Sounds like crazy talk to me.
Beverages containing low energy sweeteners do not differ from water in their effects on appetite, energy intake and food choices in healthy, non-obese French
The Coca-Cola Company (Atlanta, USA) was the sponsor of the study and the International Sweeteners Association (Brussels, Belgium) supported the presentation of results.
āThe present study, a two-arm randomized clinical trial (RCT)ā
Not the most exhaustive trialā¦
Iām not healthy. I am obese. Iām not French.
So I guess the results donāt apply to me. 
And, based on the sponsors, I suspect no bias in the results. 
OTOH, I have found (near) calorie-free sparkling waters help āfill me upā betterā¦
While not all RCT trials are equal, generally, better than population studies. Generally, RCT is the gold standard.
Always sceptical of studies sponsored by someone who has a multi-billion dollar interest in the outcome. However, within the bounds of the study, this one looks fairly solid.
If you wanted to be truly cynical - or perhaps paranoid, you might ask whether the study was contrived. Why select only 160ish people out of the 2k+ that applied. Did they run multiple studies and ignore the ones which did not produce the results they wanted? Why 660ml per day? Why 5 weeks?
Reasonable explanations given for all, but what if the cause of weight gain observed in population studies was that gut microbiota changed after 5 weeks, and TEI skyrocketed after that? Or the process was a lot faster at 3 servings a day (990ml) rather than 2? (660ml)
I tend to be sceptical, but not paranoid. Iām happy to accept that low levels of consumption, donāt cause acute issues. Iām also happy that for an RCT N=1, I have suffered no deleterious effects. Also, population study of N=however many people I know that drink it, any effects donāt appear to be acute.
In context though, diet soft drinks has helped me stick to low carb, and the benefits of low carb appear to outweigh any deleterious effects of LCS, so Iām happy to continue with it, unless thereās reasonable evidence that there are long term effects I hadnāt considered. If such evidence was produced, Iād reconsider.
In related news, artificial sweeteners are observed to be correlated with obesity and metS. So, I dunno about this study.
Of course its correlated. If you are already overweight, youāre more likely to look for ways to cut calories.
But do fat people drink diet drinks, or do diet drinks make people fat? Correlation wonāt tell you.
Most studies are dumb.
N=1: when I cut my Diet Coke habit, I have the best success with the program. When I do the program with ad libitum Diet Coke, I fail within three months.
Conclusion: I dunno if they are obesogenic, but I question their utility in the redesign of a healthy lifestyle that doesnāt include daily sweetness.
For what itās worth (not much) - Iāve lost 90 pounds while drinking diet soda. Iāve also tested - I fasted, waited until my blood sugar was stable, drank diet soda and checked my blood sugar. No change. Now, my reasoning is that if I was getting an insulin response, it should dropped my blood sugar.
This is also in periods where my blood sugar isnāt as low as it could be - where taking something like Glipizide will cause my blood sugar to drop. So in theory, if diet soda were causing an insulin response in me, I should be able to see it.
But the key phrases there are āin meā and āin theoryā.
Iāve also gone long stretches where I kept my diet stable and didnāt do diet soda. No difference in anything I measure.
That said, thereās more to things than insulin response - I donāt really have a sweet tooth. The diet soda is a convenient caffeine delivery mechanism more than anything. I can easily see if you did it might cause you to eat poorly.
And, again, this both personal to me and could be wrong.
Iām going to be testing out fasting on just tea and coffee and see if thereās a long term improvement in my blood sugars.
(I do a lot of N=1 experiments, mostly to keep me from getting bored)
We already know from experience on these forums that everyone reacts differently to each diet sweetener, and that some people are perfectly fine, while others get insulin spikes. It stands to reason that metabolically healthy people consuming a modest quantity of such things might very well have no problem.
On the other hand, the rest of us should probably proceed with a bit of caution. In other words, take this study with a grain of saltāboth literally and figuratively, lol! 