The causes of obesity are
many and varied but they all boil down one thing; taking in more energy in food
and drink than you use up in daily activities. This means that the only way to
avoid obesity and to maintain a normal healthy weight throughout life is to eat
less but move more. This is, however, easier said than done.
As people in
industrialised societies have moved from an active lifestyle in which they did
regular, hard and physical work to having more sedentary occupations, their
energy needs have reduced. But that does not mean that we necessarily eat less
– in fact, increased consumption of highly processed foods rich in fat and
sugar that make up fast foods, ready meals and convenience foods means that our
energy intake has risen. This imbalance is one of the fundamental causes of
Of course, why the
imbalance arises is very complex; the underlying causes of obesity are due to
many different factors, some cultural, some genetic and some behavioural.
Cultural causes of obesity
Most human cultures put
food at the centre of their social interactions. Groups and families from all
different parts of the world gather together to eat meals, whether it is a
royal banquet for 300 people, a ritual tribal feast or a small family
breakfast. Eating and sharing food is a pleasure and can help maintain and
strengthen the bonds that hold relationships together. Research has shown that
this type of communal eating is a very positive experience and, interestingly,
people generally eat much less in a group then they do when eating alone. The
cultural causes of obesity stem from activities within human societies that use
food for some other purpose.
One of the major causes of
obesity, particularly in women in our society, is comfort eating. We become
dependent on food as something to improve mood and as a way of coping with
problems. Once the link between food and hunger is replaced by an association
between food and feeling OK, whether you are hungry or not, eating can spiral
out of control.
The fact that food is big
business in the western world is another of the major cultural causes of
obesity. In the Britain of the 1940s, there was very little choice of food. Fresh
meat, vegetables, flour, sugar, eggs, cheese, some cereals, fresh fruit and
vegetables made up the vast majority of everyone’s diet and there were hardly
any convenience foods. The overall diet that people ate was generally very
healthy although this was regarded as a time of austerity and some people
undoubtedly did not have enough food.
Studies show that people
tend to eat less when fewer foods are available but today, with supermarkets
stacked high with thousands of different products, we have a much wider choice
and we tend to eat more of a greater variety of foods. This hasn’t made our
diet more balanced in the nutritional sense because it is now higher in fat and
sugar and lower in the fresh foods that provide vitamins and minerals. Some
experts believe that this greater variety could be one of the more subtle
causes of obesity; it over-stimulates our palate, encouraging us to over-eat on
a daily basis.
Genetic causes of obesity
Several key genes have
been implicated as genetic causes of obesity but taking a more overall perspective,
it should be no surprise that humans face such a battle with maintaining a
sensible weight in modern society. Humans have evolved to be hunters and
gatherers. We originally spent a lot of energy obtaining an unpredictable
supply of just enough food to survive. The human system is geared up to feast
in times of plenty to store up fat to survive the leaner periods when food is
scarce. In an environment where there is always plenty of food, the body’s
natural reflex is still to eat in case the supply runs out. Our evolution could
be one of the key causes of obesity that will be very difficult to overcome.
The specific genetic
information certainly paints a very complex picture. Some people have a mix of
genes that makes them more likely to become obese but other people seem to have
no apparently abnormal genes but they become exceptionally obese. Some mixtures
of genes may cause people to metabolise food differently, or genetics may make
a difference to the way they feel hunger or, more importantly, the way they
feel full after eating. More studies may eventually unravel the complex
processes involved and may pinpoint the exact genetic causes of obesity.
Research may also lead to better treatments for extreme forms of obesity in the
Behavioural causes of obesity
With genetics and culture
already tending to make us overeat and gain weight, our behaviour can tip us
over the edge. If we choose to buy high energy foods and opt to do as little
exercise as possible, obesity is almost inevitable.
The behaviour that we
choose is often a result of our parents and our friends and peers. People whose
parents are obese have a much greater chance of becoming overweight themselves.
The culture of binge drinking and regular drinking in the UK is also one of the
major behavioural causes of obesity. Alcohol has to be broken down by the liver
and, although it contains a lot of calories, it has few nutrients. Drinking
large amounts on a regular basis adds to the imbalance between energy intake
and the energy used up.
Stress, pressure at work,
giving up smoking can all make comfort eating more likely and feeling depressed
or having low self esteem also makes people feel less able to take part in
sports or other activities that involved physical exercise. Taking too little
exercise, even if you eat sensibly, is another of the major behavioural causes
Tackling the causes of obesity
Many medical experts and
people in government realise that obesity is a major threat to the health of
the population in general. Obesity can lead to a far higher risk of major
chronic and potentially fatal diseases such as heart disease, strokes,
diabetes, some types of cancer and arthritis.
It is much more difficult
to know exactly how to approach the causes of obesity to make a radical
difference for the future. Better education is one method and schools are
putting in place many different programs to encourage children to start eating
more healthy food and to learn to love doing exercise and sport – but doing
enough to combat all the different causes of obesity is likely to be a great