Monica Reinagel had no background in broadcasting or radio when she launched a podcast called Nutrition Diva in 2008, but she was a trained nutritionist, had published several books, and was writing a regular column at a popular health website, and this was just the sort of background that Quick and Dirty Tips, a podcast network run by the book publisher Macmillan, was looking for when she reached out to it to ask if the company would consider taking her on.