Yes sweet potatoes do have more natural sugar than regular white potatoes do.
The sweet potatoes contain at least 14 times more sugar than regular white potatoes do.
So if you need to watch your sugar intake then you'll have to cut back on the amount of sweet potatoes you eat.
The sweet potatoes have more sugar than white potatoes because that is one reason that the sweet potatoes are sweet tasting and regular white potatoes are not.
Sweet potatoes although they contain more sugar than white potatoes are still healthy in moderation.
But if you're diabetic and need to watch your sugar intake then white potatoes or regular potatoes would be healthier for you.