obesity matt jarvis. obesity why is obesity a concern? obesity is an excess of body fat that is...
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Obesity
Matt Jarvis
Obesity
Why is obesity a concern?
• Obesity is an excess of body fat that is
associated with risks to health.
• It is associated with a higher risk of
diabetes, heart disease and cancer.
Obesity is much more common now than in the past.Three in four UK adults carry too much fat.
Obesity
Why has obesity increased?
The obesogenic environment is believed to be the main factor.
This is an environment containing many tasty high-calorie foods.
Factors in the obesogenic
environment include:
• Larger portion sizes
• Marketing of unhealthy foods
• Cheaper energy-rich food
Obesity
Genetic influences on weight
It is apparent that not everyone is overweight in spite of the
obesogenic environment. This suggests there are genetic
differences in how we respond to food.
Twin studies
Identical twins are much more similar in weight than non-
identical twins. This suggests weight is largely genetically
controlled.
Obesity
Genetic risk of obesity
Several genetic variations have been identified that are
associated with weight. The first was the FTO gene.
The high-risk FTO
gene carries a 50%
increased risk of
obesity
Several other risk-genes have
been identified. The more of
these we have the more likely
we are to be obese
Obesity
Inherited behavioural risk
Two major factors have been identified:
• Food responsiveness: some people are more
tempted by food-cues so are more likely to indulge
• Satiety signalling: some people do not realise
they are full and so tend to over-eat
Obesity
Conclusions
• Both genetic and environmental influences impact on obesity.
• Where the environment is rich in high-energy food, obesity
levels will probably always be high.
• Some individuals are particularly susceptible to the
temptation to over-eat as a result of their genetic make-up.
• Some individuals are particularly vulnerable to over-eating as
they do not respond to fullness as a result of their genetic
make-up.
• There are a range of strategies to limit over-eating.
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