[Laforet]

This paper you linked does not even involve aspartame. The only sweetener they experimented with is saccharin. You can check out the main figures from the link below:

https://www.researchgate.net/publication/265791239_Artificia...

I would be very reluctant to read too deep into this given saccharin is known to behave very differently in animal models - for a long time it was thought to cause bladder cancer, but follow up studies proved that it’s an idiosyncratic reaction only found in female lab rats and no other gender/species combination. Not to mention the dose used was unrealistic to begin with.

It’s entirely plausible that sugar analogs like sucralose and non-calorific sugar alcohols such as erythritol and maltitol can cause long term changes in the gut biome but high quality evidence is still lacking.