Alice Jones: If a diet 'doctor' can shift your flab, do you care if they're not an actual medic?

We're so proud of little Josh. Five A*s in his GCSE mocks and this week he came top of the class for carb deprivation!" An unlikely scenario? Not if Pierre Dukan has his way. The man best known for coming up with the high-protein, low everything else diet which whittled the Middleton females into walking mannequins pre-wedding has suggested that French schoolchildren should have the option of taking weightwatching as well as reading, writing and arithmetic.

Pupils would pass the "ideal weight" exam and gain points towards their final Baccalauréat score simply by staying within 18-25 on the Body Mass Index: who says education is all about making progress?

Even taking into account dinner ladies' penchant for cottage cheese (one of the few foods you're allowed on the Dukan plan), one doesn't need a phoney PhD in holistic nutrition to see the problems with his idea.

Students who are already vulnerable to eating disorders would face added, curriculum-legitimised, pressure. BMI scores would become another stick for bullies to beat the fatties with in the playground. Far better to help teenagers to keep healthy through education, nutritious meals and regular PE lessons. Radical, but it might just work.

Dukan now faces being struck off by the French College of Physicians who have charged him with breaching guidelines by failing to consider the impact of his comments. While the letters after his name might be in jeopardy, his place on the bestseller lists is surely safe. Most of his acolytes will simply be surprised that he was a qualified doctor in the first place and go back to nibbling on a prawn.

It is not medical credentials that attract people to diet "gurus" – if it was, we wouldn't call them "gurus", with all the magical mumbo-jumbo that implies – it is results. Even if the diet in question features an alarming "attack" (read starvation) phase and bans vegetables, people will sign up if they think it will make them thin. Taking the words of multi-millionaire nutrition writers as bona fide medical advice is as dumb as being shocked when television's excrement-sifter extraordinaire "Dr" Gillian McKeith was exposed as not being a real medic, or believing DJ Dr Fox is a practising GP.

Ask a real doctor how to lose weight and they will give you the same old, celebrity-free, non-bestselling advice we all learned at school – eat less and exercise more. Dukan is also charged by the College of Physicians with focusing more on commerce than on medicine. He'll find that one harder to counter but with seven million copies sold and counting, I doubt very much that he'll care.

* Mad Men returned to television this week and Sky had the rather neat, if financially suicidal, idea of resurrecting vintage commercials in the breaks, to better immerse viewers in the world of the show set in a 1960s advertising agency.

There was the dashing Milk Tray man, there were Nanette Newman's hands doing dishes and there was Tony Hancock preparing to go to work on an egg.

Like all the best campaigns, the stunt got people talking and raised the question – were adverts better in the old days? On this evidence, they certainly inspire more affection and less irritation than the current crop.

Naturally we're inclined to look upon adverts more kindly when we feel we're no longer being flogged the product but they were just a bit cooler in the past. Mad Men, of course, is entirely predicated on the notion that a vintage sheen hides a multitude of sins. No one would dream of sitting through five seasons of a show about modern-day obnoxious ad execs: remember The Persuasionists? Exactly.

Besides, I can offer empirical evidence. Last year, my flatmate and I held a house party where you had to come dressed as your favourite advert. Why? Because we're that cool. In any case, among the guests we had eight Milk Tray men, three Milky Bar kids and just one lonely Go Compare! opera singer. Enough said.

Twitter: @alicevjones