What is obesity?

Obesity is a condition in which excess fat leads to impairments in health. It's usually defined as a Body Mass Index (BMI) greater than 30 kg/m² where excess weight is gained due to energy intake exceeding energy expenditure.

Risks

Both being obese and being overweight increase the risk of a range of diseases that can have a significant health impact on individuals.
The risks are higher as BMI increases for

• diabetes - the risk of developing type 2 diabetes is about 20 times greater for people who are very obese compared with healthy weight individuals.
• cancer - 10 per cent of all cancer deaths among non-smokers are related to obesity.
• coronary heart disease - leading to heart attack and stroke
• hypertension - 85 per cent of hypertension is associated with a BMI greater than 25.
• liver disease - up to 90 per cent of people who are obese have fatty liver which may lead to cirrhosis.

Causes of obesity

Genetics

It may be that our genes make us more likely to gain weight. Even children adopted at birth tend to resemble their biological rather than adoptive parents. But it's not known exactly which genes are involved or how they work. Some people who gain weight easily may find that they're less sensitive to the body's message of fullness and therefore continue to eat even when full.

Eating behaviour

How we feel can affect how we eat and some people eat and drink more when they're stressed, depressed or anxious. Others eat more when they're bored or tired which can result in an excess of calories being consumed, without the person always being aware of having eaten these extra calories.

Activity

It's important to recognise the links between physical activity, exercise and health. Individuals and families alike must take responsibility for increasing the amount of physical activity undertaken in everyday life, especially for children, in order to stay healthy. Government, businesses, local communities and other organisations must support this by creating environments where walking, cycling and other forms of physical activity, exercise and sport are accessible, safe and the norm.