mental control'

- bc it represents a paradoxical effect of thought control (i.e. denial often backfires)

1. Redden (2008) suggests the secret of successful dieting lies in attention we pay to what is being eaten

2. He claims people usually like experiences less as they repeat them

- when it comes to dieting, this makes it harder to stick to a particular regime

3. To overcome this, instead of thinking of the meals as a whole, the idea is to pay attention to specifics of the recipe to make it seem less repetitive

- e.g. the dreaded salad - should focus on type of tomatoes in it or the salad leaves i.e rocket etc

4. Redden (2008) jelly bean experiment

- 135 pps each given 22 jelly beans

1. Wardle and Beales (1988)

2. Wegner (1994)

3. Redden (2008)

4. Rodin et al (1977)

Randomly assigned 27 obese women to either diet group (focused on restrained eating patterns), an exercise group or non-treatment group 4 seven weeks

- At weeks four + six, all pps were assessed under lab conditions

- At week 4, food intake + appetite were assessed before + after a 'preload' (i.e. small snack like milkshake or chocolate)

- At week 6, food intake was assessed under stressful condition

Findings:

Results showed that at both assessment sessions, women in the diet condition ate more than women in the exercise + non-treatment group

Admits the 'ironic' effects observed in research are not particularly huge

As experimental effects go, they are detectable but far from overwhelming

135 pps each given 22 jelly beans

Split into two groups: general and specific

One group received general info about jelly bean (e.g. jelly bean number 7) and the other received specifics (e.g. jelly bean number 8 is cherry flavoured)

Findings:

- Participants got bored with eating beans faster ifthey saw the general information and enjoyed task more with specific info

- Shows the decline in enjoyment of an eating regimedepends on how much repetition people perceive,

- The study also has implications for our understandingsof dieting. Variety of categories is especially useful when facing limitedoptions or following a repetitive regimen.

- The research establishes that sub-categorizationoffers people the potential to make their lives more enjoyable.

Carried out a study to assess the baseline psychological predictors of successful weight loss

They found that individual's beliefs about the cause of obesity + motivation for weight loss played an important role

1. Limitations of anecdotal evidence

Many studies of dieting success or failure rely on personal accounts of individuals (anecdotal evidence)

- such evidence is often used to justify claims concerning particular dieting strategies

- however anecdotal evidence is based on memory and memory isn't 100% accurate, nor is the assessment of success or failure of dieting entirely objective

1. Free will vs determinism?

- its likely many genetic mechanisms exert influence on weight, suggesting he success or failure may be determined by factors other than individual's choice of lifestyle

- lipoprotein lipase helps to store calories as fat

- if too much is produced the body will sort more fat + makes it easier to regain weight

2. Cultural bias in obesity research

- Research in this area is biased bc some cultural groups find it harder to diet successfully bc of natural inclination to obesity

E.g. asian adults are more prone to obesity than Europeans

1. Homeostasis

2. The hypothalamus

3. Neruotransmitters

1. Homeostasis involves mechanisms which both detect the state of the internal environment (e.g. whether the body has enough nutrients) and also correct the situation to restore that environment to its optimal state

2. There's a signif time lag btwn mechanisms operating to restore equilibrium, + the body registering their effect

3. By the time an individual has eaten enough to restore energy levels, only a small amount of food has been digested

- thus receptors responsible for detecting nutrient levels insufficient 'data' to to turn off eating

4. Body has evolved tow separate systems - one for turning 'on' and one for turning 'off'

- among humans, glucose levels probs play the most important role in producing feelings of hunger

5. Decline in glucose activates the lateral hyp which results in hunger feelings

6. Rise in glucose levels activates the ventromedial hyp which leads to feelings of satiation

- which in turn inhibits further feeding

7. In some animals this doesn't happen, as can be seen from studies of protein leptin

1. Investigation into role of hyp in eating began in 1950s when researchers discovered damage to lateral hypothalamus in rats caused condition aphagia

2. Researchers also found stimulation of the LH elicits feeding behaviour

- these opposing effects of injury + stimulation led researchers to conclude that they had discovered the 'on' switch for eating behaviour

3. Researchers also discovered that damage to the ventromedial hyp caused rats to overeat - leading to a condition called hyperphagia

4. Stimulation of this area inhibited feeding

- this led researchers to conclude that VMH signals stop eating as result of many glucose receptors in that area

5. Damage to the nerve fibres passing through VMH tends to also damage another area called paraventricular nucleus (PVN) and is now believed that PVN alone causes hyperphagia

- PVN also detects specific foods for our body needs, and consequently seems responsible or many of our 'cravings'

1. Cognitive aspect of food includes the images of food we have in memory and also food-related sights and smells

2. Neural control of these cognitive factors in hunger probably originates in two main areas:

the amygdala and the inferior prefrontal cortex

3. The amygdala - its role is thought to be primarily in selection of foods on basis of previous experience

4. e.g. Rolls and Rolls found surgically removing the amygdala in rats would cause the animals to consume both familiar and novel foods indiscriminately

- whereas non surgically modified rats would initially avoid novel foods + consume only the more palatable familiar foods instead

5. Inferior prefrontal cortex receives msgs from the olfactory bulb (pt of brain responsible for smell)

6. Bc odours influence taste of foods, damage to inferior prefrontal cortex is thought to decrease eating because of diminished sensory responses to food odour + probably to taste

1. Three main neurotransmitters found to influence appetite are catecholamines, serotonin and dopamine

2. Catecholamines include neurotransmitters like dopamine, norepinephrine and epinephrine

- they are fight or flight hormones tAnother neural mechanism involved in controllingeating behaviour is neurotransmitters. The three main neurotransmitters foundto influence appetite are catecholamines, serotonin and dopamine.Catecholamines include neurotransmitters like dopamine, norepinephrine andepinephrine, and are ‘fight-or-flight’ hormones that are released as a responseto stress; serotonin is found extensively in the gastrointestinal tract and itactives the muscles used for feeding. One neurotransmitter that is involved inincreasing food intake is norepinephrine – injections of NE in the hypothalamuscan stimulate feeding if injected into the paraventricular nucleus, and canreduce feeding if injected into the perifornical area. One neurotransmitterwhich decreases food intake is cholecystokinin (CCK); this is a hormonereleased when food is detected in the duodenum, and causes a reduction ofappetite and satiation.

1. Baylis et al (1996)

2. Gold (1973)

3. Marie et al (2005)

4. Zald and Pardo (1997)

Found that rats that had lesions in their VMN and became obese, whereascontrol rats had not, concluding that the VMN must play a role in satiation aslesions caused hyperphagia and obesity

Found that lesions restricted to the VMN did not lead to hyperphagia andonly led to overeating when there is damage to other areas like theparaventricular nucleus

Found that in genetically manipulated mice thatdon’t produce neuropeptide y, there was no subsequent decrease in feedingbehaviour, but when genetic injections were administered it caused hunger

They provided physiological evidence to support the claim that the amygdala participates in the emotional processing of olfactory stimuli

- they exposed healthy adult pps to aversive olfactory stimuli while measuring blood flow to the amygdala by means of PET scan

- exposure to unpleasant odours produced significant blood flow increases to the amygdala whereas non-aversive odours didn't

- increased blood flow to amygdala = also associated w/subjective ratings of perceived unpleasantness of stimuli

1. Approaches - an evolutionary approach

if a decline in body's energy resources below optimal level is not major cause of huger then what is

Evol psychs suggest that primary stimulus for hunger + eating is food's positive incentive value

- i.e. people eat bc they normally relish for particular tastes that are in nature associated w/foods that promote our survival (e.g. meat or salt)

2. Real world application

- research indicated NPY found in lateral hyp has important role in eating behaviour

- this suggests that one of main reasons why overweight people continue to eat too much is bc brain produces NPY in excessive amounts

- NPY is also produced in abdolminal fat

- suggests this leads to a vicious cycle where NPY produced in brain leads t more eating + prod of more fat cells

- by targeting individs w/more NPY, it should be possible to prevent obesity before it happens

1. Culture

2. Mood

3. Social learning theory

1. SLT emphasises impact that observing other people has on our own attitudes + behaviour (food specifically)

2. Parental modelling = one way in which kids acquire eating behaviour + attitudes to food

- observing behaviour of parents

- attitudes to food = inevitably affect children bc parents control foods bought + served in home

3. Research also suggests associated between parents' and children's attitudes to food generally

- Ogden and Brown (2004) report consistent correlations between parents + their children in terms of snack food intake, eating motivations + body dissatisfaction

4. Media effects - the role of SLT is evident in the impact of TV and other media (i.e. magazines)

5. Macintyre et al (1998) found that the media have a major impact on both what people eat + their attitudes to certain foods

6. Researchers also state that many eating behaviours are limited by personal circumstances, i.e. age, income + family circumstances

7. Thus people appear to learn from the media about healthy eating, but must place info w/in broader context of their lives

1. Much of research into attitudes to food + eating behaviour = focused on body dissatisfaction

- the cause of body dissatisfaction + consequent influence on eating behaviour includes the following:

2. Ethnicity: research suggests body dissatisfaction + related eating concerns + disorders = more characteristic of white women than black or asian (Powell and Khan, 1995)

3. Ball and Kennedy (2002) studied over 14,000 women between ages of 18 and 23 in Australia

= Results showed for all ethnic groups, the longer the time spent in Australia, the more women reported attitudes + eating behaviours similar to women born in Australia

4. This is known as the 'acculturation' effect

5. Another way which culture affects eating behaviour is social class

- Number of studies found that body dissatisfaction, dieting behaviour + eating disorders are more common in higher-class individuals

6. Dornbusch et al (1984) surveyed 7000 american adolescents + concluded that higher-class females had a greater desire to be thin

- + were more likely to diet to achieve this, than lower class counterparts were

7. Another way in which social class influences attitudes to food is in terms of healthy eating

8. Recent study used data from the 2003 Scottish Health Survey + established that in general, income was +vely associated w/healthy eating

9. This could be because they have more money, they are more inclined to spend money on healthier foods which tend to cost more than junk

1. Mumford et al (1991)

2. Striegel-Moore et al (1995)

3. Leshem (2009)

4. Story et al (1995)

The incidence of bulimia nervosa was greater among Asian school girls than among their white counterparts

More evidence of a 'drive for thinness' among black girls than among white girls

Compared three groups of women + found that:

- the diet of urban Bedouin women was hardly different from the desert Bedouins

- Both their diets differed significantly from the Jewish women's

- they had a significantly higher salt intake

In a sample of American students, higher social class was related to greater satisfaction w/weight and lower rates of weight control behaviours

- i.e. vomiting

SHOWS NO RELATIONSHIP BETWEEN CLASS + LOWERED EATING BEHAVIOUR

1. Meyer and Gast (2008)

2. Birch and Fisher (2000)

3. Birch et al (1980)

They surveyed 10-12 year old girls + boys

Found a signif +ve relationship between peer influence + disordered eating

- the likability of peers was considered the most important factor in the relationship

The role of social learning is also supported in the study of mothers + daughters by Birch + Fisher (2000)

They found that the best predictors of the daughters' eating behaviour = the mothers' dietary restraint their perception of the risks of the daughters becoming overweight

They used peer modelling to change children's preference for vegetables

Findings:

When children sat next to peers who preferred a vegetable diff to themselves, their preference had changed + this was evident a few weeks later

- Also children who didn't like vegetables at beginning of study said they liked them by the end

1. A soc learning exp of eating focuses explicitly on the role of fashion models influencing food attitudes of young people

- hwvr - attitudes to food are clearly a product of much more than SLT alone

- evol exps for food preference suggest our preference for fatty + sweet foods is a direct result of an evolved adaptation among our distant ancestors

1. Stress

2. Binge-eating

1. Much research shows that during times of stress, eating behaviour changes

2. Stone + Browned (1994) recorded daily records of stress + eating patterns of 158 students for 84 days

- reported eating less = predominant response to stress

3. Greeno and Wing (1994) proposed 2 hypothesis - explaining why stress caused both increase and decrease in eating

4. General effect hypothesis - proposes stress changes patterns of food consumption

- animal studies show physical stressors (tail pinching + electric shocks) cause change in eating behaviour

5. Individual differences hypothesis - stress leads to changes only in certain groups

- e.g. cools et al (1992) reported stress only triggered increased eating in people already dieting

1. Individuals w/bulimia complain of anxiety prior to binge

2. Self-monitoring studies show that 1hr before binge, bulimics had more negative mood states than 1hr before normal snack/meal

3. Same relationship between low mood + binge eating appears to be the same for sub-clinical populations

4. Wegner et al (2002) had students record eating patterns + mood states over 2-week period

- binge days = characterised by generally low mood compared to non binge days

- but no difference in mood before + after binge

5. Suggesting although mood may make binge-eating more likely, eating doesn't alleviate mood state

1. We often reach for junk food when feeling a little low

2. Garg et al (2007) observed food choices in 38 pps watching a funny movie (Sweet home alabama) or a sad movie (love story)

- Pps were offered buttered popcorn and seedless grapes throughout films

3. Findings: those who watched the sad film consumed 36% more popcorn than those watching an upbeat film

- but an upbeat film group ate far more grapes than the sad film group

4. Garg also found if nutritional info about food was given prior to viewing, consumption of unhealthy foods dropped dramatically

1. Wegner et al (2002)

2. Connor et al (1991)

3. Parker et al (2006)

4. Garg et al (2007)

Had students record eating patterns + mood states over 2-week period

- binge days = characterised by generally low mood compared to non binge days

- but no difference in mood before + after binge

No evidence than individual differences affect the relationship between eating and mood

- there was a signif +ve correlation between hassles + snacking

- no significant relationship between these two variables was found in pps who rated low on external eating, or for other possible moderators of hassle snacking

Found that although chocolate has a slight antidepressant effect for some people

- wen consumed as an emotional eating strategy, its more likely to prolong rather than alleviate -ve mood, particularly if used repeatedly

- Pps were offered buttered popcorn and seedless grapes throughout films

Findings: those who watched the sad film consumed 36% more popcorn than those watching an upbeat film

- but an upbeat film group ate far more grapes than the sad film group

Also found if nutritional info about food was given prior to viewing, consumption of unhealthy foods dropped dramatically

1. Gender bias

2. Problems of generalisability (methodological issues)

- studies come from variety of groups, some clinical w/eating disorder and some sub-clinical, and others who represent a non-clinical population

- This puts limitations on the degree to which we can generalise from one group to another