Yesterday's copy of The Irish Times contained a number of advertisements featuring women, all young, all good-looking and none of them larger than a size 10. The products they were promoting tended to be associated with financial services and certainly had nothing to do with fashion.

And yet, whenever the problem of eating disorders comes up for discussion, the fashion industry is held to be primarily responsible for disseminating the impossibly ideal images of women which have led to suffering among so many teenage girls and young women. Fashion, it would seem, must admit responsibility for eating disorders.

Fashion is an easy target, of course, and frequently a willing one, because the business is so self-regarding that it considers any attention, even blame, preferable to being ignored. This helps to explain why, earlier this week, the editors of Britain's fashion magazines, having attended a government-initiated Body Image summit, were reported as agreeing to adopt a code under which they will refuse to use "unhealthily thin" models and monitor the shape of women who appear in their publications.

But one of those editors, Alexandra Shulman of Vogue, had quite correctly pointed out earlier that anorexia nervosa and bulimia are not diseases which can be caught from the pages of her magazine. And how is "unhealthily thin" to be defined? Most models are taller and thinner than the average woman, who today is likely to be a size 16, not 10. The probability of the larger size appearing within the covers of Vogue, or any other fashion magazine, is remote. In any case, this is largely a matter of scapegoating, even if the goat has, in this instance, groomed itself for the role. Yes, the fashion industry has to take some responsibility for the obsession with thinness which has led to widespread dissatisfaction among women with their body shapes. Designers, for example, tend to create clothes which look best on tall, thin models; when these items are made in larger sizes, they lose much of their appeal.

But fashion is a commercial business responding to the demands of the market and it is the latter which dictates what must be considered the ideal body shape. This is why tall, thin models are used not just to sell clothes but almost everything else as well.

When women appear in advertising, they invariably reflect the current societal ideal and at the moment, that would appear to be a size 10 figure, along with clear skin, excellent teeth and blond hair. Whether selling the merits of washing powder or home insurance, the ideal scarcely varies and one of her key features is thinness.

It is hard to imagine - let alone find - a size 16 or 18 woman in contemporary advertising or among the myriad actors and presenters who appear on television and cinema screens. They exist, but as exceptions to the size 10 rule. The thin ideal is not exclusive to fashion; it has become universal.

In any debate on the subject of eating disorders, that universality ought to be taken into account, as should the reality that obesity is now a more serious and widespread problem. It is extraordinary that women such as actresses Calista Flockhart and Courtney Cox, who are regarded as excessively thin, may be criticised for their appearance but would not be damned were they overweight. And this is so, despite obesity now being regarded in the United States as the most significant health problem among children.

In this State, the National Nutrition Surveillance Centre's annual report last December showed 40 per cent of Irish men and 25 per cent of Irish women are overweight, and 11.6 and 9 per cent respectively are obese. The health risks associated with this condition, especially heart disease and certain forms of cancer, are well-known but do not appear to act as a deterrent against excessive eating.

Far more people in Ireland are likely to suffer the consequences of being overweight than underweight. What this information suggests is that the thin ideal, whether promoted by fashion or any other industry, bears little relation to reality. While eating disorders are obviously matters of serious concern, their origins are clearly much more complex than teenage girls looking at the fashion pages of glossy magazines.