The Truth About Food (BBC2); Tourette de France (C4): As the burlesque performers sing in the musical Gypsy, "You gotta have a gimmick".

The Truth About Food has several in a bid to keep the interest of viewers.

One is presenter Fiona Bruce, plucked from behind a BBC News desk and, while not quite getting to kick her legs like Angela Rippon did on that famous Morecambe and Wise show, does get to talk dirty.

Hear Fiona say "erection". See Fiona gasp as a pill-cam passes through someone's body sending back pictures of their insides. Watch Fiona have her cholesterol level checked.

Those gimmicks are only the tip of the iceberg lettuce introduced to disguise that this is yet another programme telling us what's good for us, a sort of nanny state production.

Over the series, we're promised 40 trials and demonstrations involving 500 volunteers and some well-known personalities. One experiment put nine people with high blood pressure and cholesterol levels on a raw fruit and veg diet.

The gimmick was they were made not only to eat like apes but to live like them in tents in an enclosure in a zoo, something that undervalued a serious, worthwhile experiment, not to mention producing enough farting to power a jumbo jet.

Two truckers with constipation were helped. For one, it took 42.5 hours before his breakfast re-emerged. The solution was to add fruit and bran to their diet - "and stand well back," suggested Fiona, who couldn't resist adding, "There's plenty of movement in the zoo".

David and James wanted their sex lives (not with each other) perking up. After eating four raw cloves of garlic every day for three months, I don't think anyone would want to get near them, let alone engage in intimacy.

"Is it working?," asked Fiona coyly, before uttering the e-word.

Scientist Gemma - known as Miss Poo to her friends - examined daily deliveries of faeces to see which diet best destroyed bad bacteria.

Fiona's cholesterol test found she was supernormal, possessing a rogue gene that makes it unlikely she'll suffer from heart disease. Good news for the ape people too as the group's cholesterol levels dropped an amazing 23 per cent.

Apart from the jokey title, the gimmick in Tourette de France was to put unpredictable actor Keith Allen, the Sheriff of Nottingham in the BBC's Robin Hood, on a double decker bus carrying Tourette's sufferers on a trip to France to visit the hospital where the condition was "discovered".

Tourette's causes sudden involuntary body movements and verbal outbursts so onlookers can seem perplexed and upset by their behaviour. The trip was led by John Davidson, billed as Britain's best-known Tourette's sufferer thanks to a QED documentary 20 years ago that must have shocked a nation unused to reality TV.

Here, the Allen gimmick worked because he was a sympathetic listener and his travelling companions a quirky, but likeable bunch. They wanted to show they were like other people - and succeeded admirably, without being locked up in a zoo or made to swallow a mini-camera.