AS SHOWN by the 46-stone Glamorgan couple banned as foster parents by their local council on grounds of obesity, seriously overweight people face many difficulties. Those who live in Western society are battered daily by images intended to convey an ideal stereotype. The message of the media, and of advertising in particular, is that all rational, healthy, normal and right- thinking people should strive to conform to these ideals. Women should be slim yet curvaceous; men tallish, muscular and, yes, slim - though since less of their body is generally on view, they will be less severely judged.

In our hearts we know these ideals are unrealistic and create considerable distress among those whose physiques are at odds with them. Yet most people find it hard not to be affected by the barrage of images. They may know it is unfair to be more favourably predisposed to the good-looking than to those deemed unprepossessing. But they cannot suppress such reactions.

A special brand of censoriousness is reserved for the seriously obese. They are held solely responsible for their condition, and for not exercising the degree of self-control supposedly needed to correct it. To make matters worse, the effect of their excessive intake of food is permanently on display, unlike the effects of heavy smoking or drinking (though the latter can contribute to overweight). Yet there is something akin to racism in the 'sizeism' or 'lookism' that condemns them, not least because obesity is often triggered not by self-indulgence but by a genetic predisposition towards it.

The doctor's letter explaining the South Glamorgan council's ruling speaks broadly of 'lifestyle in terms of the eating patterns demonstrated to a young child', of limitations to mobility, and the 'quite profound psychological disturbance' commonly associated with people with this degree of excess weight.

Ostensibly, such considerations do not seem to justify a blanket ban on fostering. At their present weight of almost 26 stone and just over 20 stone, the couple concerned may not be well suited to looking after a hyperactive three-year-old boy. But if they had the right sort of temperament they could be extremely good for an older child who needed, say, loving care, firm guidance and a sympathetic audience. There is little doubt that serious obesity reduces the expectation of life in several senses. But it is hard to see why, in principle, it should exclude success as a foster parent.