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Obesity - Background information
What is it?
- The terms 'overweight' and 'obesity' are used to describe excess body fatness which can affect a person's health and well being [National Heart Forum, 2007].
- The National Institute for Health and Clinical Excellence classify degrees of overweight and obesity according to a person's body mass index (BMI) [NICE, 2006b]:
- Overweight — BMI of 25–29.9 kg/m2.
- Obesity l — BMI of 30–34.9 kg/m2.
- Obesity ll — BMI of 35–39.9 kg/m2.
- Obesity lll — BMI of greater than or equal to 40 kg/m2.
- BMI should be interpreted with caution as it is not a direct measure of adiposity (e.g. in adults who are very muscular, it is a less accurate measure of fatness) [NICE, 2006b].
- Calculate the person's BMI by dividing their weight in kilograms by the square of their height in metres [Warrell et al, 2003]. An online calculator is available at www.nhs.uk.
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