THEY have seen sales surge as busy workers look for a fast and healthy breakfast to grab on their way to the office.
Starting the day with breakfast biscuits and bars is no better for you than eating an everyday cookie, research suggests.
In fact, a typical serving of a chocolate-covered biscuit like a Hobnob contains less fat and fewer calories than their apparently 'healthy' rivals.
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The breakfast snacks are marketed as wholesome yet convenient by food manufacturers including Belvita, McVitie's and Kellogg's - and it's working, as Belvita has seen an 85 per cent rise in sales this year.
A typical serving of four of their muesli biscuits contains eight grammes of fat and 228 calories, but just two grammes of fibre, trade magazine The Grocer found.
By contrast, eating two Hobnobs means you consume six grammes of fat and just 134 calories, as well as 1.6 grammes of fibre. Two Rich Tea biscuits contain a much lower two grammes of fat and just 76 calories.
Other breakfast bars also fared poorly. McVitie's "Go Ahead Cherry Fruit Bake" may have only three grammes of fat but contains 131 calories, roughly equivalent to two Hobnobs. Meanwhile, a Kellogg's "All-Bran Original Breakfast Biscuit" has eight grammes of fat and 176 calories. It did better on fibre, containing six grammes.
The Grocer magazine said: 'Despite being positioned as a wholesome start to the day, breakfast biscuits contain more saturated fat than biscuit favourites like digestives, Rich Tea and Hobnobs.'
Nutritionist Kate Cook added: 'I can't see any that would make me say, "That's a good breakfast"'.
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The criticism of breakfast bars comes as other research showed that 'healthy' yogurts can have a far higher sugar content than ice cream.
A study produced for The Mail on Sunday by food manufacturer the Natural Ketosis Company found that low-fat mandarin yogurt made by Rowan Glen, which is sold in 125g pots - a typical serving size - has 17.6g of sugar per 100g. This compares with just 12.8g per 100g in Haagen-Dazs vanilla ice cream.
Traditional cereals have also been proven to be less healthy than is often claimed. Consumer group Which? has said many children's cereals are so packed with sugar that they should be put alongside chocolate biscuits on shop shelves.
Breakfast-bar makers said the extra vitamins and minerals in their products made them a better option than Hobnobs.
Sanjeev Hanna, of Kellogg's, said: 'Unlike everyday biscuits, our breakfast biscuits contain six B vitamins, iron and calcium.'
Rahul Gursahani, of Belvita, said: 'Our range contains up to 70 per cent cereals and 40 per cent wholegrain.
'These complex carbohydrates break down more slowly to provide a regular and continuous release when eaten as part of a balanced breakfast.'
And Eamon Donnelly, of Dale Farm Ltd, which makes Rowan Glen products, said: 'This is not a valid comparison because the sugar in this item is naturally occurring in both yogurt and fruit and the added sugar is natural. That is not the case for ice cream.'