I was interested in the discussion on Radio 4 about McDonalds - who have now been in the UK for 40 years. I think it's particularly interesting the idea that they have caused (or at least significantly contributed to) a change of the nation's palette. It perhaps shows how if you don't take control of what you eat, then others will in order to make money out of you!
I do believe that many people do eat too much Salt, Fat and Sugar which both directly and indirectly results in poorer health.
The notion of "fast food" causing a break down in our eating routines, i.e. our meal times, is also pretty interesting. Again, it highlights how easy it is to pawn control of your eating, one way or another, out to commercial and big business interests.