Transcript Factors affecting attitudes to food and eating behaviour

Eating Behaviour
 There
are many factors shown to influence
our attitudes to food. These include:
 innate/evolutionary influences,
 early learning experience
 familiarity,
 neophobia,
 Parental attitudes,
 weight concern,
 cultural factors,
 the food industry etc.
 Many
factors
influence our diet –
psychological, social,
cultural – showing
that despite feeding
behaviour having
basic biological
functions, it can be
modified by many
other influences.
 Babies
are born with
taste receptors for
sweet, sour, salt,
bitter and umami
taste qualities.
 This means that they
can identify and
distinguish between
foods from an early
age.
 They
like sweet tastes
– and sweet foods
even reduce distress
in babies. (Benton,
2002).
 This suggests that we
have innate
preferences for foods
that are genetically
programmed.
 Widespread
in the
animal kingdom as a
basic survival
mechanism (avoids
poisoning).
 Neophobia is also
found in babies and
children although it
decreases with age.
 Experience
and familiarity increase food
preferences.
 Birch and Marlin (1982) found that
exposure of 2 year-olds to a new food
over 6 weeks increased preference for
that food, a minimum of 8 – 10 exposures
was necessary for the initial dislike
(neophobia) to change to a preference.
 Children learn that food is safe.
The mother’s attitude to food is a strong influence
on the child’s preferences.
 If the mother is aware of health issues she will
work harder to make sure her child has a
balanced diet.
 If the mother is less aware or less concerned
over health issues such as obesity, she will take
less care over the child’s diet.
 There is a significant correlation between the
diets of mothers and children (Ogden, 2007).
 Parents, especially mothers provide key role
models for the child.

Once the child reaches school, peers become
important. Studies have shown that modelling
using admired peers can increase consumption
of fruit and vegetables (Lowe, Dowey and Horne,
1998).
 Throughout childhood children are also exposed
to widespread food advertising on television,
using peer models, animations etc. to make food
seem more attractive. This can be effective in
developing preferences, but unfortunately
advertised foods tend to be high in fat and
carbohydrates, probably contributing to
problems such as childhood obesity.

Used by many parents and based on operant
conditioning, rewards consumption of a dislike
food with a desired food –
 ‘You can have some ice cream if you eat your
vegetables’. Unfortunately studies have shown
that while this technique may work in the short
term it increases the desirability of the reward
food and decreases liking for the non-preferred
food (Ogden, 2007; Birch 1999). Similarly,
punishing poor eating habits by denying access
to a desired food simply increases the
preferences for the desired food.

 Based
in France
 This study collected data between 1982
and 1999 on the food preferences of
children aged 2 – 3 at nurseries.
 Children were allowed free choice of a
variety of foods and these preferences
were recorded.
 In 2002 the children and parents were
contacted and invited to take part in a
follow-up study.
 Correlations
between food preferences at
age 2-3 and at ages 4 – 7 were significant.
 Correlations at later ages were not
significant.
 Preferences for cheese and, to a lesser
extent, vegetables, remained fairly stable
between ages 2 – 3 and 17 -22.
 There was some increase in preference for
vegetables with increasing age.
 There were decreases in preference for
meat products in females as they got older,
but this remained fairly stable in males.
Preferences in adolescence and early adulthood
become influenced by exposure, for example to
vegetables.
 There may also be ethical concerns over killing and
eating animals and health concerns (less meat and
more vegetables) especially in females.
 This supports a role for psychological, social and
cultural factors in influencing food preferences in
adolescence and early adulthood.
 However, individual preferences at later ages were
related to preferences at age 2 – 3, especially for
cheese, and around 50% of foods in other categories,
showing the importance of early experience.


Food preferences at 2-3 years old were recorded
from actual choices, but the follow-up study had
to use questionnaires and interviews. These may
not provide a completely accurate picture of food
preferences, as participants may feel a need to
present a ‘healthier’ view in their answers. Foods
were also categorised into groups, so some data
on individual foods might be lost. However, the
results support previous research on the role of
familiarity and social/cultural variables on food
preferences.
 Attitudes to health
 In the Western world
there is increasing
concern over diet and health.
 Obesity is increasing, along with its
associated risks of heart disease and
diabetes.
 There is growing awareness of the need for
diets that are less fatty and include more
fruit and vegetables, and this has led to
many adults altering attitudes to food and
changing their diets and those of their
children (Ogden, 2007).
 Mothers
dissatisfied with their body size
or shape can pass this concern on to their
daughters, affecting the girl’s attitude to
food and feeding.
 This can lead to eating disorders.
 Parents
who are aware of the health
consequences of poor diets may try to
change the family’s eating habits.
However, this depends on the knowledge
of healthy diets, the motivation to change,
and the time and perhaps the financial
resources to put the changes into effect.
Those higher up the socio-economic
scale are more likely to be aware of
healthy diets and try to follow them.
 The
TV chef Jamie Oliver began a campaign
in 2007 to improve the diets of young
children and their parents, but the slow
progress of this campaign shows how hard it
is to shift established attitudes to food. In an
age when both parents may be working, the
availability of cheap fast food that is quick to
prepare and easy to eat in front of the TV is
a major problem in changing attitudes to
food.
 Food
has many other functions besides
dietary ones, e.g. Religious functions.
 Special meals on certain festivals, or
ceremonial banquets at weddings.
Providing meals can be an expression of
love and caring, and the vast number of
recipe books and TV cookery programmes
shows the widespread interest in food and
preparing meals. However, a key area
concerns the emotional aspects of food and
feeding behaviour.
 Hunger
is associated with increased arousal,
vigilance and irritability, while after a meal
we feel calm and sleepy. More strikingly,
studies have shown that people who are
stressed or depressed increase the
carbohydrate (especially sugar) and fat
content of their meals (Gibson, 2006). This
change is associated with better mood and
more energy.
 We also know that most people find sweet
tastes (as in carbohydrates like sugar)
pleasurable.
 The serotonin hypothesis:
 Carbs such as chocolate contain
the amino
acid tryptophan.
 This is used by the brain in the manufacture
of the neurotransmitter serotonin. Low levels
of serotonin are associated with depression
and it has been proposed that people with
stress or depression take in more carbs
because it leads to increased levels of
serotonin in the brain. This reduces their
depression (Gibson, 2006).
 This
increase in serotonin only occurs
when we take in pure carbohydrates,
which is extremely rare. The presence of
even a small amount of protein, as in
chocolate, prevents the tryptophan
entering the brain and so serotonin levels
will not change (Benton, 2002). The
serotonin hypothesis is unlikely to
explain the antidepressant effects of high
carb diets.
In the brain there are also opiate (or opioid)
neurotransmitters.
 Two examples are enkephalin and beta-endorphin.
They are released from neurons and act at synapses
with opiate receptors. As their name suggests,
opiates (endorphins) are chemically very similar to
the drug heroin. Heroin acts on these brain opiate
pathways. Heroin is a highly addictive drug which
can also produce pleasurable feelings and euphoria.
Therefore, it seems likely that the brain’s opiate
pathways are part of our reward system, a network of
pathways that control our feeling of pleasure and
reward.

 Is
activated by natural rewards such as
food and drink.
 If the rewarding properties of food
depend upon the opiate/endorphin
system, then we would expect some
interaction between opiates and feeding
behaviour.
 This is what we find (Grigson, 2002;
Gibson, 2006)
 Opiate
drugs increase food intake and
increase the perceived tastiness of food.
 Blocking the endorphin system with the
drug nalaxone reduces food intake,
especially in sweet foods, and
suppresses thoughts about food. This
shows that the system is involved in the
feeding regulation.
 Sweet foods increase the release of
endorphins in the brain.
 We
feel better after eating sweet
carbohydrates as these foods in
particular activate our natural reward
pathways.
 This effect would be more obvious in
people with depression or those highly
stressed, but even in normal
circumstances sweet foods can improve
mood.
 We
are very efficient at learning
associations between taste and
consequences (e.g. Taste aversion
learning).
 This applies to positive effects as well – we
learn to associate the mood-improving
effects of carbs, especially sugars, with the
sweet taste. So when we taste the food we
have expectations about the consequences,
and this applies to physiological systems as
well.
 Glucose
reliably improves performance
on cognitive tasks. However, if people are
given a glucose drink but are told it is a
placebo (an inactive solution with no
glucose), then the effect disappears. Our
expectations override the actual intake of
glucose.
 The
sweet taste of a glucose solution
immediately produces a release of insulin
from the pancreas gland, anticipating a rise
in blood glucose levels. This happens even
with drinks sweetened with saccharine, a
compound that is not processed by the
body. However, we have learnt that sweet
tastes usually mean glucose, so our body
prepares itself. Anticipation and expectation
on the basis of learning and experiences
are vital parts of our feeding behaviour
(Gibson, 2006).
 In
some parts of the world, food is scarce
and there are high levels of malnutrition
and starvation. A second major effect of
culture is the availability of different
types of food. Eskimos live largely on
seal meat because that is what is
available.
 Although
the globalisation of the food
market means that even in remote
communities food choice is increasing, at
least in the sense that fast food is now
available worldwide, differences are still
found.
 Wardle et al, (1997) surveyed the diets of
16,000 young adults across 21 European
countries. In general the number eating a
basic and healthy diet was low, with females
doing better than males.
 People
in Sweden, Norway, Denmark and
Holland eat the most fibre; and those in
Portugal, Spain and Italy eat the least
fibre.
 People in Italy, Portugal and Spain eat the
most fruit, and those in England and
Scotland eat the least.
 People in Poland and Portugal have the
highest salt intake, and those in Sweden
and Finland have the lowest intake.
People in these countries seem to have lower levels
of heart disease and obesity than in other European
countries.
 Key differences are:
 Use of olive oil (the fat in olive oil is unsaturated and
thought to be healthier than saturated animal fats
widely used in the UK.
 High levels of fruit and vegetables
 Moderate levels of cheese and other dairy products
 Moderate levels of fish and poultry
 Low levels of red meat
 Low to moderate intake of wine.
 In general, lower levels of processed foods and more
natural products are used.

 Cultural
differences are being reduced
with the spread of highly processed fast
foods with high saturated fat content.
 Exposure of ethnic groups to new diets
can have dramatic effects.
 Studies
on the Pica Indians of New
Mexico show that those who stay in their
communities have low levels of obesity.
 Whereas those who move areas are
heavily influenced by American culture
and diet and develop high levels of
obesity.
 On
the other hand, a series of studies by
Leshem shows the persistence of cultural
effects on diet.
 He compared Bedouin Arab women
living in desert encampments with
Bedouin Arab women who had lived for
at least a generation in an urban setting.
He compared both with a group of Jewish
women also living in an urban
environment.
 The
diet of urban Bedouins was hardly
different from that of desert Beouins, with
both groups differing significantly from the
Jewish women.
 Bedouin groups had a much higher intake of
energy, especially carbs and proteins.
 The Bedouin groups had significantly
higher levels of salt intake (associated with
the high fluid and salt loss as a result of
living in the desert).
 This
adaptation survives the move to an
urban community with easy access to a
range of foods.
 Compared
diets of ethnic communities
living close to each other in Israel with
equal access to shops and food.
 In the Muslim community the intake of
carbs was twice that of the Christian
group, and they also took in higher levels
of proteins, fats and salt although the
mean average body mass index was
virtually identical.
 Cultural
differences on diet are profound
and persist even where there is equal
access to the same foods.
 These differences may originate in
adaptations to previous environments, as
with salt intake in the Bedouin people.
 In some groups there are strict religious
guidelines on what may or may not be
eaten, and these will survive whatever
the surrounding environment.
 Diet
can show clear cultural variations , as
Leshem’s work demonstrates. However, we
cannot conclude that these are
environmental or ‘nurture’ effects rather
than inherited tendencies (‘nature’). Where
groups such as the Beduoin have lived in the
same environment for may generations, it
may be that their diet today is a mixture of
innate (genetic) factors and culturally
transmitted preferences (nurture).
A
wide range of factors influence our
attitudes to food and our eating behaviour,
and it is impossible to say which ones are
most important. You need to be aware of the
different factors and the relevant evidence.
Most importantly, you need to be aware that
eating behaviour depends on early
experience and learning, media, family and
cultural influences, but also our biological
requirements for a balanced diet.