Its a very interesting question.

One way to tackle it is to see if those consuming things such as diet coke (because they want to avoid sugar and cut weight that way) are successful.

The answer is that reviews of clinical trials reveal that those consuming it instead of sugar really do reduce calorie intake and body weight. For example ...

- See here - (2016 paper) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786736/

- That is similar to an earlier 2014 study ... see here https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4135487/