Obesity

Obesity is when a person is carrying too much body fat for their height and sex. A person is considered obese if they have a Body Mass Index (BMI) - weight in kilograms divided by their height in metres squared - of 30 or greater. Obesity can happen when you eat more calories than you burn off over a period of time.

The rate at which you burn off calories from food and drink is known as your metabolic rate. This is often faster during growth spurts and puberty, but reaches a fairly steady rate by adulthood.

According to figures from the National Audit Office, being obese can take up to nine years off your lifespan. It also makes you far more likely to develop a range of health-related problems, including:

diabetes,
heart disease
stroke,
osteoarthritis,
high blood pressure

gallstones,
infertility, and
depression.

Combined with a lack of exercise, obesity contributes to one third of cancers of the colon, breast, kidney and stomach.