Haven't RTFT. Obesity is a very multi-factored issue.
I've often thought that if people who were struggling could receive a 'larder' parcel that may help to get them started e.g. salt, pepper, oil, a few dried herbs and spices, stock cubes, cornflour. Although writing it down that stuff is very cheap.
Ditto for some sort of national 'kitchen kit', so a couple of chopping boards, sharp knives, peeler, measuring jug, baking trays, a casserole dish, wooden spoon and spatula, frying pan, couple of airtight containers, couple of pans with lids. Again, this doesn't cost a lot but would be a big outlay if you literally had no money.
Also the acceptance that eating both cheaply and nutritiously DOES take time and always has... finding the cheaper cuts of meat, planning, preparing, soaking pulses and grains.
And changing people's tastes - people say they can't afford food - this is worse surely if they are fussy and like only a narrow range of things. If you're unfussy to eat whatever fruit and veg is on offer, you can eat extremely cheaply.
As for exercise, if people can walk, they should - it's free. There are lots of parks in this country where people can go to exercise. There are loads of free exercise videos online. There is loads of recipe advice online. It's never been more accessible. There's cheap exercise clothing everywhere. It just requires the intention to do it.
I'm not financially stuck, but it is easier not to exercise and to eat easy, quick food. It's a whole change of mindset that we need. Cheaper food can be more challenging to cook, eat and store - we have a couple of generations of people now who are used to very bland, processed food and we'll never get past that if we don't do something. The thing is, a small cox's apple or two digestive biscuits for a snack doesn't really make any money for anyone. Snack-a-jacks and Special K bars do.
Being healthy is not something that someone can do for you. We have to help people to want to do this for themselves. Whilst we push 'gyms and salads' that's a very unappealing message. I'm convinced that the waitrose / boating like types are largely like that not only because they're better off, but because healthy choices in terms of snacks / alcohol / basic foods are simply a way of life.