Supersize vs Superskinny
Channel 4, 8pm
No early copies of the first episode were available in time for my deadline last week, but this week I wasn’t so lucky. A very kind lady at Endemol had it biked halfway across the country at vast expense toget to me in time, but . . . frankly . . . it’s entirely horrible. It features one woman shouting at other women about their big bottoms; another woman has a colonic massage and boasts of having had the biggest poo of her life afterwards; and a lady with eating phobias who is dangerously underweight is encouraged to eat the diet of a young man who is clinically obese – and vice versa. Who on earth had the bright idea of encouraging someone to eat more by confronting them with mountains of repellent food? But say what you like about Endemol, they’ve got a cracking PR department.

Mistresses
BBC One, 9pm
All four mistresses of the title are in extremis. One is having an affair with the son of her former lover and doesn’t know whether or not to tell him he’s a chip off the old block. Another is pregnant by her lover. The third can’t decide if she should have sex in the afternoons with that nice Patrick Baladi from the school run – a relationship that is further complicated by the sudden arrival of her deceased husband’s ex-lover. And the fourth isn’t sure whether she likes men or women – or both. So am I, to be honest. I don’t know where this improbable nonsense is heading, why it is going there or if there is any point going along with it.

Horizon
BBC Two, 9pm
A brilliant and funny young particle physicist called Dr Brian Cox presents this fabulous Horizon. It would seem that gravity holds the key to discovering a grand theory of everything. Newton’s laws of gravity were good enough to get a man to the Moon, but they are ultimately “just an approximation” and don’t begin to answer the big questions such as “how” or “why”. Einstein’s theory of gravity – based on space and time woven together, bending and curving – works with the big stuff but falls apart at the level of sub-atomic particles. Now it seems that particles of gravity may spend most of their time hanging out in extra, unseen dimensions. “You dig deeper,” says Dr Cox, “and it’s more and more complicated. But it’s beautiful.” Who needs drugs when you can get stoned on Horizon?

Medicine Men Go Wild
Channel 4, 9pm
The intrepid young doctors travel to Malaysia, Nepal and India to learn about alternative methods of pain control. The programme is filled with images of agony. Metal skewers are thrustthrough cheeks; a woman has a rotten tooth burned out with a poker, and people are suspended in the air by hooks dug into their backs. Seeing all this, the doctors come to believe the pain does not disappear, but people are somehow able to control their reaction to pain and not to mind it. The problem with this series is not the subject matter, but that its treatment is anecdotal, inconclusive and overly telly-friendly. It needs to be less Michael Palin and more Horizon.

Editor's choice

• Are Glasvegas the new Oasis?
• 50 most memorable moments
• Vote for musical perfection