Yes, and potatoes, rice, pasta, Bread, and most fruit.
Not always. Sometimes the way you cook and serve foods makes a huge difference on a person's blood sugar readings.
One interesting fact is that if you say fully bake a small Russet potato, and then refrigerate it for a day, then briefly reheat it for the next night's dinner, you have dramatically lowered it Glycemic Index. The cooking, then cooling then slight heating changes the starch molecules and how the body processes them.
Cooking really is chemistry in action, if you look at it the right way. Enjoy the following scientific study Abstract in the URL link. Lots of fruits and some breads are not as bad as they are normally thought of, again, how the ingredients are processed and then made into the final product makes a huge difference.
“....eating cooled or reheated potatoes reduces their GI by 30–40%. The aim of this study was to see if cooling and reheating had the same effect on the GI in different potato varieties. Thus, we determined the GI of four different types of potato, each of which was boiled and served in 3 ways: freshly cooked, cooled and served cold, or cooled and reheated. ANOVA showed, no main effect of potato variety, but a significant main effect of cooling with cold potatoes having a lower GI than freshly cooked or reheated potatoes (P<0.05). However, there was also a significant cooking*variety interaction, with cooling having a significantly greater effect in one variety than two of the others (P<0.05). We conclude that the effect of cooling and reheating on the GI of boiled potatoes differs in different varieties.....”
https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.24.1_supplement.553.2