There is a constant refresh of information on the benefits of balanced microflora in the gut. Scientific studies arrive from multiple fronts on a weekly or biweekly basis. The glory in the details usually defaults to the "probiotics" usually sourced from certain types of fermented foods. Indeed, most people now deliberately include live culture yogurts as part of their regular intake, as a result of what is now a common general knowledge about increasing the levels and varieties of our gut biota. But the "prebiotics" that are comprised of undigestible dietary fiber are the heavy lifters inside of us. These dietary fibers, which are passed as bulk from our systems, are also fermented deep in our guts by our good guy microflora--which require these dietary fibers, otherwise known as prebiotics, in order to multiply and thrive.
Imbalances, or what are conservatively defined as differences in microflora, between the afflicted and unafflicted, are implicated in serious and disabling health issues. The most impactful of these issues are autism, and obesity. It is easy to imagine that the skinny folks who eat what most consider to be a terrible diet have a wonderful internal factory of a microbiome that is cleaning up after their careless ways. While on the other hand, the obese person taking up space next to them on the subway may be doing everything possible to be healthy and minding their calories, and yet the flora in their guts is undermining their every healthy mouthful and calorie burned.
As to the folks of all sizes and shapes, who comprise the majority in western societies that enjoy sweets in excess, studies have revealed there are sugar-loving bacteria which send signals to our brains that make us crave sugar. The way to disrupt the sugar lovers in our guts, is to use our brains and resist their urges. So easy to imagine how literally, these wily devils on our shoulders telling us to go ahead, have that cake and eat it, are actually cunning little symbiotic bacteria controlling our brains!
Some may prefer an alternative to ignoring little bacteria which are managing our love of pastries. Like eating live active culture yogurt, fecal transplants are a thing now, and studies have followed the effects of implanting the fecal matter from thin people with a good range of microflora into obese people who have a narrower range of microflora including types that are very detrimental to wellbeing. Some who are satisfied with this alternative practice just stop there, and there are people who regularly implant the fecal matter of healthy thin people into their guts, without realizing they can probably achieve the same effects by sourcing a wide range of microbiota and keeping them flourishing with a prebiotic type of dietary fiber.
Medical fecal transplants for people with inflammatory bowel diseases are remarkable in that they require a consistent regimen of implantations in order to replenish the gut microflora of sufferers. So how to get to a stasis, or steady state, where the gut factory takes over and does what it does best, that is, provide a home to symbiotic bacteria which perform an uncountable number of good deeds? It seems so hard to comprehend the power of our symbiotic inhabitants, primarily because there are so many different types of bacteria, and the scientific understanding is only in the early stages. Circa 2016 studies which involve the gut biome will usually open with a statement or abstract which contains a common and acknowledged recognition of the role of the gut microbiome in host metabolic health and disease.
Earlier studies were more hesitant to open up with boldly worded declarations about the role of the gut microbiome for human health. We have come a long way from hesitating to understand how our health is impacted by unseen billions of organisms which reside within our digestive system, and which are directly responsible for our health and wellbeing.