Do you know what your child is eating for breakfast?

Students are shunning toast and cereal for breakfast in favour of fried chicken, and chips, pies and fizzy drinks - a habit nutritional experts say is as dangerous as smoking or alcoholism.

Despite banning junk food from tuckshops, schools appear powerless to stop students buying breakfast on their way to school from dairies, takeaway bars and fast-food outlets like McDonalds.

And it seems few parents - especially busy working parents - have any idea what their children are eating.

A Herald on Sunday investigation found takeaway breakfasts washed down with two-litre bottles of soft drink were the norm for students at six Auckland secondary schools.

De La Salle College students eat about 6kg of fried chicken drumsticks every morning, Rangitoto College pupils prefer energy drinks and McDonald's, and Avondale College students buy 1600 pies and 1200 cans of soft drink from one dairy in the area every week.

The Herald on Sunday also found students from Auckland Grammar and Epsom Girls Grammar tucking into McDonald's, pastries and 1.5 litre fizzy drinks at 8am.

Jim Mann, professor of human nutrition and medicine at Otago University, called the trend an "epidemic".

He said if the Ministry of Health's plans to educate the public about healthy eating did not work, it should press for legislation to ban junk food advertising aimed at children, he said.

A new University of Auckland study showed that on average, students who ate takeaway breakfasts were at least 2kg heavier than schoolmates who ate breakfast at home.

Those who drank at least one soft drink a day were also 2kg heavier than their healthier peers.

Nutrition expert Sarah Ley said the fat-laden breakfasts meant students risked diabetes, heart disease and strokes.

A chicken and chips breakfast would provide double the calories and perhaps three times the fat of a typical breakfast, said dietitian Victoria Nealie.

"Obviously, they are also missing out in terms of sufficient fibre ... the vitamins and minerals and calcium and things like that."

But students interviewed by the Herald on Sunday said they did not like cereal and had no time for breakfast at home.

"It tastes good, we don't think about our health, we just go for taste," said 16 year-old St Peter's College student Orlando Brown-Esera. He and his friends ate at the Newmarket McDonald's every morning. Duty manager Shuyi Zeng said up to 80 children - some of primary school age - bought breakfast there every day.

BP Newmarket manager Matt Eagleson said students ate "pies, Cokes, chips, chocolate, every single day" for breakfast.

On Friday morning, every checkout in the Foodtown supermarket in Newmarket mall was packed with secondary students.

Doughnuts and danish pastries sold out in the bakery section, while big packets of chips, chocolate and biscuits were a staple part of breakfast.

Customer service manager Shobna Lal said students bought whatever soft drink was on special, usually the large 1.5 litre bottles.

Green Garden Takeaway owner Janif sold 6kg of fried chicken from his shop outside De La Salle every morning.

He said breakfast was his busiest time of day - the rush started at 7am and he estimated about 100 boys filled up on his $2 chicken-and-chips breakfast special.

Robert Scragg, childhood obesity expert and director of the Pacific Obesity Prevention in Communities project, said: "Ultimately, it's parents who have a big influence on what kids eat; parents are critical."

Avondale College principal Brent Lewis was amazed that more than 11 per cent of his 2700 students ate pies and fizzy drinks for breakfast every morning.

The school canteen was junk food-free and students were educated about healthy eating.

Annette Sharp of Epsom Girls' Grammar said Auckland traffic meant parents left for work early and didn't have time to push the "cereal or egg on toast" message.

St Peter's College principal Kieran Fouhy said boys, in particular, would always take a pragmatic approach to food.

"It's about taste and convenience and price. That's why they have to be educated about healthy foods."

-HERALD ON SUNDAY