I think the best approach to this whole idea is to understand it’s a national problem, but to address it on an individual basis.
I.e. if I watch (or watched – I was at Legoland yesterday) a morbidly obese family all tucking into full-fat coke, double burgers, large fries, piles of ice cream, crisps, sweets, and so on. And this pattern is likely to continue day in day out. Then this particular family should address their weight/health concern via diet mostly.
It’s the equivalent of me constantly smacking a hammer against my head, complaining I have a headache, but feeling helpless as “recent studies have shown that in some cases, headaches are caused by a rare genetic mutation that simply cannot be fixed”…
DrP