This week, a coalition of food and beverage manufacturers -- including Campbell Soup, Coca-Cola, General Mills, Kellogg, Kraft Foods and PepsiCo -- signed up for First Lady Michelle Obama's campaign to reduce childhood obesity within a generation. Pledging to cut portion sizes and trim calories in current products and introduce new, more healthful options, they estimate they can slash 1 trillion calories by the end of 2012 and 1.5 trillion calories by the end of 2015. "This is precisely the kind of real private-sector commitment that we need," the first lady said at a news conference at the Eisenhower Executive...