Indeed. A important talk we all need to have is what makes a healthy diet. I mean since the industrial revolution we have been so busy in our lives, and all kind of processes and yummy junk food items are so readily available. While I completely understand that it is difficult to survive without those. Like if not that processed table sugar, what am I supposed to put in my milk coffee that makes it equally tasty? Apart from being yucky I dont even know what all effects would artificial sweetners such as sucralose have on the gut bacteria! And no, I dont think even my counterpart in any of the possible parallel universes would be using stavia!
Nevertheless, we can be conscious and mindful about the usage. And, at least make our diets better in other aspects. For instance, increase fiber intake.
But that being said one has to be careful in thinking of diet as a magic bullet as well. I mean it makes a lot of difference. But there are other factors - mental stress, sleep, environmental pollutants etc that we hardly talk about. They also affect the gut microbes.
Then guy microbes can be shaped by our genetics. Even the presence of tumor in the body changes the abundance of different bacteria. It's a two way talk between the human cells and bacterial cells. But yes, we can't change our genetics or disease once it's developed, but we can sure try our best with diet and having a good mental health.