I've always found any of these studies that treat artificial sweeteners as a single group very suspect.
1) The only thing the different types of Artificial Sweeteners have in common is a high sweetness value per volume (2k-4k time more sweet than sugar is common). Other than that they are different chemicals so it seems strange to treat them a single group. Sure a few of them might have issues but it seems silly to say they all have the same single issue. Really a red flag for who funded the study.
2) Due to the very high sweetness levels compared to sugar, even if the artificial sweetener is many times worse than sugar per volume, it is still safer due to only 1/2k being actually being used.
In defense of an otherwise-poor study, it didn't do this. Six of the most common artificial sweeteners were tested on the bacterial assay and their results reported and discussed separately. Another sequence of assays was run on a panel of sports supplements with varying sweeteners. It looks to me like the only reason for grouping these chemicals was practical - they have interchangeable dietary uses, so it's helpful to observe their varying responses on a single test.
It'd be a pretty interesting study, except that the assay's quality and sensitivity seem hugely in doubt.
I think that, assuming the study is high quality, one that looks at all the popular artificial sweeteners together is probably more valuable from a "practical application" perspective, because it allows you to make more of an apples-to-apples comparison among the individual sweeteners.
If all you've got is bunch of isolated studies that only look at one of them at a time, you'll always have some room for doubt about whether a difference in outcome reflects the sweetener being tested, or some difference in the experimental protocol.
I can buy the mechanism of high sweetness/vol mucking with satiety or insulin heuristics. My problem with these studies is that the ones promoted by the media overwhelmingly tend to have "cheated" to obtain positive results -- they claim to have found a link between artificial sweetners and cancer/diabetes/whatever but show the usual signs of severe significance hacking when I skim the paper. My own belief heuristics lead me to the tentative conclusion that effect size is therefore very small.
1) The only thing the different types of Artificial Sweeteners have in common is a high sweetness value per volume (2k-4k time more sweet than sugar is common). Other than that they are different chemicals so it seems strange to treat them a single group. Sure a few of them might have issues but it seems silly to say they all have the same single issue. Really a red flag for who funded the study.
2) Due to the very high sweetness levels compared to sugar, even if the artificial sweetener is many times worse than sugar per volume, it is still safer due to only 1/2k being actually being used.