>An important missed angle is the effect of artificial sweeteners on gut microbiome.
Everything affects the gut microbiome. Every single type of food you eat alters it. Taking a walk alters it. Taking a flight alters it.
The whole "but it changes the microbiome" thing needs to be qualified by whether that change is meaningfully relevant in some direction, and evidence thus far, for most sweeteners, is unconvincing. 10.1016/j.cell.2022.07.016 is the only mildly legitimate research on this (a seemingly well executed RCT), but even it shows a rapidly fading effect, and no effect for aspartame given it's the subject of this submission.
But researchers who want a bit of attention (and a remarkable amount of research is plied not for useful results, but knowing that certain topics are easy mass media coverage) know it's gold to write a paper saying a sweetener changed the microbiome, because it plays into a fear people have (people are always susceptible to the "too good to be true" aha moment). Or worse still the garbage observational studies that conflate that people with metabolic issues are more likely to use sweeteners, so flip cause and effect and claim that sweeteners cause metabolic issues.
>What's the harm in sticking to a balanced whole diet of ingredients that were available to our ancestors 200years or more ago.
If people ate calorie-restricted, balanced diets, and limited simple carbs and sugars, most food problems fade away (presuming they aren't eating overtly poisonous things, which many of our ancestors did). But that isn't reality. In reality sugar is one of the greatest health crises of our times, and finding some mechanism of reducing that problem is beneficial. Better still people should tame the sweet tooth, but we live in reality.
And FWIW, you can do the reductionist thing that wellness grifters do with most any food. Loads of "balanced whole diets" are full of crazy, scary constituents, many of which are known carcinogens. Spices and herbs are full of deleterious ingredients. And so on.