Mark Bittman is a high-profile figure in the United States. He's the chief food writer for the New York Times, a broadcaster, and a bestselling author.Keen to understand the differences between the British and American food systems, one day he made a call out of the blue to Sheila Dillon. Once in London, he fixed up meetings with Jamie Oliver, Hugh Fearnley-Whittingstall and Arthur Potts Dawson.The Food Programme joins Mark on his personal journey into the world of the campaigning chef.Produced by Rich Ward.