[cperciva]

rather high GI for soylent thanks to the maltodextrin

That's certainly a concern, although I think the GI has dropped since the initial version thanks to the introduction of oat flour.

But for the purpose of figuring out how all the variables interact, it doesn't really matter if Soylent is good T1D food or bad T1D food... as long as it's consistent. I certainly wouldn't switch to Soylent long-term without seeing how it affects my A1Cs, but as a short-term experiment it might be worth having worse numbers in order to learn how to get better numbers.