The Consumer Association has named big brand cereals that it says contain too much sugar, salt and fat.
Health concerns have been raised about some cereals
Researchers compared the content of 100 popular cereals with advice from the Food Standards Agency.
It found 85 brands had "a lot" of sugar, 40 had "a lot" of salt and nine had "a lot" of saturated fat.
Many of the worst offenders identified in the study are marketed at children. Nine of these contained at least 40% sugar and 18 contained "a lot" of salt.
The researchers said Nestle Lion Cereal contained so much sugar it was like the chocolate bar of the same name.
Poor performers (per 100g)
Nestle Lion Cereal: 0.75g salt, 13.7g fat, 35.9g sugar
Kellogg's Frosties Turbos: 1.5g salt, 1.5g fat, 40g sugar
Nestle Cookie Crisp: 1.5g salt, 2.9g fat, 41.3g sugar
Nestle Golden Grahams: 2.5g salt, 3g fat, 32g sugar
Kellogg's Frosties Chocolate: 1.63g salt, 4.5g fat, 41g sugar
Kellogg's Hunny B's: 1.25g salt, 2.5g fat, 37g sugar
Nestle Cinnamon Grahams: 1.75g salt, 9.8g fat, 34.2g sugar
Nestle Honey Nut Cheerios 1.75g salt, 3.7g fat, 35.2g sugar
Kellogg's Coco Pops: 1.13g salt, 2.5g fat, 39g sugar
Kellogg's Frosties: 1.5g salt, 0.5g fat, 38g sugar
And they found a serving of either Kellogg's All-Bran, Quaker Oat Krunchies or Nestle Golden Grahams contained four times the amount of salt as a 25g bag of roasted peanuts.
The research also found 13 brands containing hydrogenated or partially hydrogenated oil or fat in the ingredients.
Foods with hydrogenated fats or oils contain trans fats which, like saturated fats, have been shown to raise blood cholesterol levels and are linked to an increased risk of heart disease.
The researchers also found many cereal bars contain high amounts of saturated
fat and all the 11 tested provided less energy and fibre than an equivalent bowl
Nick Stace, director of communications at the association, said: "Breakfast
cereals have a healthy image, yet our research shows that big brand manufacturers are lacing their cereals with such high levels of sugar and salt that it is no wonder that we have a public health crisis on our hands."
Food Standards Agency definitions
A lot of sugar - 10 grams/100 grams of product
A lot salt - 1.25 grams/100 grams of product
A lot of fat - 20 grams/100 grams of product
The watchdog backs the idea of a traffic light labelling system, allowing consumers to see at a glance whether products contain good or bad levels of sugar, salt and fat.
Martin Paterson, deputy director general of the Food and Drink Federation, said the industry had agreed a programme to reduce salt content in breakfast cereals last year.
He said: "The programme showed a 16% reduction in sodium achieved since 1998 in the sector, and an expectation that new products coming to market will continue the trend for products with lower sodium levels."
Benefits of breakfast
A spokesman for Kellogs said an average bowl of the company's cereal with semi-skimmed milk was only around 10% of the recommended daily allowance of calories for children, and contributed only 5% of average daily salt intake.
He said: "Independent research has proven that people who eat breakfast cereals tend to be slimmer than those who don't, because they have lower fat and higher carbohydrate intakes from not snacking as much, not having a high fat cooked breakfast and not eating as much in subsequent meals."
"We believe that all foods have a place in the diet with balance and moderation, and that exercise, together with a balanced diet, is integral to a healthy lifestyle."
Cereal Partners UK, which represents Nestle, issued a statement stressing just how important it was to eat breakfast - particularly for children.
It went on: "We sell a wide range of cereals all of which are clearly labelled as to their nutrient content. All can be enjoyed as part of a healthy diet."
Public health minister Melanie Johnson said most people were aware of the risks associated with high sugar or fat - but were often unaware of the effect of high salt intake.
"What many people consider a health conscious diet is often high in salt.
"Despite claims by the industry that they've taken substantial action, we need to see real steps forward to cut salt levels.
"If we don't see progress then action on food labelling could be the answer."