Professor Glenn Wilson, Gresham College, London

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FEAST OR FAMINE?
THE PSYCHOLOGY OF EATING

• Professor Glenn Wilson, Gresham College, London

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TOO LITTLE, TOO MUCH

• Eating is a major problem.
• In the Developing World many people die because
  they dont have enough food.
• In the West, people die more often because they
  are surrounded by too much. Either they overeat
  and become susceptible to obesity-related
  diseases or they starve themselves by compulsive
  fasting in the midst of plenty. Anorexia is a
  disease of the affluent middle-classes, not the
  poor.
• Around 10 of teenage girls in the UK have some
  kind of eating disorder and there has been a 13
  increase over the last decade (Micali et al,
  2013).

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WEIGHT STEREOTYPES

• Popular belief that people are responsible for
  their own body shape.
• Negative traits are commonly ascribed to
  overweight people which explain and blame them
  for their condition (e.g. lazy, undisciplined).
• Some negative stereotypes also attach to slim
  people (e.g. vain, bitchy, mean).
• Yon Cassius has a lean and hungry look . He
  thinks too much - such men are dangerous.
• (Julius Caesar).

Survey of 1800 women aged 18-40 (Glamour, 2012)
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GENETIC INFLUENCE

• Body weight depends on interplay among many
  genetic and environmental forces.
• Twin studies show 40-70 heritability (Herrera
  et al, 2011). Many genes involved 40 locations
  so far implicated in various appetite, energy
  storage and metabolism processes.
• The best-known obesity-risk gene (FTO) is
  associated with a failure of satiation after
  eating (Karra et al, 2013).
• Epigenetics (gene expression effects without DNA
  alteration) also have impact.
• All of this makes control of weight very
  difficult.
• Though often thought of as faulty the survival
  advantage of obesity genes in lean times is
  obvious.

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EATING HABITS

• Eating, drinking and exercise styles relate to
  obesity in complex ways. In a study of 1356 UK
  adults (Wilson 1985), body weight was associated
  with lack of exercise, overall food intake and
  eating in response to emotional stress. The
  latter seemed to reflect difficulty in
  maintaining dietary restraint in constitutionally
  heavy people. Diets tend to collapse at times
  when people are lonely, stressed or frustrated.
• Sugar consumption and daily drinking were
  unrelated to body weight or health problems
  healthy people perhaps allow themselves more
  luxuries.

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COMFORT EATING

• When a sports team loses, their fans eat more
  junk food the next day.
• Consumption of high calorie food increases on
  Monday in a city whose NFL team has lost on
  Sunday, whereas it decreases in the victors city
  (Cornil Chandon, 2013). Effect is greater in
  cities with the most committed fans, when
  opponents are equally matched and defeats narrow.
  Similar findings with French soccer fans.
• A self-affirmation procedure (ranking and
  discussing core values) showed promise in
  countering the effect of a sports loss.

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PERSONALITY AND BMI

• Impulsivity is the strongest personality
  correlate of weight gain.
• People get gradually heavier with age but those
  in top 10 for impulsivity averaged 24lbs more
  than those in the bottom 10.
• Extravert people were also heavier
  Conscientious and Agreeable people tended to be
  thinner.
• Those high in novelty-seeking were less
  successful in a weight management programme
  (Cloninger et al 2007).
• Diet and exercise require commitment and
  restraint, which are lacking in certain
  individuals.

Longitudinal study of 1,988 adults in Baltimore
(Sutin et al 2011).
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HUNGRY SHOPPERS

• People who shop in a supermarket when hungry
  dont buy more food but do buy more high-calorie
  products (Wansink Tal, 2013). Subjects
  food-deprived for 5 hrs chose 5.72 high calorie
  products, vs 3.95 for sated controls. Interpreted
  as an effect of food insecurity.
• Suggested that weight-watchers should have a
  snack before shopping or go after lunch. Good to
  take a list (ideally not children).

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THINKING YOURSELF FULL

• It is possible to trick people into feeling less
  hungry.
• Brunstrom et al (2012) used a soup bowl that
  would covertly refill or lower its quantity as
  people ate from it. Immediately afterwards,
  self-reported hunger was based on how much they
  had actually consumed. However, after 2/3 hours
  hunger went with how much they thought they had
  consumed (memory of bowl size).
• Food labels emphasising light and diet
  ingredients may be counterproductive, making us
  think we are less satisfied (so we eat more
  later).

People shown a large quantity of fruit that has
supposedly gone into their smoothie feel more
full afterwards (Brunstrom 2012).

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TV MAKES YOU FAT

• Watching TV contributes to obesity in several
  ways.
• Viewers are sedentary for long periods.
• If they snack while watching they lose track of
  how much they have had and consume more later
  (Mittal et al, 2011).
• If the content of the TV programme is
  food-related or depressing they will eat even
  more of any food that is handy (Laran, 2013).

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SLEEP DEPRIVATION

• Late bedtimes allow more waking time for eating
  and late-night snacks tend to be more fattening
  (Spaeth et al 2013).
• Also, sleep loss is apparently stressful.
  Decreased activity in cortical evaluation regions
  of the brain (frontal and insular cortex)
  together with increased amygdala activity prompts
  desire for high-calorie, fattening foods (Greer
  et al 2013).

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SOCIAL INFLUENCES

• People eat more in company than when alone. The
  social facilitation effect is stronger for
  friends/family than with strangers. Several
  reasons (1) Eating is a shared activity that
  consolidates social ties. (2) Meal lasts longer,
  giving more time to eat. (3) Conversation is
  distracting, so self-monitoring is impaired (c.f.
  TV viewing).
• Eating with friends 18 calories, Viewing TV
  14 (Hetherington et al 2006).
• People dining in twos tend to match their
  intake. Women eating with men eat more daintily
  than by themselves or with other women.

Women eat less when men are present than with
other women. Men not affected by company. (Young
et al 2009).
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OBESITY CONTAGION

• Social network analysis (Christakis Fowler,
  2010) indicates that obesity spreads like a
  virus. Friends have similar body build
  neighbours do not. Norms for acceptable body
  build, portion size, etc. may be passed among
  friends to influence weight.

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PRIMING INDULGENCE

• Seeing overweight people can lead us to eat more
  (Campbell Mohr, 2011).
• People walking through a lobby answered survey
  questions that included a picture of either an
  overweight or normal-weight person.
• Afterwards they helped themselves to a bowl of
  wrapped sweets as a thank you.
• Those who saw the larger model took more sweets
  than the one who saw the thinner image (means of
  2.2 vs 1.4).
• Four other studies confirmed this anchoring
  (reassurance?) effect.

Sticking overweight images on the fridge door may
have a reverse effect, shifting the idea of what
is normal.

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CONTROL STRATEGIES

• Many behavioural tips for controlling food
  purchase and consumption have been offered
• (1) Dont buy jumbo packs, multi-buy offers,
  snacks/sweets, meal-deals.
• (2) Store tempting foods well-packaged out of
  sight/reach (not in office drawer or glove box of
  car).
• (3) Keep a healthy option to hand
• (fruit or unsalted nuts).
• (4) Drink water rather than fizzy and sugary
  drinks.
• (5) Decide serving size in advance.
• (6) Take your time when eating.
• (7) Dont eat while doing other things
• Frequent use of such strategies discriminates
  normal from overweight people but not overweight
  from obese (Poelman et al, 2013).

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SELF-MONITORING

• A key element in behavioural weight management
  programmes is some form of recording of eating
  patterns, weight or exercise (e.g., weighing self
  first thing every morning, or regular waist
  measurement).
• Paper diaries, websites and phone aps can be
  helpful.
• Does not seem to matter exactly what is
  monitored provided it is done on a regular basis
  (Burke et al, 2011).
• Motivational, and may detect patterns, giving
  early warning.

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SLIMMING GROUPS

• Slimming classes like Weight Watchers are more
  successful than individual weight-loss programmes
  set up by doctors (Pinto et al, 2013).
• These are behaviourally oriented focus on
  changing eating habits and promoting exercise.
• Usually led by trained peer counsellors who have
  achieved their own weight loss.
• Social context contributes to motivation and
  makes the treatment affordable.

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ANOREXIA

• Pathological dieting, combined with denial of
  any problem.
• Most common in young women aged 12-19 (10x F/M).
  
• Become fearful of fat, obsessed by
  food/calories, develop rituals around
  eating/mealtimes and avoid food deceitfully
  (e.g., pushing food around plate and hiding it in
  napkin).
• Some follow pro-anorexia websites and smoke/take
  drugs rather than eat.
• May be maintained by endorphin highs evoked by
  starvation (Brindisi Rigaud, 2011).
• Can be life-threatening highest mortality of
  any mental illness (5-10 for every decade
  untreated). However, most (50-70) get better
  within 2ys.
• .

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BODY IMAGE DISTORTION

• Anorexics overestimate their size. See
  themselves as fat (or claim to so as to justify
  food-avoidance?)
• Asked to adjust a mirror until the reflection is
  accurate they make themselves fatter than they
  really are.
• May turn sideways to go through a doorway they
  would comfortably fit head-on.
• Misperception applies specifically to
  themselves, not to others around them (Guardia et
  al, 2012).
• If not thinking themselves fat, may be proud of
  their bony form, believing themselves to be
  attractive.

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RETREAT FROM PUBERTY

• Anorexia is strongly associated with onset of
  puberty (which gets earlier). Trigger may be
  observation of bodily changes like breast hip
  enlargement, which arouse fear they are getting
  fat.
• A more psychoanalytic idea is that anorexia is
  specifically focused on avoidance of menstruation
  and a fear of growing up and assuming adult
  responsibilities. Carbohydrate intake seems
  geared to keep weight just below the level where
  cycle would commence.
• Recovering anorexics who regain normal
  luteinising hormone responses to LHRF show
  greater adolescent conflict on a repertory grid
  measure (Miles Wright, 2011).

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PERSONALITY AND ANOREXIA

• A particular set of personality traits is
  associated with anorexia (introversion, anxiety,
  perfectionism, OCD). Often pride themselves in
  self-control.
• A connection with autistic spectrum disorders
  has been suggested (female Aspergers).
• Some of these associations diminish with
  recovery, so may be a result of the starvation
  effects on the brain rather than pre-existing
  causes of the disorder (Cassin von Ranson
  (2005).

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THE ANOREXIC BRAIN

• When people look at body images, input is via
  the medial occipital area (mOC), then the
  fusiform body area (FBA) to the extrastriate body
  area (EBA). Suchan et al (2013) found a lower
  density of neurons in the EBA in anorexic
  patients and reduced input from FBA. This
  weakened connectivity between FBA and EBA might
  account for the development of anorexia, or could
  be a result of it.
• Other studies have shown increased activity in
  emotional brain centres in response to food and
  body stimuli relative to controls (Zhu et al,
  2012).

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SPRING BIRTH

• Anorexia is more common in those born March to
  June (Northern Hemisphere). A similar
  relationship applies for major depression.
• Probably due to vitamin D deficiency in the
  mother during winter gestation. Allen et al
  (2013) found Australian mothers with low vitamin
  D (measured at 18 wks pregnant) were more likely
  to have teenage daughters with eating disorders.

Data from meta-analysis of 4 UK cohorts, N 1293
anorexics (Disanto et al 2011).
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MANOREXIA

• Concern with muscularity may be a male
  equivalent of female anorexia.
• Field et at (2013) found 9.2 of male
  adolescents had high concerns re muscularity
  (only 2.5 concerned about thinness).
• Often leads to use of supplements (e.g. growth
  hormone, steroids) harmful to health.
• Those concerned with thinness more prone to
  depression than those with muscularity concerns.
• Body image problems in general more common in
  homosexual men.

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BULIMIA

• Binge eating of high calorie food is followed by
  purging or self-induced vomiting.
• Stomach acids can damage throat, cause tooth
  decay bad breath. Also more common in young
  women but weight likely to be normal (Princess
  Diana).
• Men not immune (John Prescott, Elton John).
• Whereas anorexia goes with anxiety and
  constraint, bulimia relates to impaired
  self-regulation and impulse control (Marsh et al,
  2009). Comorbid with borderline personality
  disorder, substance abuse, shoplifting,
  self-mutilation and sexual disinhibition.

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TREATMENT

• May be necessary at first to hospitalise and
  force-feed.
• CBT (modification of beliefs attitudes) is
  favoured treatment but co-operation not always
  forthcoming.
• Important to look at motivation and ensure
  readiness to change.
• May need to treat co-occurring problems such as
  anxiety, perfectionism, depression, substance
  abuse and attention deficit.
• Drugs (e.g. SSRIs) may help, especially if
  depression is involved.
• Some experimental work with deep brain
  stimulation, but this is a last resort.
• The Maudsley Model (Le Grange, 2005) involves
  the family in treatment, e.g., teaching parents
  how to supervise meals. However, family attitudes
  are sometimes part of the problem.

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FAD DIETS

• Diet plans are a major industry.
• Usually work by excluding certain types of food,
  thus reducing total calories if maintained
  long-term (Pagoto Appelhans, 2013).
• Intermittent fasting also limits calorie intake,
  unless there is catch-up.
• Compliance is poor because hunger increases and
  body goes into distress mode (release of stress
  hormones and lowered metabolism). When the diet
  stops there is rapid rebound to baseline or
  beyond.
• Mostly unhealthy compared with balanced diets
  and exercise.
• Breatharianism (living only on nutrients of sun
  and air) is most effective but eventually fatal.

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SKINNY MODELS

• Models in womens magazines are often airbrushed
  and unrealistic. Catwalk models are pressured to
  be dangerously thin so as not to distract from
  the clothes.
• Proliferation of unhealthily thin models in the
  media has been linked to body dissatisfaction,
  substance abuse (smoking/heroin), eating
  disorders and depression (Grabe et al, 2008).
• However, only women high in neuroticism suffer
  harmful effects of thin models (Roberts Good,
  2010).
• Long exposure to thin-ideals can sometimes
  increase body satisfaction by prompting dieting
  and exercise (Knoblock-Westerwick Crane, 2012).

If Barbie were real she would have a 16in waist
and be infertile.
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HELP FOR THIN WOMEN