Yes they are high in starch, means they get digested quickly and can raise blood glucose levels, so why skip the potatoes and its nutrients for the same reason.
A good idea is to combine it with fiber so their digestion gets slowed down and there is no spike in blood glucose levels hence becomes diabetic friendly. So add all kind of vegetables to it in good amount . To make it an ideal balanced meal add a portion of protein like chicken, meat, fish or eggs.
Another myth is that potatoes are high in calories. No, not really. An average potato has around 150 calories, which is normal. In fact the calories are added the way it is cooked. As the most popular way is french fries and deep frying of potato chips.
Potatoes contain acrylamide. This is a toxic substance found in starchy foods only when they are cooked and processed in very high temperature. It is supposed to cause cancer in lab animals. But nothing has been proved in humans yet. Frying potatoes for long time can result in more acrylamide.
Potatoes are not a no no food for diabetics or obese people. What matters here is the amount consumed and its cooking method.
So enjoy your share of potatoe in right amounts and correct cooking methods