By “natural ingredients,” people mean ingredients derived from nature.  But every ingredient is derived from nature.  Snake venom is derived from nature.  Arsenic is derived from nature.

It would be an exaggeration to say that you can derive anything from anything, but if you apply enough processing to ordinary proteins and carbohydrates, you can derive all sorts of noxious substances.  To get poisons, you don’t have to start with poisons.

The term “natural ingredients” would be meaningful and helpful only if it were used to mean ingredients which beings of our nature can consume safely.  If we don’t use it that way (and we don’t), then we might as well get rid of it.

So in case the title of this post confused you, I’m completely on board with natural ingredients.  I oppose only “natural ingredients.”