While it is the 'most preventable' cause of ill health, the Office of Health Economics (OHE) says that it costs pounds 30m to treat obesity alone but another pounds 165.5m through the contribution obesity makes to strokes, heart disease, diabetes, arthritis and other diseases.
At the same time, Britons pay pounds 80m a year for non-prescription products in the form of replacement meals, another pounds 5.5m on slimming magazines and an untold figure on other slimming products.
Richard West, research associate at the OHE, says in the report that obese people can also expect to pay more for life insurance.
A separate study of nearly 1,000 GPs in Northern Ireland, published last week, found one in five said that they would give obese people lower priority even when their medical needs were the same as a slimmer patient's.
The report from the OHE, a research body founded by the Association of the British Pharmaceutical Industry, says: 'Medical personnel contribute to making fatness a social handicap . . . Some doctors perceived fat people as weak-willed, ugly and awkward.'
Mr West says the profile of obesity must be raised among health professionals if the increase in obesity is to be stemmed.
'We are currently witnessing an upward trend in the prevalence of obesity, with over half of the male population and two in five women being overweight,' the report said.
'An estimated 20 million adults in the UK are overweight, with six million of these being obese.'
Recent data revealed that the number of people calculated as obese - at least 20 per cent more than the ideal weight for height - has risen by over 50 per cent among men since 1986-87 and by 25 per cent among women.
The report says the cost of treating obesity in the NHS is pounds 13.8m for general practice; pounds 8.3m for in- patients; pounds 850,000 in out-patients; pounds 2.9m for pharmaceutical services and pounds 3.5m for dieticians.
The other costs are calculated by taking the known cost of, for instance, stroke at pounds 550m and assuming that 'a conservative 5 per cent' of strokes result from obesity, giving a cost of pounds 27.5m. Similarly the cost for heart attacks is pounds 7.5m; diabetes pounds 100m and arthritis pounds 30m.
But obesity is no longer a condition of the rich. One survey of 5,362 people shows that men and women in manual and non-skilled social classes were significantly more likely to be overweight by the age of 36 than non-manual workers.
Reduced calorie diets for most overweight people are recommended, together with a change in eating habits to provide more fresh fruit and vegetables and less sugar and animal fat.
For the severely obese, very low calorie diets for short periods, anorectic drugs or surgery including jaw wiring are available.
Obesity; Office of Health Economics, 12 Whitehall, London SW1A 2DY; pounds 7.50.