I can definitely see the tangential similarities, but without much else to go on, it seems like Nutraloaf was explicitly created to have the minimal nutrient requirements while also being explicitly unpleasant for inmates. Soylent, by most accounts so far, is at least relatively bland to rather pleasant, with the added bonus of having a complex enough flavor that it doesn’t get old.
As far as soylent as a prison food goes, I don’t really see an issue with it either (though as I typed this @Lisa chimed in with only partial replacement idea, which I can definitely agree with!) With enough long term data (I would say after a minimum of a phase III clinical trial), it’s not only cost effective, but also could end up helping those incarcerated have a more nutritionally complete diet.
@J_Jeffrey_Bragg: I understand your qualm of ‘depriving [people] of regular, normal meals,’ but for all intents and purposes that’s pretty much what soylent is, it’s just in a different form. (my previous point wasn’t really relevant, hence the edit).
I’m not sure if the topic was made with an ‘ideal world scenario’ in mind; one where the prisons aren’t packed and privatized, and where incarceration rates go down instead of sky rocket. But at that same token, in an ideal world scenario, we probably wouldn’t be here discussing trying to extract a meaningful, complete, and cheap diet out of powders and vitamins.