Reddit reviews Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues

Try "The Skinny Gut Diet". I've just finished listening to Missing Microbes and so far, apart from a little dumbing-down and reference to the questionable "leaky gut", Skinny Gut Diet seems to be a good guide to getting some practical value out of the idea that gut bacteria have a major effect on obesity.

If you'd rather avoid something structured like a diet book and just dive straight into a more scientific exploration, feel free to skip straight to Missing Microbes, although then you'll have to translate it into a diet yourself.