AS MUCH food is wasted in developed countries as is produced in sub-Saharan Africa.

This ''eye-popping'' statistic highlights one of the big changes urgently required to meet the challenge of feeding 9 billion people by 2050, a visiting expert in agriculture and economics has said.

Chris Barrett, of Cornell University, warns there is ''dangerous complacency'' about global food security. Professor Barrett, who will give a public lecture on Wednesday night at the University of Sydney, said that demand for food is about to rise significantly, particularly as a result of population growth in developing countries, rises in income and the migration of people to towns and cities.

There is no magic bullet with which to meet this unprecedented demand, which will be for animal products, processed foods, fruit and vegetables, and traditional staples, he said.

''We need a multipronged strategy to ensure our grandchildren's generations do not confront chronic global food crises of the sort that our grandparents' generations so skilfully averted on our behalf.''