This could lead to a ban on TV ads aimed at children if the food and ad industries fail to curb their campaigns for sweets, soft drinks, snacks, sugary breakfast cereals and fast-food chains, MPs warned.
One minister said: "We do not want to impose a ban, but we will consider one if the industry doesn't put its house in order."
The Government will hold talks with Ofcom after an academic study carried out for the Food Standards Agency suggested a link between advertising and unhealthy diets.
Professor Gerard Hastings, who led the research at the University of Strathclyde's Centre for Social Marketing, said: "Advertising to children does have an effect on their preferences, purchase behaviour and consumption and these effects are apparent not just for different brands but for different types of food."
The Labour MP, Debra Shipley, who is demanding a ban on food ads targeting the under-fives, said: "This independent report is a damning indictment of the advertising industry's marketing strategies to children."
Research by Nielsen Media Research for the FSA found the amount spent on food ads rose from £359 million in 1994 to £452 million last year.
The top ten spenders last year were McDonald's (£42 million); Coca-Cola original (£15.5 million); KFC (£15.1 million); Burger King (£11.1 million); Pizza Hut (£9.3 million); Diet Coca-Cola (£7.3 million); Pringles (£6.7 million); Kit Kat (£6.4 million); Weetabix (£6.3 million) and Kellogg's Corn Flakes (£6.2 million).
The ad industry argues that Britain has one of the strictest codes of practice on food ads in the European Union.