Hmm.
I think it is actually quite sensible to try to get people to take responsibility for themselves - but it could be backed up in the school curriculum and school canteens!
Get rid of the fast food shite that is served, bring back proper food school dinners; no "tuck shops" or Coca Cola vending machines and TEACH the children about nutrition and cooking properly.
The incentives for exercise should be improved massively - yes to extra cycle lanes but STOP the loss of cheap/free exercise and leisure facilities. In my old town in the UK, we had a school that had sufficiently good gym and sport facilities (including an open air swimming pool) that it could be used by people outside the school, for a £12 annual membership and a pay-per-visit fee (about £3). This was then revamped by the Council and turned into a Leisure complex (still part of the school) that involved a £600 annual fee (and probably no pay per visit) - which effectively removed it from most local people's access. Now THAT was pathetic.
Tennis courts in our town were pay per use; the ones in the next town were free. The ones in our town were always empty - making these things free to use might encourage people onto them a little more.
Having more open/easy access sport clubs etc. would help - but people have to become used to doing the stuff AT SCHOOL - so STOP the sale of school sports fields for development!!
Sort out the allotment situation - MAKE every school have a vegetable garden that the children help out with, and they might even manage to supply some of their own veg for the proper school dinners.
"Fat tax" is hopeless. All it will do is encourage more 98% fat-free-but-laden-with-other-shite-including-extra-SUGAR-to-make-it-edible diet foods - since the explosion of these diet foods onto our supermarket shelves, people have got noticeably fatter, not the opposite! Sugar is a real problem - if you want to tax any food group, let it be sugar and the added sugar family that isn't always immediately obvious (dextrose, HFCS high fructose corn syrup, partially inverted dextrose syrup etc. etc.) Agree that artificially altered fats are bad - trans fats and hydrogenated vegetable oils - they should be reduced too.
Encouraging outdoor thinking more - so many people seem to think they will melt if there is the slightest hint of rain (it's exactly the same here in Australia) so the only thing people do is sit indoors or go shopping in vast covered malls, with fast food outlets every couple of hundred metres.
Get rid of drivethrough fast food places as well (ideally I'd like to get rid of them completely but they have their place) - make people get up on their feet for at least 5 minutes to get their stuff!
Agree to getting rid of the advertising - increasing the cost of fast food would be a good plan too. If you have a system where raw ingredients cost more than a burger-inna-bun, people on low income are going to choose the burger-inna-bun more often --> overweight and unhealthy tendencies.
Those are some of my thoughts on the matter. I'm sure I could think of a load more given half a chance but I need to go and have breakfast.