If it's a local currency this can be considered a local Consumer Price Index. If you peg the local currency to it, the local currency is always available to buy the food, based on the local CPI of necessary goods, regardless of shortages etc. (if the pegging is daily).
Awesome, thanks. It sounds like you're working on some of the ideas I've been mulling over this week. I like the idea of localizing the currency and having immigration restrictions. Localizing helps solve the problem of scaling pseudonym parties. Finding a world-wide, or even nation-wide time where everyone can show up in a group in order to verify their personhood would be tough.
I guess the next issue is how do you take that CPI, adjust, and issue currency in a decentralized / consensus way. Also, how susceptible to manipulation would these schemes be.
I would love to see a more economically sound cryptocurrency, rather than the deflationary mess that is Bitcoin.
Related to deflation - I believe there are demurage schemes for local currencies where the value of a particular bill lessens over time. It incentivises circulation instead of hoarding.
I had a similar scheme for local based UBI here: https://qbix.com/blog/index.php/2017/09/the-future-of-money/