We know that both smoking and obesity can contribute to an early death. In fact health professionals are now telling us that junk food is even worse than tobacco. But do the parallels between the two industries run deeper than that? They have both been accused of cynical marketing, powerful lobbying and trying to avoid regulation. Some people have even suggested big food is taking a leaf from the big tobacco playbook. Manuela Saragosa asks whether junk food is the new smoking.