No, not that Soylent - this one isn't people.
Random nerd decided it would be nice to make a shake that stores well and provides 100% of nutrition - something you could live on. The recipe and discussions with nutritionists went open-source and variants sprang up. There are many reasons it's a neat idea, from the original "I just want default_food without it being crap" through to the zombie apocalypse and parallels with plumpy nut.
So, I had to give it a try.
Here's a recipe (there are
many more). It's a perfectly palatable oaty smoothie, especially made with vanilla protein.