Last Night's TV - Fast Food Baby, BBC3; Britain's Next Big Thing, BBC2

I got no control over what he eats," said one of the parents in Fast Food Baby. The man voicing this hapless admission of surrender was about six-foot tall and weighed – at a rough guess – around 16 stone. The infant who had overmastered him was about two-foot high and can't have weighed more than three stone, though he was already working hard to catch up with his father, grazing almost continuously on takeaways, sweets and up to six cans of cola a day. And, yes, having gone mano-a-mano with a three-year-old myself in the past, I know that the weigh-in can often be deceptive about respective strength. But even so. From the very beginning of BBC3's film, it was clear that parental spinelessness is the very worst thing you can add to a child's diet.

Cuba's mum and dad grasped the basic theory of healthy nutrition, but were too daffily fond to apply it. "It's hard to say no to him," said Cuba's mum, who had sidestepped the effort of trying by filling a floor level cupboard with edible trash, so that Cuba could top up his calorific intake whenever he fancied. Kara and Gareth, by contrast, really did appear to be trying hard to get a few vitamins into their son, but had been left fatally susceptible to his crying by a near-fatal bout of meningitis. He now understood that all he had to do to get fish and chips and his favourite television show was to grizzle for a while. And Taylor, a single mum living in Runcorn, was actually intervening to prevent her son's diet improving even by accident. "I like pears!" he said, fingers grasping curiously as he was wheeled past the fruit in the local supermarket. "Ugh!" replied his mother. "You've never tasted a pear."

Programmes like this present us with a have-your-cake-and-eat-it deal when it comes to judgemental superiority. We know that we're not supposed to look down on those depicted, and that they will eventually be coaxed into the light by nutritional missionaries. But the set-up makes any other perspective pretty much impossible. As you watched Taylor's son Harley guzzling down cola and listened to her explain that she hadn't taken him for a dental check-up because she's scared of dentists, it briefly occurred to you that his best prospect of healthy diet would be a more serious recurrence of the heart attack his mother had already had. She never wanted to go through anything like that again, she assured us earnestly, in one of the brief gaps when she didn't have a kebab, or an alcopop or a cigarette in her mouth.

Never despair though. Not only did Kara and Gareth learn some techniques for getting fresh food into their son, Cuba's mum and dad also took their first hesitant steps towards home cooking. Taylor even claimed on camera to have seen the light, cooking up a healthier home-made pizza after attending a single mum's cookery class. In her case, I suspect that the dietary virtue will stick for about as long as a microwave pizza would adhere to the kitchen wall, before sliding loose in a puddle of hydrogenated fats, but it's possible that the sight of her dim-witted delinquency will have stirred a determination to do better in at least some of the programme's viewers.

"It's now time for the nitty-gritty of business," said Theo Paphitis in Britain's Next Big Thing. "The fun starts here." The programme has now got beyond the selection process, in which top British retailers selected the products they wanted to put on their shelves, to the bit where the details of costing and delivery have to be worked out. And not everyone agreed with Theo's characterisation of the narrative curve. "This is where the hard bit starts actually," said Andy Atkinson, a category manager for Boots, "this is the hard yards."

They were certainly eye-opening for anyone who was assuming that catching the eye of a big store was a certain route to profit. Charlotte Sale, whose rather beautiful splash-shaped glass bowls had been snapped up by Liberty, revealed that she was supplying the big ones on a sale-or-return basis, meaning that she had to front up £1,000 just to supply the order, with no guarantee that the items would sell. And Catherine Gray discovered that if she licensed her ceramic vase design to Habitat she would end up with just 30 pence per sale. If they sold 3,000, she would get just £900 out of the deal, while simultaneously undercutting the market for her own more expensive bespoke versions. And nobody mentioned the fact that both retailers are dedicated to a fashion cycle, ruthlessly moving on from one design once the profit had been squeezed out of it. The hardest lesson was for Elaine Weston, whose home-made range of teenage cosmetics suffered death by focus group, after a panel of teenagers had unerringly identified its commercial defects.

Theo tried to make us feel sympathy for the big retailers by demonstrating how slender the profit margins are once all the overheads have been paid off, but he couldn't really conceal the fact that the only area in which the creators and the craftsmen were getting the biggest slice of the pie was when it came to taking on the risk. If you found yourself hankering after one of Charlotte's bowls, now that Liberty's buyers have endorsed their good taste, you might want to buy directly from her so that she gets a bigger share of the pie. She does have a website.