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An obese patient is 20% or more heavier than their ideal weight.
Excess body weight is an important public health problem because it is associated with:
Obesity is graded according to the Body Mass Index (BMI):
Measures of overweight, obesity and central adiposity in adults (3)
People with a South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background are prone to central adiposity and their cardiometabolic risk occurs at lower BMI, so use lower BMI thresholds as a practical measure of overweight and obesity:
For people in these groups, obesity classes 2 and 3 are usually identified by reducing the thresholds highlighted by 2.5 kg/m2
Interpret BMI with caution in adults with high muscle mass because it may be a less accurate measure of central adiposity in this group.
Interpret BMI with caution in people aged 65 and over, taking into account comorbidities, conditions that may affect functional capacity and the possible protective effect of having a slightly higher BMI when older.
BMI in children (3):
The health benefits of modest (10%) weight loss was previously summarised by SIGN- although the precise benefits will vary in individuals depending on initial body weight, current health and degree of weight loss) (4)
By 2030 an estimated 38% of the world’s adult population will be overweight and another 20% will be obese (5)