Adding to the anecdotes:<p>Around summer 2014, I began to focus very heavily on "bulking" for strength training. This was about a year after I'd developed very obvious symptoms of lactose intolerance and had had to cut uncultured dairy out of my diet. My meals were not diverse: fruit and Greek yogurt in the morning; chicken cooked in Indian sauces, roasted potatoes, and some green (usually broccoli or spinach) for lunch and dinner, along with protein shakes and a pre-workout carb load (such as PB+J). Drinks were water, orange juice, and kefir.<p>That winter, my health collapsed. I started developing skin abscesses, and the antibiotics I received for a particularly bad episode caused me to develop a C diff infection. I had to severely limit my food intake, as too much or certain kinds would cause me to develop cramps, listlessness, and diarrhea,
and lost about 40 pounds in 3 months. My body could not hold onto food long enough to process it correctly and I developed symptoms of incomplete digestion, and especially of fat indigestion (symptoms improved with anti-diarrheals).<p>The next 3 years were a long battle to try to get back to normal. Store-bought probiotics didn't help; digestive enzymes did. Things didn't improve noticeably until after I began eating homemade sauerkraut, and especially after I began taking enzymes on an empty stomach (I was told that this might help to break down some structure that might harbor unhelpful bacteria).<p>Eventually, I was able to return to most foods without issue, until last year, when a prediabetes scare prompted to try a ketogenic diet (this also seemed to solve a lingering issue, of multiple daily and urgent movements).<p>All this to say... I don't really know what's going on. I've found some things that seem to work, but I could only guess at why, based on the timing of my downturns and upturns and of my interventions.<p>I've spent literal days over this period trying to understand why my body is acting and reacting the way that it does, and following the (often slapdash) advice of people who target the microbiome as the source of ill or good health has sadly seemed to be the most efficacious route. However, I'm still not able to achieve the level of well-being I'd like to, and I attribute that largely to the dearth of hard facts available relating to diet and the human microbiome. Over the course of this journey, I've seen more and more professionals begin to take the issue seriously, but not nearly the level or quality of research we'd hope to see with such a fundamental topic. Here's to seeing that corrected before I have to punch whatever card this adulthood of gut trouble has been leading to.