Some branded muesli no healthier than KitKat cereal, Which? finds

• A Which? investigation revealed that expensive, branded mueslis are often less healthy than budget versions, with some premium products containing high levels of saturated fat and calories that result in lower nutritional scores than a Nestlé KitKat cereal
• Supermarket "essentials" and "savers" ranges from Asda, Morrisons, and Sainsbury’s were among the healthiest tested, costing as little as 10p per bowl—eleven times cheaper than the lowest-scoring premium brand.
• Products labeled "no added sugar" frequently contain up to 20g of sugar per 100g from dried fruit, while "wellness" ingredients like coconut chips can significantly drive up saturated fat and calorie content.
  

A new Which? investigation has found that some mueslis may not be any healthier than Nestlé KitKat cereal and can contain up to 20g of sugar per 100g, while the healthiest can cost a tenth of the price of some premium-branded rivals.

The consumer champion analysed 86 muesli products on sale in UK supermarkets and found that while it is generally a healthy choice, some of the most expensive, premium-branded products are among the least healthy on the shelf. 

The Which? research found that while muesli, as a category, is generally a strong way to start the day, some varieties may be no healthier than a bowl of cereal based on a chocolate bar.

Which? assessed mueslis using the 2004 Nutrient Profiling Model (NPM) – the same system used to decide whether foods are high in fat, salt or sugar (HFSS) and therefore restricted from prime advertising slots and in-store promotions. Under the model, products are scored out of 100 on both positive nutrients, such as fibre and protein, and negatives, including sugar, saturated fat and calories.

The lowest scoring item in Which?'s study was Raw Gorilla Keto Mighty Muesli, which scored 46. This is because while it is a specialist keto product and therefore low in sugar (1.5g per 100g), it also is higher in calories than standard muesli and is very high in saturated fat (12.2g per 100g) due to coconut chips. 

Next on Which?’s least healthy muesli list was another branded product, Eat Natural Gluten Free Buckwheat Toasted Muesli (scored 50), with 15.3g of sugar per 100g and also high in saturated fat from coconut (7.4g per 100g) – despite high protein and fibre from various seeds.

For comparison, Which? found that Nestlé’s KitKat cereal, which, like the chocolate bar, is made of chocolate and wafers, scored 56 out 100. This product is almost a quarter sugar (24.9g per 100g) and was slammed in 2023 by health campaigners, who claimed it was being irresponsibly marketed as a “nutritious choice”. 

Also on Which?’s list of the least healthy mueslis, with a score of 60, Mornflake Classic Fruit and Nut Muesli got maximum penalties for sugar (18.5g per 100g) due to its high dried fruit content.

The Which? investigation also exposes how shoppers are tripped up by packaging claims. Labels such as “no added sugar” are technically accurate but frequently misleading. Some of these products still contain high levels of sugar from dried fruit, pushing totals close to 20g per 100g.

Completing the least healthy list, and fourth from the bottom was Waitrose Essential No Added Sugar Fruit and Nut Muesli, scoring 62 out of 100. Despite the ‘no added sugar’ label, it contains 19.5g of sugar from dried fruit, plus saturated fat from coconut. Reasonable fibre and protein levels are not enough to cancel these out.

The results upend a familiar assumption: that premium equals healthy. Which? found that some value mueslis, built around simple wholegrains with modest amounts of fruit and nuts, scored top marks. 

The healthiest mueslis on test - six out of 86 muesli products - achieved a score of 80 out of 100. Three of them are from supermarket value ranges including Asda, Morrisons and Sainsburys. As well as being the healthiest, the own-brand products were also the cheapest, costing less than 10p a bowl (20p per 100g) - eleven times cheaper than one of the priciest products Which? looked at, the Raw Gorilla Muesli (£2.20 per 100g).

Shoppers still face widespread confusion about food labels. In a separate Which? survey, a third of consumers said they struggle to interpret them, while traffic-light nutrition labelling remains voluntary and inconsistently applied. Add oversized bowls pictured on packs – a phenomenon called “portion distortion” – and even health-conscious shoppers can find themselves overserving calorie-dense cereals.

Despite the pitfalls, Which? found that overall most mueslis sit comfortably in the healthy middle ground. Their core ingredients deliver fibre, which helps maintain steady energy levels and avoid the sugar spikes associated with more processed cereals or pastries. Eaten with milk or fortified plant-based milk alternatives, they also contribute meaningfully to daily calcium intake.

Shefalee Loth, Which? Nutritionist, said:

“Muesli remains a solid option for a balanced breakfast, thanks to its combination of convenience and fibre. However, not all blends are created equal.

“Expensive price tags, premium branding, and wellness buzzwords don't guarantee nutritional value. In fact, the healthiest options are often the simplest and the cheapest, so it’s worth reading the small print if you are worried about sugar or saturated fat.”

Notes to editors:

• Which? used the 2004 NPM (nutrient profiling model) to establish the healthiness of the mueslis. This is an established system primarily used by retailers and manufacturers as the basis for TV and in-store advertising and promotional restrictions for HFSS (high in fat, salt or sugar) products. 
• NPM scores are calculated by taking into account both positive/ beneficial ingredients, such as fibre and protein, and less beneficial ingredients, including sugar and saturated fat. Using an official NPM tool yields a final score indicating either ‘pass’ or ‘fail’ for HFSS purposes. 
• An updated NPM, backed by the government, has been developed and will be rolled out in due course, guiding even healthier dietary choices. 
• Crucially, there’s the ‘protein lock-out’, an inbuilt safeguard that cancels out a muesli’s protein content if manufacturers try to use it to offset a highly sugary formulation. 
• With the help of Professor Mike Rayner, who was pivotal to the original NPM’s development, Which? used an evidence-based equation to transform the NPM scores into a more consumer-friendly format. Which? awarded scores from 0 (least healthy) to 100 (most healthy), with everything in between.
• Data was collected in May 2025, product formulations were last checked 25th February 2026

Nestle condemned for 'irresponsible' KitKat cereal campaign

Advice for consumers

First, check the ingredients list. If sugar or dried fruit appears right at the top, expect a sweet cereal no matter what the front of the pack says. Second, beware coconut. Third, aim for at least six grams of fibre per 100g. And finally, measure your portion — your bowl is probably bigger than you think.

Rights of reply:

Which? sought responses from all four manufacturers which scored below the 62 threshold, however Eat Natural and Waitrose did not provide a comment for inclusion.

A Mornflake spokesperson said: “Mornflake produces a wide range of breakfast cereals to offer choice for different consumers. More than 90% of our range is HFSS compliant; the product reviewed is one of only a small number classified as HFSS, but it contains no added sugar and is high in fibre.

“We provide clear ingredient and nutritional information, including front-of-pack labelling, so shoppers can make informed choices. We have not received consumer complaints regarding the nutritional content of this product.

“Reformulation to help shift taste preferences takes time, but we are actively reducing HFSS across our range and working with UK Government departments to support long-term improvements in diet and health.”

A spokesperson from RawGorilla said: "Comparing a specialist KETO product to sugary ultra-processed cereals highlights the limits of the NPM method, a ‘one-size-fits-all’ mathematical model. RAWGORILLA KETO Mighty Muesli is a 100% organic whole-food product, made with activated seeds and nuts, with zero added sugar. It is designed for a KETO diet. While the system penalises the natural energy density and the fat content of our seeds and nuts, it ignores the vital difference between unprocessed whole foods and ultra-processed products. 

"Unlike refined cereals, which cause a quick sugar spike, our ingredients provide slow-release energy. We urge shoppers to look past the maths and read the ingredients list; real health is about the quality of the food, not just a calorie count."

About Which?

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