It's hard to know what's more insidious - documentaries that exploit people just about weird enough to be interesting , or those shows' attempts to position themselves as anything more constructive than a chance to point and laugh.

Despite the tact-free title, Freaky Eaters: Addicted to Chips (BBC3, 17 March) persevered with the pretence that it wanted to help its subject escape the pathologically narrow diet that was blighting his life.

This week's cautionary tale saw Dave braced for university, burdened with the "dark secret" of his lifelong obsession with stick-shaped spuds.

The "month-long dietary makeover" is essentially a foodie intervention, tantamount to the common US practice of bundling your kids into the back of a van and beating them with sticks until they give up the skag . Indeed, the motivational technique here - marching Dave to a deserted cinema and beaming 10-foot high messages from family members saying he's fat and will die soon - presumably falls into the 'tough love' category.

Guilt-trips aside, dough-faced Dave was clearly not in a good way.

"Without chips I wouldn't eat," he confided/bragged, amid tutting from a crack team of psychologists and nutritionists assembled to prove that a chips-only diet might not be particularly healthy. "I'm afraid of green foods, the smell of green foods. It smells like the garden," he reasoned. "And I don't want to go into the garden and eat the grass."

A gratifying early scene saw Dave presented with the 300kg of chips he would eat in a year. He looked peckish rather than mortified.

But the coup de grease was a lecture from vitamin expert Dr Pixie McKenna on his chronic B12 deficiency. For someone "ashamed I'm not grown up enough" to take his girlfriend to a restaurant, a televised dressing-down from someone called Dr Pixie was probably not what Dave needed.

Yet the show was not without pathos. "I don't want to be an outcast straight away," Dave said about university, perhaps with an eye on becoming a hermit in his second year.

No danger. Look out for a reprise featuring Dave addicted to chicken-flavour Super Noodles three years from now.