The two companies have been in a joint venture since 1990 to sell Nestlé branded cereals such as Cheerios in more than 140 countries outside the US and Canada, markets which account for about $25-billion in cereal sales - about half of total global sales.

They say they will reformulate 20 cereal brands popular with children and teenagers by 2015, boosting whole grains and calcium, and aiming for average reductions of 24% in sugar and 12% in sodium.

The reformulation will affect about 5.3billion portions of breakfast cereal a year.

The 50/50 joint venture, called Cereal Partners Worldwide, is the second-biggest breakfast cereal producer after Kellogg.

Cereal Partners Worldwide CEO Jeffrey Harmening said the plan builds on efforts started in 2003 to improve the nutritional profile of cereals.

The group has cut almost 900t of salt and more than 9000t of sugar from its recipes since then.

"A certain number of mothers don't want their kids to have as much sugar as they do right now, so that is a barrier for some to purchasing breakfast cereal," Harmening said.

The move comes as food and beverage companies try to pre-empt tougher regulation prompted by the global obesity epidemic by offering healthier products or smaller portions.

The World Health Organisation estimated there were over 42million overweight children under the age of five in 2010.

Kellogg - which makes some of the sweetest cereals, according to several surveys - has also reformulated some brands in recent years to cut sugar, as has General Mills for cereals for the North American market.