Watching your weight? Then you'd better not be watching Masterchef.  According to the latest research, TV cookery series like Masterchef, Great British Bake Off and Come Dine With Me make us fat - and it's put down to the fact that six out of ten people admit they snack during or after their favourite foodie shows. It's the obvious equation: Watching food being prepared on TV makes us hungry, and we end up piling on the pounds by snacking on treats like chocolate, crisps and biscuits.

Nutritionists looking into the reasons people consume unnecessary calories before or after big meals found that cookery shows were one of the worst offenders. With hunger as the main reason people snack, boredom comes a close second, blamed by 63 per cent of those polled as the reason they'll reach for the snack bowl. Other reasons include the temptation of having lots of food in the house, enjoyment of eating whilst watching TV, a partner's influence or simply walking past the fridge.

But TV cooking shows were voted the worst of the seven deadly sins for causing us to eat when we shouldn't. The five main channels now show 40 cookery shows a week - and it's not often light food they are cooking on air. As well as making an unlikely heartthrob of its host Paul Hollywood, BBC2’s The Great British Bake Off is said to have sparked a boom in cake and pastry making too. Come Dine With Me is aired 15 times a week on Channel 4 and remains one of its favourite shows.

BBC1 is currently screening five different cookery shows and BBC 2 has four. And with all those show, there is a lot of snacking going on. A large majority of us (63 per cent) admit snacking during or after watching our favourite cooking shows. Chocolate is our favourite snacking food - chosen by 37 per cent of respondent - followed by crisps, biscuits, pizza and toast.

The poll found that more than a third of us have three to five biscuits when we open a packet - 21 per cent limit themselves to one or two, 16 per cent have between five and seven and eight per cent of us will polish off the whole packet. Finishing off the list of deadly snacking sins created by the nutritionist is the hard-to-resist bag of nuts with a pint. A pub visit means a snack of crisps of nuts for 58 per cent of us. Coming back from the pub is another trigger for superfluous calorie consumption,with  69 per cent of us get an attack of the munchies before we go to bed after a night out.

FORZA managing director Lee Smith, who carried out the survey, said: 'Who hasn't got the munchies when they have been watching Masterchef or Come Dine With Me? 'Even if the dishes they are preparing are rubbish, just the sight of all that grub makes us peckish. 'There are so many shows on TV devoted to making us fat - I'm surprised they don't have a calorie counter on The Great British Bake Off because all they seem to be doing is inviting us to gorge on cakes. 'And don't get me started on the Hairy Bikers - they look like they have gobbled up their bikes as a starter and are waiting for the main course. 'The key to successful dieting is to avoid snacking unnecessarily in between meals on crisps, biscuits and chocolates.'