An obesity epidemic is costing the NHS in England at least £480m a year, with costs to the wider economy probably in excess of £2bn, the National Audit Office has revealed.
Obesity rates nearly trebled between 1980 and 1998 (the most recent year for which figures are available) and there is no sign that the upward trend has peaked.
Nearly two-thirds of men and over half of women are overweight or obese; 21 per cent of women, and 17 per cent of men are obese, defined as a body mass index of over 30. The NAO report points out that if the current trend continues then England will match US obesity levels by 2010.
The NAO's examination of national and international data suggests that obesity was responsible for 30,000 premature deaths in England in 1998, as well as 18 million days of sickness absence.
'It is an epidemic with very extensive human consequences. The killer fact is that, on average, obesity leads to nine years' shorter lifespan for those who die of it, ' said NAO director James Robertson. He emphasised that the report's estimates of the financial costs of treating obesity were 'conservative'.
Studies of countries with a similar obesity prevalence to England's have estimated direct costs at between 2 and 6 per cent of national healthcare budgets - equivalent to NHS costs of between£700m-£2.1bn in 1998.
Virtually all obese people develop symptoms of ill-health by the age of 40, and the majority develop diseases that require medical intervention before they are 60, says the report. The 'big three' cost-drivers are hypertension, coronary heart disease, and type-2 diabetes.
The NAO found that the NHS's efforts to help people lose excess weight were 'patchy'. Its survey of health authorities in 1999 found that 83 per cent had identified obesity as a public health risk in their health improvement programme, but only 28 per cent had taken action.
The report's survey of 1,200 GPs found widespread uncertainty about the different interventions; 64 per cent believed the treatments available to them were 'of little or no effectiveness'.
The report recommends that local strategies take account of the Health Development Agency's guidance on effective interventions and that HAs set 'realistic' targets for improving diet, promoting physical activity and halting the rising trends in the prevalence of overweight and obesity.
The report also says that the Department of Health should commission an appraisal of the effectiveness of treatments within general practices and in secondary care; build on the national framework for coronary heart disease and clarify the responsibilities of GPs to identify people at risk from excess weight calls; liaise with the National Institute for Clinical Excellence to disseminate guidelines for managing overweight and obese people in general practice.
It also calls on the DoH to establish a cross-departmental advisory group to co-ordinate all government research on the treatment and prevention of obesity.