Low-carb diets, the demise of the McDonald's Supersize menu, and even mad cow disease have hurt the market for potatoes, so spud growers are fighting back. "The National Potato Promotion Board (NPPB) recently launched a $4.5 million campaign that mixes print advertising, public relations and partnerships with weight-loss groups to educate consumers about the healthy benefits of potatoes," reports the Associated Press. According to NPPB president Tim O'Connor, "There's nothing anyone can do about McDonald's deciding to eliminate its Supersize. ...