PHILADELPHIA - Some of the fattest people in America are among the poorest.

And with food prices rising, the problem is likely to get worse.

Tianna Gaines, who describes herself as impoverished and obese, knows this. At 5-foot-3 and 242 pounds, she lives on public assistance and eats junk food because it's cheap and more readily available in her neighborhood than carrots and apples.

Besides, said Gaines, 28, and a mother of three, "I don't have the money for Bally's fitness clubs. And I can't run here. They shoot you."
 
More poor people may suffer Gaines' fate, with the U.S. Department of Agriculture predicting food prices will be up 4.5 percent throughout the year, due to high fuel costs, weather problems, and the growing diversion of corn crops to make ethanol. Globally, prices will rise nearly 50 percent, according to the president's Council of Economic Advisers.