WE ARE obsessed with body weight. We are obsessed with celebrity. You would think that the most desirable thing to be in our strange world would be a fat celebrity; and it is true that Dawn French has been playing loveable for years.

But it's not easy being a fat celebrity.

Weight-gain is much more objectionable to us than evidence of cruelty, of vanity (hah! ), or of selfishness. It seems that Elvis really broke our hearts, not when he started popping speed or trying to have sex with underage girls, but when he started putting an unacceptable amount of strain on those diamante belts.

You would have thought that Fergie, God bless her, would be very popular, as she was once big . . . and not that terribly big either . . . and world-famous because she had married into the British royal family. But no. The only way Fergie could survive in the media world was by becoming a spokeswoman for the diet industry. And she looks terrible now that she is thin . . . all shinbones and jaw, and not at all like that jolly type of girl who waved out of the carriage on her wedding day.

Fat is the worst word you can say about a female in public life. Fat is seen as the chink in the armour of female achievement. Mary Lou McDonald, who is an MEP for Sinn Fein, has been having a tough time of it recently. And while I am glad that Sinn Fein representatives have been having a tough time of it, I would prefer that they were criticised for supporting a campaign of murder, intimidation and cigarette smuggling rather than have them condemned for allegedly having gained weight in Strasbourg. Yet Mary Lou was singled out by another Sunday newspaper for her calorific intake, as if it was her sedentary lifestyle that was to blame for the moral mudslide of Irish republicanism.

Plus, I met her and she looked terrific.

I am not going to drag Mary Harney into this. Her treatment at the hands of the national schoolboys is almost enough to make you vote PD. I would like to think that she has responded to years of ignorant abuse by the media in general and scumbag rugby players in particular simply by shrugging her shoulders, whispering "**** them!", before lighting a defiant cigar. But I do not actually believe this to be true.

It is little comfort to either Mary Harney or Mary Lou that such shameful attacks are unpunished examples of disgusting misogyny. Everyone knows they are designed to be deeply personal, and to make you cry. After all who . . . except me . . . keeps such a careful eye on the Taoiseach's weight?

When earnest people wonder why women do not enter politics in greater numbers they need not really spend their research grants on anything but our newspapers, and perhaps a few Babychams in the bar of the local rugby club. Women in public life, and particularly women politicians, are really hated. Next time there's a photospread of male TDs on the beach in their swimsuits, please let us know.

In Hollywood, Elizabeth Taylor was a great beauty who gained weight fast, and became a staple ingredient in other people's comedy routines. Joan Rivers . . .

anorexic genius with an obsessive love of plastic surgery . . . said that Elizabeth Taylor stood in front of her microwave hissing "Faster! Faster!". The thing is, Joan, that everyone stands in front of their microwave saying that. Don't they?

Anyway Elizabeth Taylor came from a compliant generation of good girls, who dieted and popped amphetamines to keep their weight down and were belted into corsets so tight that they bruised their lungs.

When Kirstie Alley gained weight she had the American tabloid press dogging her every footstep. As Rebecca in the television series Cheers, Kirstie Alley had the whole world, including Sam the barman, in love with her. Then she did the Look Who's Talking films with John Travolta. Travolta too has his weight issues, but he has never been stalked by the paparazzi on the basis that he had to be revealed to the world as a disgrace to right thinking people everywhere.

Kirstie Alley, on the other hand, was. In bulimic Hollywood she was running out of work. So she came up with the idea of a sit-com based on her new life situation.

After all, Alley told the press, "I'm not the first person in the world to have gotten fat". The television series was approved . . .

this is why you must love America. And it is called, with a simple stroke of devastating genius, Fat Actress.

The title Fat Actress is like Teetotal Alcoholic or Brave Politician. It's just so contradictory that it's a shock. The show has been reported as a success. It is partly improvised, and audiences have liked the first month of it. There's only one tiny problem. Alley has now signed up as the spokesperson for something called the Jenny Craig Diet. She says she wants to lose five stone.