Please don't take this the wrong way. I mostly agree that we eat junk. And I believe that we as a society have to deal with that. But see what I strongly believe in at economic level.

Specialization (and division of labour) is not the same thing as central planning.

Even if food supply was monopolized (it's clearly not) it doesn't mean central planning. Concurrency is still possible (well that may change in EU soon enough through regulations).

better specialization allows the society to be more productive and accumulate capital to raise (more) people from poverty.

Only at that point you can start the demand for better (more expensive) products.

That's where the west may be at the moment. That's why you can choose.

However, you can't take cheep food away from the poor. And yes, without processed food and  synthetic fertilizers millions will die of hunger (see what happened on Sri Lanka recently).

Decentralization as you refer to it is a regression of labour division. And a step to lower production. And inevitebly hunger.

You can't tell if it's better to save on food and live longer or healthier (or whatever) for anybody but you. It's a subjective value.