That may be true, and all we can say is that it's an exciting, but immature field. I'm no expert on microflora, and I won't critique it as such. However, I wouldn't take the main conclusion of the paper to be about the microflora anyway. That's the mechanistic part of the study, and perhaps the less relevant part (although I understand why they made the paper mostly about that). The more interesting finding here is the effect of artificial sweeteners on blood glucose. Feeding the mice glucose led to lower glucose levels than saccharin, sucralose, or aspartame. That's something right there, because insulin tolerance is one of the major drivers of diabetes and cardiovascular disease, or the shit that kills pretty much everybody who doesn't die of cancer. Some researchers have speculated that insulin metabolism may be a driver of aging and cancer, as well. It's a big deal, and reducing insulin tolerance could save mucho dinero for our health system going forward. The total costs related to cardiovascular disease is projected to be pushing a trillion dollars by mid-century. Not exactly chump change. These insulin tolerance data, whether they turn out to have anything to do with gut bacteria, should be repeated in humans. The data on that topic, so far as I can tell, are surprisingly sparse, considering how much these (IMO) poisons are added to actual food. I've been trying to get my mom to stop drinking Diet Coke for years. It's funnt that in health class in high school they tell you not to do drugs, and that one of the dangerous things about street drugs is that you never know what's in them. Then your teacher goes on conference hour and sucks down a diet soda and a bag of Cheetos, without giving any thought to wtf is in that shit. Hopefully, more attention can be paid to food additives in the future, and we can start to build a more logical food system.A lot of it is crap and the field as a whole is still quite immature. There's not many benchmark references for how the biome changes across different timescales with the many many possible diets a human may have on a given week / month. Seeing a change in proportion of bacterial populations in the stools is a far cry from even a smoking gun in a system as complex as the human gut.