Baking can take a long time. I like making a mash by cubing, steaming, and then mashing, and mixing some Adobo sauce for a spicy sweet potato mash!

I thought you had to bake them extra long to turn them high glycemic, other wise it still a slow acting carb.  I ve read that on the forums.

EXACTLY!    DO NOT boil them.  BAKE THEM!  Sweet potatoes when boiled are very low GI, when baked they reach upwards of 70-80 on the GI scale, versus 30-40 when boiled.Wrap in foil and bake at 425 for around 50-70 minutes, or until soft in the center when pierced with a knife. Baking breaks down the sugars and allows them be absorbed faster, hence higher GI, thats why they are much sweeter after baking versus boiling, and why you get all that caramelized gooey syrup that oozes out after they are baked.

To make sweet potatos the most glycemic, bake them whole for about an hour or longer.  Boiling them is not the best option.