What's the difference between a potato and a candy bar?
About 10 minutes.

(This is obviously an oversimplification. I think there are probably lots of folks who can handle the carbs and oxylates in potatoes just fine, and heaven knows we would be in a dramatically different situation in the US if every candy bar were replaced with a potato. 

But for people who are insulin resistant, it's a useful joke!] 

 This is usually the biggest problem for people going low carb without understanding what they're doing.  They think, it's a healthy complex carb, it's good for me.  Still turns to sugar, still causes insulin to be released.