Ellie Levenson: Now it's Prezza's turn to show his feminine side

At the now-closed Backyard Comedy Club in Bethnal Green, there used to be a competition during the interval where audience members were given two seemingly unconnected subjects and asked to come up with a joke linking the two. George Bush and a McDonald's happy meal, for example, to which an answer might be that they are both full of crap and trying to take over the world.

Not once though did they ever think of asking the audience to set their minds to John Prescott and Princess Diana, though if they had, a few similarities could have been drawn – a string of inappropriate affairs, a penchant for flashy cars and the love of the good people of Hull. It's unlikely though, until this weekend, that anyone would have thought of bulimia as the link between the two public figures.

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For we may have thought we knew it all about Prezza – his favourite Chinese restaurant in Hull, the Tracey Temple affair, the throwing punches in Rhyl during the 2001 election campaign, but, and here's another Princess Diana link, like the disgraced butler Paul Burrell, he's held something back to ensure some book sales. In his new autobiography, Prezza: Pulling No Punches, he admits to suffering from the eating disorder that can see sufferers gorge on as many as 20,000 calories at a time and then vomit to purge themselves immediately afterwards.

"Once I got into the shadow cabinet, trying to produce pamphlets and documents, stuck in an office, hour after hour, the only break I ever took was to eat. That's all I did. Work, and then quickly eat something. It became my main pleasure, having access to my comfort food. So what I did was stuff my face with anything around, any old rubbish: burgers, chocolate, crisps, fish and chips, loads of it, till I felt sick – but at least I'd had the pleasure of stuffing my face and feeling really full. Then there would be a weird kind of pleasure in vomiting and feeling relived."

It's somewhat surprising. We knew he was two jags, and after the Rhyl incident he became known jokily as "two jabs", but it was Charles Clarke who was the Labour MP known as "two pizzas" after being spotted having a very large meal in the Victoria Street branch of Pizza Express near Westminster. In fact it was during these two pizzas that he was caught slagging off Prescott and calling him "useless", ironic really as we now know it could so easily have been Prescott having the two pizzas and Clarke being called useless.

Sadly, it's always tempting to make jokes about eating disorders. I say sadly because I do acknowledge that they are terrible diseases that ruin the lives of sufferers and their families. But when I dabbled in stand-up comedy I did have my own bulimia joke. I'd talk about being fat and then say that I may be fat but actually I have an eating disorder, that I'm half bulimic. The joke of course was that the half I had was the bingeing and the half I didn't have was the throwing up.

Prescott's admission does lay him open to bulimia jokes of his own, not least because his bulimia didn't make him thinner – he is still over 15 stone. Being unkind, one could draw parallels between this and his reign at the Office of the Deputy Prime Minister – a lot of effort, not really many visible results.

Joking aside, though, and I do think it's fair to joke about public figures when they make revelations in autobiographies that have been written in order to make money, it is brave of Prescott to come out about his bulimia, just as it was for him to talk about his diabetes in the 1990s, using his personal experience to promote government awareness schemes around the disease.

Prezza claims that, as with his diabetes, his motivation in coming out about his disorder now is to help other people who may also have it. I don't think Prescott is an idiot for having bulimia – mental illness can strike anyone. But I do think he's deluded if he thinks his admission is going to help other sufferers. First off, they may be slightly peeved by the way he talks about having a "girl's illness" – "I turned up [at the consultant's office] and found his waiting room full of young women. I was the only man there. I felt like a right twerp."

Second, it's not like someone saying, "Oh it's OK, Britney Spears has it too." If today's young women have heard of Prescott, and my guess is that most haven't, I shouldn't think that they will feel that by having the same illness some of his glamour and panache will rub off on them. If it did, for a young woman with self-image problems, that really could be a disaster.

ellie@levenson.net