A global campaign aimed at reducing the marketing of unhealthy food to children has been launched.
More than 50 consumer groups are backing a voluntary code of practice which includes tight restrictions on television and internet advertising.
It also calls for a ban on unhealthy food promotion in schools and an end to the use of celebrities and cartoon characters.
UK food manufacturers said removing adverts was no "silver bullet".
World Health Organization figures suggest that up to 177m children worldwide are threatened by obesity-related diseases, and it is predicted that 2.3 billion people over 15 years old will be overweight by 2015.
The new measures have the backing of the London-based International Obesity Task Force, which says that the several billion pounds spent each year advertising food or soft drinks is partly to blame.
Its chairman, Professor Philip James, said: "It is vital that, as well as governments, food industry leaders support the new standards we propose.
"We challenge the giants of the food and beverage industry to throw their weight behind this and demonstrate they really do want to be part of the solution, not part of the problem."
The code concentrates on foods high in fat, sugar and salt, and, in addition to a ban on advertising between 6am and 9pm, asks for a complete halt to internet and new media advertising, and no use of celebrities or cartoon characters, competitions or free gifts.
Sue Davies, the chief policy officer of Which?, one of the 50 groups, said: "With rising rates of obesity and diet-related disease escalating globally, food companies need to take a more responsible approach to the way they market their foods to children, whichever part of the world they are trading in."
In some parts of the world, including the European Union, there are some restrictions on marketing.
The UK television regulator Ofcom introduced a ban on marketing unhealthy foods in adverts during shows aimed at children. This came into force in January.
A spokesman for the Food and Drink Federation, which represents the UK industry, said: "As far as marketing in the UK is concerned, we are now one of the most heavily-regulated markets in Europe.
"As a result the marketing landscape has dramatically changed recently - for example in addition to the new regulations, many of our leading member companies are developing new codes of practice or strengthening their existing ones.
"These codes of practice apply to products popular with children, and the codes are implemented globally.
"Restricting advertising of food and drinks to children is not the silver bullet to solve the complex issue of obesity."