The comments come close on the heels of US Secretary of State Condoleezza Rice's controversial statement that ‘apparent improvement’ in the diets of people in India and China and consequent food export caps is among the causes of the current global food crisis.

At an interactive session on economy in Missouri, Bush argued that there are many factors for the present crisis, only one of which was investment on biofuels like ethanol.

"Worldwide there is increasing demand. There turns out to be prosperity in developing world, which is good. It's going to be good for you because you'll be selling products in the countries, you know, big countries perhaps, and it's hard to sell products into countries that aren't prosperous.

In other words, the more prosperous the world is, the more opportunity there is," the US President said. "It also, however, increases demand. So, for example, just as an interesting thought for you, there are 350 million people in India who are classified as middle class. That's bigger than America. Their middle class is larger than our entire population.

"And when you start getting wealth, you start demanding better nutrition and better food, and so demand is high, and that causes the price to go up," he said.

Bush also listed change in weather patterns and increase in basic costs like that of energy as factors contributing to higher food prices.

"No question that ethanol has had a part of it. But I simply do not subscribe to the notion that it is the main cost driver for your food going up," Bush said.

Several international experts have in recent days held biofuels, until recently cast as a miracle alternative to polluting fossil fuels, for being responsible for usurping arable land and distorting world food prices.

"Actually, the reason why food prices are high now is because, one, energy costs are high, and if you're a farmer, you're going to pass on your cost of energy in the products you sell, otherwise you'd go broke.

"And when you're paying more for your diesel, paying more for your fertiliser because it's got a lot of, you know, natural gas in it, in other words, when your basic costs are going up, so does the cost of food," Bush said.

He said there are two aspects of rising food prices -- its effect on US citizens and the fact that there is a food scarcity in the world.

"We don't have a scarcity issue in America...We got a price issue. Our shelves aren't going empty, it's just costing more money," Bush said. "There is scarcity in the world, and I happen to believe when we find people who can't find food we ought to help them find it," he said adding, "America is by far the most generous nation when it comes to helping the hungry."