BEIJING – Nothing about the lunch rush at a McDonald’s in China would feel out of place in America: Students huddled around video games and fries; a computer salesman scarfing a chicken sandwich; a teacher lingering over a hamburger and coffee. And in that all-American scene lies the next great challenge to the world’s food supply.

“It was impossible for my parents’ generation to have meat all the time,” said 42-year-old teacher Xue Wei, polishing off a piece of pie. “Now, we can eat meat every day.”

The roots of today’s food crisis span the globe, from sky-high oil prices in the Mideast to the diversion of crops from food to biofuel in the U.S, to drought-stricken harvests in Australia. But the crisis also has focused attention on a longer-term trend: the growing, evolving appetites of developing giants such as China and India.

GROWING NEEDS FOR IMPORTS

“Population is increasing, and the income of the poor is increasing, but production is not increasing,” said Usha Tuteja, head of the Agricultural Economics Research Center at Delhi University.

Rising consumption in China and India are not the prime causes of today’s food-price shocks; both countries are largely self-sufficient in rice and wheat, staples that have fallen short in other developing countries and triggered riots.

But experts see milestones on the horizon: Sometime in the next year, for instance, China’s growing consumption and shrinking farmland is likely to turn the country into a net importer of corn, a major source of animal feed and an ingredient for many of the processed foods cropping up on the country’s supermarket shelves.

Likewise, India is on track to become a grain importer, thanks to a fast-growing middle-class and upper-class minority that demand a diet diversified beyond the traditional staples of grains, legumes and vegetables. Dairy products are in particular demand in a country where at least 70 percent of the population counts itself as vegetarian.

“You can pretty much see India is going to be an importer of grain,” said Arif Husain, a senior food policy analyst with the World Food Programme in Rome. “Increased demand is one of the top reasons why prices of food are going up. And India is a large player in that sense. It’s about China and India, basically.”

CHINESE EATING MORE MEAT

The issue hinges not simply on how much a country is eating, but what it is eating. After struggling for centuries to feed its population, China has succeeded in lifting 400 million people from poverty in the past generation. That achievement has triggered a fundamental change in the country’s consumption of resources.

“A 6-year-old boy in China today is 6 kilograms (13.2 pounds) heavier and 6 centimeters (2.4 inches) taller than he would have been 30 years ago,” said Anthea Webb, director of the World Food Program in China. “That’s a strong indication that people are much healthier and better nourished. For the long-term picture, it does present a challenge.”

China’s per capita annual meat consumption has more than doubled since 1980, to 110 pounds today. That has created unprecedented demand for animal feed. Producing one pound of chicken, for instance, requires nearly two pounds of corn and soybean meal. A pound of pork requires five to seven pounds of feed; beef needs more than 8 pounds.

But China and India are wary of being portrayed as culprits behind a global shortage. When President Bush told reporters May 2 that the rise of India’s middle class fueled price spikes, Indian officials struck back, pointing to their grain surpluses. Likewise, China’s Vice Agricultural Minister Niu Dun declared that “developed countries should bear the main responsibility” for the global food crisis because of policies that have diverted crops for biofuel.

Though China is a top consumer of commodities worldwide ranging from timber to copper to oil, it has long stockpiled grain at levels higher than the standard suggested by the UN’s Food and Agriculture Organization. Indeed, David Dollar, the World Bank’s China director, said China’s role in the food crisis, to date, is “a small part of the picture.”

A report released by UBS economists in September, found that although “Asian affluence” is not yet a dominant factor in global food prices, long-term trends in Asia “seemingly pose a change in food demand of proportions unlike those previously recorded in human history.”

Though India is home to the world’s largest malnourished population, its growing middle class is transforming the nation’s diet. Those changing appetites, combined with population growth just under 2 percent a year and agricultural productivity increases of only about 1 percent a year, mean India could soon begin using its substantial foreign exchange reserves to buy food on the international market. That would further drive up world prices, analysts say.

India might be able to meet some of its growing demand by increasing agricultural productivity at home. The country produces today only half the yield per acre China has achieved, mainly as a result of differences in irrigation, experts say. M.S. Swaminathan, an Indian agricultural scientist, said India’s agricultural production today is only about 30 to 40 percent of its total capacity.

Rising demand and rising food prices have “made Indians realize we have to build our food security with homegrown food, not imported food,” he said.

That realization, which is hitting home in China and India, has resulted in boosted agriculture budgets for both this year. China’s budget has risen by 20 percent for 2008, and India’s by 30 percent, said Joachim von Braun, director general of the International Food Policy Research Institute in Washington, D.C.