by NANCY SHUTE Hajime Ando / Flickr Putting the shopping bags in the bike basket rather than in the car trunk could deliver big health benefits. What would you say to a cheap, easy way to stay slim, one that would help avoid serious illness and early death? How about if it made your neighbors healthier, too? It could be as simple as biking to the store. Researchers at the University of Wisconsin were wondering if getting people out of their cars just a wee bit would create measurable improvements in health. So they gathered up data sets on obesity, health effects of pollution, and air pollution caused by automobiles in 11 Midwestern cities, and did a mashup. They found that if the Midwesterners ran half of their short-distance errands by bike rather than by car, 1,100 deaths would be avoided each year, and $7 billion would be saved in reduced health-care costs. The trips were 2.5 miles one way; less than a 25-minute bike ride, the researchers figure. The be