Dear Gavinray What you said is very intuitive however not entirely true. Let me explain: Bacteria are happy no matter what as they (as community of different b

Dear Gavinray What you said is very intuitive however not entirely true. Let me explain: Bacteria are happy no matter what as they (as community of different bacteria) can adjust to content of the human gut; i.e. when we feed simple sugars (in contrast to fibre that is a polymer made of many sugars) some microorganisms will be more than happy to go on simple sugar-diet that requires less energy to consume it. However it can disregulate metabolic network of microbiome that has been co evolving with fibre based diet rather than simple sugars. Early humans consumed much more plant based fibre and therefore we hardwired our human metabolism and twicked immune response to co exist with microbiome that consumes fibre. Let me give you an example: when microbiome gets fibre from our diet it returns us side products of fibre metabolism including short chain fatty acids (scfa). They(scfa) stimulate many receptors in our body and keep us healthy. So in summary: microbiome will adjust its metabolism to what is available and will be always happy given there is any food. Microbes can even consume our own mucosa when we starve or when we die. It is more about keeping the community of microbes at homeostasis (in contrast to dysbiosis). Keeping them on diet that we used to feed them for hundreds of thousands years of our co evolution even preceding primates appearance. Our bodies depend on side products of microbial metabolism of what we used to feed them and definitely not of what western like diet feeds them nowodays. We live in the world of disregulated microbial metabolism. It disregulates us, our own metabolism, our brains, our immune responses, almost all tissues. We cause dysbiosis of the global ecosystems on the planet. This is reflected in the dysbiosis of our own gut. We are degenerating our microbial shield and degenerate our and other species.