The 'diet' foods with more sugar than their non-diet counterparts

Young white man with beard in food store, he is holding two juice bottles.
Yahoo UK compared sugar content between products marketed as 'diet' foods to 'standard'd foods. (Getty Images)

Research conducted by Yahoo UK has revealed which foods that are marketed as ‘diet’ or ‘low-sugar’ foods actually contain more sugar than their regular counterparts.

Over the years, a growing number of brands and supermarkets have released ranges that claim to be healthier by having reduced sugar, with labels describing them as ‘diet’ products or having ‘less sugar’ or ‘low fat’.

Long-time brands like Weight Watchers, which was first established in 1967, are hugely popular, counting hundreds of thousands of Britons as customers.

More recently, the UK government introduced restrictions on the promotion and placement of foods and drinks that are high in fat, salt, or sugar (HFSS), or ‘less healthy’. The laws were put in place in October 2022 and required retailers to move all HFSS products to the back of the store, in an effort to help British consumers to cut down on unhealthy foods.

Some brands reformulated products to comply with the ban - but, according to data from market analysts Reapp, major brands selling non-HFSS-compliant products actually saw sales increase in the year since the law was implemented.

As of October 2023, these brands saw an average sales increase of 27% across chocolates, sweets and chilled desserts. The uptick in sales came despite the laws restricting multi-buy promotions (such as Buy One, Get One Free).

Close up color image depicting a sign with the word 'snacks' in a supermarket aisle. Focus on the sign with the snacks on the shelves defocused beyond. Room for copy space.
Retailers and brands reformulated some products to comply with new HFSS regulations - but some products slipped through the net. (Getty Images)

However, Action on Sugar, a charity formed by specialists who are concerned about the impact of sugar on health, said in a report on high sugar sales that while supermarkets were keen to put forward their reformulated products as having lower sugar content, it only applied to existing products.

“In some cases, what supermarkets describe as reformulation could in face mean new product development - or ‘formulation’, the development of ‘low sugar’ products, in addition to existing higher sugar recipes, for example ‘low sugar’ muesli sold alongside a very similar product which is higher in sugar,” the report said.

“Retailers emphasised their aspirations to increase the ratio of healthy products sold, however by continuing to sell low/no added sugar variants, alongside higher sugar ‘standard’ products, they lay the emphasis on shoppers to make the healthier choice.”

But it doesn’t stop there, as analysis by Yahoo UK found that even products marketed as ‘low sugar’, ‘low fat’ or ‘diet’ may contain higher sugar content than ‘standard’ versions - this applied to a range of products, from biscuits to custards, and even coleslaws.

For example, our analysis found that Weight Watchers Caramel Wafers (milk-chocolate coated caramel wafer bars claiming to have just 73 calories per wafer) contain 43g of sugar per 100g.

Each wafer is 16g, which means customers consume 6.9g of sugar with every wafer. In contrast, Cadbury Fingers Milk Chocolate Biscuits contain 35g per 100g, equivalent to 7.4g per 21g (approximately four biscuits).

On the other end of the scale, McVities Digestives The Original seem to have the lowest sugar content - coming in at 15.1g of sugar per 100g, equivalent to 2.2g per biscuit. It’s worth noting that McVities Chocolate Digestives still have lower sugar content compared to the Weight Watchers wafers, with 28.5g of sugar per 100g (4.8g per biscuit).

We also compared snack bars and found that a product in Kellogg’s Special K range, which is often touted as diet foods, contains more sugar than brands like Go Ahead and Nature Valley.

A woman standing in an isle in her local supermarket and reading the product label of an item while out grocery shopping.
Customers may be surprised to find out that some products labelled as 'diet', 'low sugar' or 'low fat' actually have higher sugar content than their 'standard' counterparts. (Getty Images)

Kellogg’s Special K Juicy Red Berries bars contain 27g of sugar per 100g (5.8g per 21.5g bar). The product is described as containing “wholegrain cereals mixed with cranberry fruit pieces infused with a strawberry flavour”, and claim to be a source of vitamin B3, B6 and B9.

In comparison, Go Ahead’s Golden Baked Oaty Bars with Apple Flavoured Filling contain 22.3g per 100g (7.8g per 35g bar) and Nature Valley Protein Peanut and Chocolate Cereal Bars have 15.4g of sugar per 100g (6.2g per 40g bar).

Even coleslaw and salad dressings might contain more sugar than you think. M&S’s own-brand Reduced Fat Coleslaw, which has a “reduced fat mayonnaise”, has 6.2g of sugar per 100g (18.6g per 300g pot) - two grams more sugar than Tesco’s Finest Coleslaw containing regular mayonnaise (4.2g per 100g, 12.6g per 300g pot).

In the world of salad dressings, Mary Berry’s Light Salad Dressing - which is described as having “50% less fat” - contains a surprising 14g of sugar per 100ml (3g per 20ml serving).

This is significantly high compared to Sainsbury’s Caesar Dressing, which has 3.8g of sugar per 100ml (0.6g per 15ml serving). Other salad dressings which lower sugar content than Mary Berry’s brand include Pizza Express Caesar Salad Dressing (6.4g per 100ml) and Hellmann’s Fat-Free Vinaigrette (11g per 100ml).

To find out more about your favourite foods and how much sugar they contain, click through our interactive chart below:

Commenting on Yahoo's findings, nutritionist Sonia Pombo from Action on Sugar says: "Shoppers shouldn't have to look twice when switching from standard to 'healthier' alternatives, but unfortunately some products can be deceptive.

"Foods claiming to be low fat or sugar often do not differ much from others, and in some cases can result in higher levels of other less healthful nutrients. These products are targeting the health-conscious shopper, who should expect these products to be lower in fat, salt or sugar, when in fact they aren’t.

"Instead of misleading customers, companies should be doing all they can to improve the nutritional quality of all the products they sell, to protect out health from avoidable illnesses and early deaths."

Sugar comparisons per 100g at a glance

  • Weight Watchers Caramel Wafers: 43g per 100g

  • McVities Chocolate Digestives: 28.5g per 100g

  • Kellogg’s Special K Juicy Red Berries bars: 27g per 100g

  • Nature Valley Protein Peanut and Chocolate Cereal Bars: 15.4g per 100g

  • M&S’s own-brand Reduced Fat Coleslaw: 6.2g per 100g

  • Tesco’s Finest Coleslaw: 4.2g per 100g

  • Mary Berry’s Light Salad Dressing: 14g of sugar per 100ml

  • Sainsbury’s Caesar Dressing: 3.8g of sugar per 100ml

Yahoo UK has contacted Weight Watchers, Kellogg's, M&S and Mary Berry for comment.

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