If you take a multivitamin, I don’t see why you couldn’t live off of it indefinitely. It does probably have enough vitamins for you anyway. Is that really a life worth living?
The fictional version of it is apparently named after soy and lent (the religious fasting thing, I guess), TIL. But the real-world version literally has meal replacement in the Wikipedia page title. Was looking for a reference from the creator stating their goal but Wikipedia said unreferenced (at the time that I wrote the Dutch translation in 2014) that it's supposed to be nutritionally complete. The English page was shortened considerably since then, dunno why but this part is gone. That's how it started and was marketed though, so that's what makes it that by definition in my mind. If they've strayed from their raison d'être, idk what they are anymore