but cost is a BIG part of it for some people...
actually as a single mum on benefits I think its fair to say that I can comment on this, 6 months ago, after watching 'jamies school dinners' , my sons and I figured well if he can do it for 37p per head we should be able to do better than we were budget wise, so we changed our shopping/eating habits totally.
we no longer buy vegetables or meat from supermarkets at all, we buy no processed food at all, apart from co-op sausages

( its the skins, I prefer the skins!!! so shoot me), tinned food of course and cleaning products, have to come from there, but not meat, fish or veg ( apart from the sausages ok!!)
all in all, my 'food' bill is £25 a week for the 3 of us, we dont eat meat every day, we have fish which I have to walk two miles to get from the local fish mongers ( we live by a fishing harbour so its fresh daily), meat is from my local butchers ,and although I cant afford organic, I wish I could, I do buy free range, and british only, my eggs I get from my dad, at 60p for 6, totally free range and organic with the poop still on them

and fresh veg from the local greengrocers, as much as possible locally grown and organic.
oh and a chicken, lasts us 3 meals, so to all those whinging they cant afford to buy free range ( as opposed to the more expensive organic) BULLparp, we even make our own pasta and pizza with all fresh stuff.
admittedly I would like to buy totally organic, but the cost would be beyond us, however we can still afford to be discerning about what we buy and where from, it just takes a bit more effort and forethought, but its well worth it.