Depends how tall you are. Usually you work out what’s called Body Mass Index (BMI) from someone’s height and weight, and if that’s over 30 a person usually gets classed as obese. http://en.wikipedia.org/wiki/Body_mass_index
BMI is only a rough guide to obesity, as it is possible to be really fit (like a weightlifter or boxer) and be classed as obese. This is because muscles are denser than fat and so weigh more.
Yes, what Kirsty said – the standard NHS line is “Interpret BMI with caution in very muscular adults, as it is a less accurate measure of adiposity in this group”, specifically because muscles are denser than fat. But BMI is still useful, as it ‘controls’ for your height – and I’d guess there aren’t usually that many super-fit muscular adults in the groups of people whose weight we’d typically be worrying about.
Anyway, take home message, while BMI needs interpreting with caution, if someone scores > 30 then their weight is a worry, and they’d probably be classified as obese unless they are a rugby player who lifts weights every day.
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Austin commented on :
Yes, what Kirsty said – the standard NHS line is “Interpret BMI with caution in very muscular adults, as it is a less accurate measure of adiposity in this group”, specifically because muscles are denser than fat. But BMI is still useful, as it ‘controls’ for your height – and I’d guess there aren’t usually that many super-fit muscular adults in the groups of people whose weight we’d typically be worrying about.
Anyway, take home message, while BMI needs interpreting with caution, if someone scores > 30 then their weight is a worry, and they’d probably be classified as obese unless they are a rugby player who lifts weights every day.