I consider most 'sugar substitutes' to be pollutants. Splenda is a fine example.
"The FDA has no definition for “natural,” so please bear with us for a biochemistry moment: Splenda is the trade name for "sucralose", a synthetic compound stumbled upon in 1976 by scientists in Britain seeking a new pesticide formulation. It is true that the Splenda molecule is comprised of sucrose (sugar) — except that three of the hydroxyl groups in the molecule have been replaced by three chlorine atoms.
Once it gets to the gut, sucralose goes largely unrecognized in the body as food — that’s why it has no calories. The majority of people absorb about 15% of Splenda in their small intestine.