Wow, thank you, Dan! You really seem to have put much work into this.
The results are quite interesting - but as I understood it they refered to solid foods. Whether gum “replaces” liquid foods is a different question, as the latter involves no chewing which could be replaced by anything else.
The sweeteners may also play a role - maybe some are better than others (for example xylitol versus aspartame).
Taste activates the vagus nerve, which in turn activates secretion of digestive juices, which may increase appetite.
Maybe there is a high difference between individuals. Appetite is such a complex phenomenon that it is hard to do the right things with regard to its control.
Nevertheless the - theoretically - best strategy might be training your mind not to crave sweet things in the first place - regardless of whether you are hungry or not. But this is far more difficult than just chewing or drinking something. Advice is appreciated here, too…