Most of us eat sweet potatoes... do you find blood sugar differences depending on your cooking method?
This study is pretty interesting
The GI varied between 41–93 for the tubers studied. Samples prepared by boiling had the lowest GI (41–50), while those processed by baking (82–94) and roasting (79–93) had the highest GI values.
Would this change your preparation methods?
Does this effect the 'safe starches' argument?
Especially if you add in a bunch of grass-fed butter to the boiled sweet potatoes? A GI of 41 without butter, I'm sure a big hunk of butter would bring it down to the low 30s.
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The mini sweet potatoes I buy literally ooze with caramelized sugary sweet goodness after roasting in the oven. Top them with coconut oil or butter, and enjoy a little taste of heaven. GI value be damned.
Higher oven temperatures over stove-top boiling may cause breakdown of more starch. More starch converted to glucose means a higher GI.
I've experimented with boiling vs. microwaving. Boiling definitely produces lower BG. When you microwave, you basically suck out all the moisture from the sweet potato and make it more dense. It's about 30% less volume. So it's no brainer. When you boil, you're increasing the volume with water, which stays in the sweet potato, thus diluting the net carbs of the pre-boiled sweet potato.
The effect is the same with potatoes, yuca and yams.
Baked or boiled? Fried. In my bacon grease.
This makes sense to me...the sugars concentrate the most when roasting, that's why they taste all carmelized and yummy. I don't eat very many sweet potatoes, so I'll stick with roasting in plenty of delectable fat.
I vaguely remember an episode of Cook's Illustrated that involved braising sweet potatoes in cream rather than boiling them in water. Their rationale was something along the lines of sweet potatoes boiled in water absorb (or hold onto) water, resulting in a poor texture when mashed. Perhaps this explains the lower GI as well?
Re the "safe starches" argument, I think Paul Jaminet makes a very good case for the various other factors affecting GI, so I'll stick to roasting sweet potatoes and just making sure that the rest of my meal compensates!
I think the potatoes will retain more nutrients if baked. I'm not sure how much of the nutrients are lost when boiled, but I do know that some of them are leeched into the water when boiled.