As a treat I will have the odd teeny tiny portion of 'resistant starch' method, with potato, sweet potato, and pasta is just a swiped spoonful. No spike as the quantity, and usually drowned in healthy fat, is so small, is my understanding. I wouldn't risk or even bother testing for an actual meal of it! (But I was diagnosed with an HBA1c of 93.)
I am really carb intolerant (surprise! on a diabetes forum), but in my opinion and experience, who really gains from this is folk with only slightly 'into the orange' HBA1c, and therefore not so dire dysregulation, that tweeks of this nature allow them to eat what someone like me cannot, and still have healthy HBA1c's.
I really recommend this 'cook, cool, reheat' method of dealing with those carby foods to folks wanting to prevent diabetes, or control a tendency to be prediabetic. Then this resistant starch thing is a godsend!