Last Night's TV: Just who do they thing they're kidding?

My Fake Baby, Channel 4; Half Ton Mom, Channel 4

Terry and Sue had never quite got round to having a baby. "We've not pursued it, so to speak," explained Sue. "I can't do the noise and I'm just so fussy, really. If I could pick a child off the shelf that would be wonderful, because I'd be able to say, 'Yeah... I want one that's quiet, one that's well behaved, I want one that keeps clean...' but obviously the reality isn't like that." Well spotted, Sue, and perhaps you were wise to opt instead for a reborn, an uncannily realistic model of a baby that lacks the inconvenient orifices. You fill their formula bottles with fabric conditioner ("It doesn't go mouldy") and, if you're so minded, wheel them around the local park, where half the people you encounter will edge away from you nervously and the other half will coo helplessly at your baby's sweet little fingernails. In My Fake Baby, Sue turned out to be expecting, just about to take delivery of an "Open-Eyed Smiler" from a US supplier of reborns. Naturally, the imminent arrival needed clothes to wear, so Sue hauled Terry off to Harrods, where she blew nearly 300 on Roberto Cavalli babywear, happy in the knowledge that they would never be puked upon:"It's money well spent rather than wasting money," she explained to a heroically poker-faced sales assistant.

Victoria Silver's film had begun with the unsettling image of Jaime Eaton putting one of her babies into the oven to dry, head and limbs carefully arranged on a baking tray like a cannibal's special-selection platter. Jaime makes reborns (you can see the decidedly creepy verisimilitude she achieves by checking out the Babybuntins Nursery website) and she was in the process of creating one for Christine, a woman who you initially assumed to be in the grip of a recent bereavement: "I would just like him back again," she said tearfully, showing off photographs of a little boy up a tree. Visiting another collector, Christine stroked a tiny vinyl hand pensively: "Harry had long fingers," she said. Who are we to judge, you thought, if this poor woman seeks consolation this way?

Then it was revealed that Harry was actually her grandson and he wasn't dead at all, just off in New Zealand with his mum, and you started getting dubious all over again. Christine was moved to tears when she eventually took delivery of Harry 2.0, customised down to the last forehead vein and stork-mark, but he didn't go down very well with Christine's husband, Arn: "It makes me think of something on a mortuary slab," he said when Christine unveiled the newest member of the family. As he bolted for the door, you could hear an awful off-screen wail, as though a death had been announced, but Christine had pulled herself together again when the time came to introduce Harry 2.0 to Harry 1.0 on a webcam link to New Zealand: "What do you think of my baby," she said, adopting the same besotted croon that all the collectors employed when talking of their reborns. Harry 1.0 cut straight to the heart of thematter: "It's a doll, you numbnut." Sue, meanwhile, bonding with Sophie in a Washington hotel room, had discovered that she was cracked beneath the hairline and was furiously planning to send her back for repairs. That's another problem with real children no returns policy.

Earlier in the evening, perfectly scheduled for the peak season of post- excess bloat and self-loathing, Channel Four had offered us Half Ton Mom, in which Renee Williamson 64 stone of self-denial had submitted herself for gastric bypass surgery. Renee began by forcefully striking out the misconceptions that she most disliked about the super-obese. She didn't smell, she said, and we shouldn't assume that she ate a lot. I wasn't convinced by either of these assertions, given that outlying parts of Renee's imperial bulk were actually suppurating and that we later learned that eight burgers counted as a light snack.

The film itself wanted to have its cake and eat it, a zero-calorie enterprise that nonetheless left you feeling a little guilty about consuming it. On the one hand we were enjoined to admire Renee's courage and inner- beauty; on the other hand we were never for a second deprived of the carnival satisfaction of inspecting the absolutely astounding mess she'd made of herself. She was so huge that the doctors operating on her had to bolt two surgical tables together to accommodate her body, and even then they feared there would be overflow. And, sadly, Renee had left it too late to get to grips with her own compulsive psychology. Though the operation was a success, her heart gave out while she was convalescing. This was a bit of a shock, given that such programmes usually like to end on a note of triumph and that we knew Renee's young daughters would be devastated by their mother's death. She ate and the weight settled on them.

t.sutcliffe@independent.co.uk