New research shows that teenagers are spending lunch money on cheap junk food to free cash to top up their mobile phone credit.
The research from University College Cork (UCC) also shows teenagers are eating high-fat food and drinks such as Coke, crisps, chips and chocolate, up to four times during a school day.
The survey of almost 1,500 students in six Cork city and county schools was undertaken by Dr Mary McCarthy and Dr Alan Collins at the UCC department of food business and development.
The findings reveal that almost one-third, or 32 per cent, of parents don't know or care how their youngsters spend their lunch money.
According to the researchers, parents are financing the consumption of energy-dense, nutritionally poor foods because of convenience and/or pressure from youngsters to conform.
Almost 30 per cent of students surveyed were in receipt of lunch money every day and choose what they bought and ate.
Almost 60 per cent brought a packed lunch to school at least four times a week.
Dr McCarthy said top-shelf food and drinks were perceived to represent better value with teenagers who use left-over cash to purchase other products such as mobile phone top-ups.
"If you are a secondary school student on a budget, you are going to choose cheaper food products that give you an instant feeling of satisfaction.
"This gives you money to buy a top-up for your phone," she said.
The findings show that where top-shelf food and drinks are readily available, either on school premises or in accessible outlets, consumption was found to be higher.
Most schools were found to be involved in providing food for sale via canteens, vending machines and tuck shops.
Dr McCarthy said teenagers are being given responsibility for themselves at an earlier age, often resulting in poor dietary choices.
"On a positive note, not all of them have lunch money available to them but those who do are buying an average of four top-shelf food items during the school day," she said.
"It sounds like a lot until you break it down to a can of coke, a bar of chocolate, a bag of crisps and some sweets. That is a lunch for many pupils.
"Things aren't that bad in this country, but our trends are towards greater levels of obesity."