Tackling Obesity in England - National Audit Office

TACKLING OBESITY IN ENGLANDPart 2The prevalence and costs of obesityin EnglandA standard definition of obesity2.1 Obesity is most commonly defined by clinicians interms of the body mass index (BMI). The BMI iscalculated as follows:Weight in kilogrammes = BMI(Height in metres) 22.2 A desirable body mass index is considered to be in theregion 20 to 25. Anything above this is defined as'overweight', and a BMI over 30 is defined as 'obese'.Figure 3 illustrates the range of BMI classifications andAppendix 2 provides further details.2.3 The health hazards of obesity are compounded by theinfluence of fat which is distributed around the waist,more typical of obese men than women. For this reason,the waist circumference and waist-hip ratio are alsoused to assess the risks associated with obesity. Thoughthere is no consensus about the cut off points that defineobesity using these indicators, a report by the WorldHealth Organization 10 suggests that increased risk ispresent when the waist circumference exceeds 94 cm(37 inches) for men or 80 cm (32 inches) for women.About a fifth of the population isobese and nearly two thirds of menand over half of women in Englandare either overweight or obese2.4 In 1998, the year for which most recent figures areavailable, 19 per cent of adults in England were obese,with a BMI over 30 1 . More women than men wereobese - 21 per cent of women compared to 17 per centof men. But more men than women were in theoverweight category (BMI between 25 and 30) -46 per cent compared to 32 per cent. Combining theoverweight and obese groups, in 1998 nearly two thirdsof men and just over half of women were eitheroverweight or obese.3Different categories of weight defined by Body Mass Index (kg/m 2 )125115105Morbidly Obese95Weight (kg)8575ObeseOverweightHealthy65Underweight5545part twoHeight (metres)Source: National Audit Office based on classifications used in the Health Survey for England 111