I know that potatoes are high on the glycemic index, and red potatoes are slightly lower than normal potatoes. I've seen online that boiling red potatoes and eating them cold the next day drops there glycemic index level from 85-90 all the way down to 56! It supposedly has something to do with molecules arrangement when cooled and full of water for a while. I'm kinda sceptical, because i haven't seen the same for other carbs. Do u guys know anything about this? Also, can I reheat them in the microwave p, or will it disrupt the molecules and raise its glycemic rating back to 85? But is this all just 'bro science,' or is it legit? Thanks!
Marcus,
If you are going to eat potatoes, Sweet potatoes are the better potatoe to eat. They are much more nutrient dense and don't affect blood sugar as much as regular potatoes.
As for your question, this is true. Potatoes contain starch and starch is made up of 2 molecular components - Amylose and Amylopectin. Foods high in amylopectin in relation to amylose (like potatoes) tend to have higher GIs. When you boil a potatoe, the amylose and amylopectin gelatinize - convert to glucose. This will increase its GI. However when potatoes cool after being boiled, they go thru a process called retrogradation. Retrogradation is when the amylose and amylopectin start to return to their normal macro-molecule states thus not being as gelatanized and therefore having less glucose which lowers GI.
John
