Sugar free sweet is like there would be sweet taste in its made sweet products but it is not a natural one. There are couple of artificial Sweeteners available from the research and in the market that uses for such sweet products, one of them is called Sucralose which compensate for sweet taste without any health affect to patient like diabetes.
Though there are couple of products which compensate as sugar free but they are still affecting in a different mild health process. It may hard to normal digest or metabolism issue etc. It is better to avoid artificial sugar / sweet by pregnant women, children below 12 and other health issue people like phenylketonuria etc.