(CC BY-SA 2.0) Terry Ross/Flickr There was a dramatic development in the world of Big Soda last month. PepsiCo announced the first major reformulation in its Diet Pepsi brand in some thirty years. As of August, the company will replace the artificial sweetener aspartame with the artificial sweetener sucralose. The change is not being made for purposes of improving the beverage’s nutritional content, which will remain approximately zero. And it’s not being made because the Pepsi people think aspartame is harmful. Pepsi has always claimed it to be utterly benign, and the federal government has the company’s back on this: according to the Food and Drug Administration, aspartame has been the subject of more than 100 studies that have repeatedly found it to