I liked this last part of the article the best but be sure to read the whole thing...
The Wal-Mart effect shows, finally, how incentives matter. We've illustrated how changes in relative prices and purchasing power affect people's decisions, and this research suggests that people do make the right decisions when the prices of healthy foods fall and purchasing power rises.
Do you want to make poor people healthier? Then restricting the growth of discount chains is the last thing you should do. Instead, repeal programs that distort incentives--like agricultural subsidies that make junk food made from corn and soybean derivatives artificially cheap. Next, cut payroll taxes. With more take-home pay in their pockets, lower-income workers can afford to buy foods that are better for their health.
I bet there is a correlation in there for 'poor communities' looking for new economic development opportunities as well. Think about it.