Are baked potatoes a good diet food?

They would seem to be. They are low in calories if you are careful of what you put on them and they are filling. I have even seen Web entries about potato diets.

According to low carb promoters, baked potatoes are the worst possible diet food because they have a high glycemic index, meaning that they are readily digested and quickly produce a lot of blood sugar. It is claimed that it is actually better to fry the potatoes in order to slow down digestion.

So which point of view is correct?