[willcipriano]

In a perfect world I'd be able to set a weekly calorie limit. Charge me double the cost and send the overage to the charity of my choice for any food over the limit.

A government body limiting who can buy food isn't really a good idea, so it only works in utopia. It could work for non-essentials though.

[ThalesX]

I order from a service that provides me nutritionist-built meals every day; in the morning, I get exactly 2000kcal spread out across 3 meals and 1 snack. I also drink protein yogurt reaching around 2350kcal so that's my daily intake (and I guess calorie limit) with balanced macro and micronutrients.

What this means is that I am aware that anything above these meals is too much for me. Do I still do it? Yes, but I have an unhealthy relationship with food.

[__MatrixMan__]

What if you could opt for a custodian, and the designation can't change very often (like open enrollment)?

Give a trusted friend the right to set your calorie limit, and if it doesn't work out, try a different friend next week--but you can only change it between 10AM and 2PM on Mondays.

[willcipriano]

Yeah I could see maybe a credit card sort of offering with these rules. I don't think credit cards get that granular level of data however. Then I would only have to commit to only carrying around that card.

[__MatrixMan__]

Yeah, let's not hand that sort of data to the credit card companies. It might be a good use case for homomorphic encryption--where the transaction processor computes a go/no-go result without knowing why (and then you scan a QR code and decrypt on your device).

I was thinking of having it decoupled from payments, sort of a more customizable replacement for the ID-checks that we currently do when buying alcohol. I think you could do zero-knowledge trickery to avoid the privacy problems.

But then again, an API for a third party to cut off your access to resources might be too juicy of an abuse-enabler to be worth building.