That bowl of muesli you conscientiously ate for breakfast may not be as healthy as you thought, a new survey shows.

In a Consumer magazine test of 75 muesli brands, one was found to have almost the same amount of fat and salt as corn chips, and more than four times as much sugar.

Several brands contained high sugar levels of more than 15 grams per 100g of cereal. Many contained added sugars, sometimes disguised as honey, golden syrup, maple syrup or glucose, and some used dried fruit that had been sweetened with sugar.

Of the 75 supermarkets and health food store brands tested, only 12 had low levels of fat, sugar and salt.

Muesli sales were worth $34.8 million last year and growing, the magazine said.

However, Consumer NZ chief executive Sue Chetwin said the organisation was unable to recommend muesli as a healthy breakfast option. It called for simple "traffic light" nutritional displays on packets.

"Consumers might think it's healthy, but they don't realise about all the added things like sugars, nuts, oils and seeds."

Donnell Alexander, a member of Dietitians NZ, said a good breakfast provided up to a third of daily energy requirements, as well as some fibre and whole grains.

Examples included porridge, wholegrain bread, eggs and low-fat yoghurt.

"I would rather my kids had porridge with a teaspoon of brown sugar than white bread with just margarine."

While some mueslis were high in sugar, they also provided fibre, proteins and vitamins.

Buying muesli in a Wellington supermarket yesterday, Sandra Muller, 26, said she was aware the cereal could be high in sugar and fat.

Ms Muller, who had studied nutrition, said she took muesli off her husband's diet while he lost weight. "But he lost some, so now he's allowed it again!"

Winston Muller, 24, said he previously had no idea that some mueslis were high in fat and sugar. "I actually used them for meal replacements, and I wondered why I wasn't losing weight."

Cereal maker Hubbards said the Consumer survey was accurate. "We're pleased it has highlighted several of our products that have lower-than-average fat and sugar content."

MUESLI NOT ON PRISON MENU

Prisoners are served a healthy breakfast - and muesli is not on the menu.

Hospital patients, on the other hand, may munch on muesli if they please.

An example of a standard prison breakfast was two Weetbix with milk, three slices of toast with spread and a cup of tea.

The prison menus were developed with input from the Health Ministry, Diabetes Life Education and the Heart Foundation in consultation with a clinical dietician.

Corrections spokesman Russell Baker said: "Prisons have eight different menus catering for normal meals, and a variety of specific requirements such as low-fat, vegan and diabetic for both male and female prisoners."

Capital & Coast District Health Board chief operating officer Chris Lowry said there was no standard breakfast for hospital patients, as many were on special diets.

A low-fat natural muesli was one of six different cereals available on the standard breakfast. "Our biggest concern for hospital patients is ensuring they get enough to eat while they are unwell, so an occasional choice of muesli as part of a balanced diet would not compromise their health."

The Five Most Sugary Mueslis

1. Alison Holst Honey Toasted: 30.7 grams of sugar per 100g of product

2. Cec's Homestyle Gluten Free: 30.4g

3. Freedom Foods Muesli Gluten Free: 30.1g

4. Hubbards Fruitful Breakfast Extra Tasty Toasted Muesli: 28.9g

5. Hubbards Thank Goodness Gluten Free Berry Muesli: 26.8g

Source: Consumer Magazine

Grain Foods Toasted Muesli (per 100g)

Fat: 20.7g

Sugar: 17.9g

Salt: 479mg

Nacho cheese flavour Doritos (per 100g)

Fat: 23.9g

Sugar: 4g

Salt: 565mg

- © Fairfax NZ News