The study will be launched just seven months after Ofcom's rules for broadcast ads took effect in April, and only four months after the Committee of Advertising Practice code for non-broadcast ads is implemented in July.
A total of 231 MPs, including 149 Labour members, have signed a Commons motion seeking a 9pm watershed for junk-food ads. Caroline Flint, the health minister, said: "We will monitor the impact of the restrictions to see if they deliver our commitment to changing the nature and balance of food and drink advertising to children. The department has committed to work with Ofcom and industry partners on a more detailed review in 2008."
Baroness Peta Buscombe, the chief executive of the Advertising Association, said: "I would urge campaigners and politicians to focus on the root causes of obesity."