The broadcasting regulator is sticking to its plans to ban junk food ads during TV shows watched by under-16s.
The restrictions focus on foods high in salt, fat and sugar
Ofcom has concluded a consultation on its proposals for restricting ads for foods and drinks which are high in fat, salt and sugar, published in November.
Health campaigners had wanted a ban on junk food ads up to the 9pm watershed.
But Ofcom has said the ban, which will be phased in, will cover any shows teenagers will find appealing, whenever they are aired.
Ofcom had already said there would be a total ban on ads during children's programmes and on children's channels, as well as adult programmes watched by a large number of children.
After the consultation, it has been decided that the timetable will be:-
- 1 April 2007 - ads for foods high in fat, sugar and salt will be banned during or around programmes made specifically for children or those which would particularly appeal to children aged seven to nine,
- 1 January 2008 - junk food ads will banned in and around programmes aimed at, or which appeal to, children aged four to 15,
- By December 2008 - Dedicated children's channels will have to have phased out all junk food ads.
It has been estimated the ban will cost broadcasters an estimated £39 million in lost advertising revenue.
Ofcom also said there would be new rules governing advertising to primary school age children.
The use of celebrities and characters, such as cartoon heroes, free gifts and health or nutrition claims will also be banned.
Ofcom suggests the package would mean that, in households where children's viewing includes a large number of programmes targeted at adults as well as those for children and young people, under-16s would see 41% fewer junk food ads.
A Food Standards Agency ratings system will be used to assess which foods are too high in fat, sugar and salt to be advertised to children.
Ofcom will review the effectiveness of the restrictions in the autumn of 2008.
But Ofcom's plans have come in for criticism.
Peter Hollins, chief executive of the British Heart Foundation, said: "Despite all the evidence, Ofcom have turned their back on the right thing for the nation's children.
"We are hugely disappointed that they didn't take the ban a step further in the first place.
"A pre-9pm watershed ban is the best way to protect our kids and is what parents want to see happen1. It's time for the government to step in."
And Melanie Leech, director of industry body the Food and Drink Federation, said: "Ofcom notes TV advertising has a modest, direct effect on children's food choices and is only one among many influences.
"So today's decision will not, by itself, reduce childhood obesity; there are no silver bullets that can be fired at this particular problem."
She added: "We are disappointed that Ofcom has decided to extend the restrictions on advertising to cover young people.
"This is a disproportionate response given that the issue has always been about young children, and industry responded to Ofcom's initial consultation on that basis."