Under the scientific consensus (as presented in the book reviewed here: http://slatestarcodex.com/2017/04/25/book-review-the-hungry-...), I believe the logic is that "chronic exposure" to the sensory experience of sweetness itself does something to the brain involving the body's leptin set-point.

It's definitely something that needs to be proven experimental to apply to these artificial sweeteners as well (and there's already research saying that e.g. artificial sweeteners don't cause the brain to mask tiredness from exercise in the way real sugar does.)