When leaves make sugar what does the sugar contain?

This question is too vague to produce a good answer. Can you try again with more information about what your situation is?

Different plants produce different kinds of sugars that slightly alter the glycemic index of each food.

If you're referring to stevia-based sweeteners, this plant stores its sugar in a way that the human body can't digest. The sugar molecules are bonded to another chemical. Our bodies can't break that bond so they pass through our systems.