Taxing something that's bad for you is not such a bad idea, wrote Rudy Ruiz in an opinion piece that refers to the work of Gary Foster, director of Temple University's Center for Obesity Research and Education. Foster found that Philadelphia children can spend $1.07 in a corner store and emerge with 360 calories, mostly from sugary drinks, chips, and candy. "If we could change what kids eat by 100 calories a day," Foster said, "those kinds of small changes are whopping."