Most people try to avoid talking about poop, at least in polite company. But, there's no denying it's a universal experience — one that could use a little more appreciation. Which is why Rob Knight, PhD, professor at the University of Colorado Boulder and founder of the American Gut Project, took to Reddit yesterday to answer our most pressing questions about poo and the bacteria in our guts that make it all happen. Here are the most interesting facts we learned about our bowel movements. 1. We may one day be able to use our gut bacteria as a source of energy. "It's a really good idea," says Dr. Knight. Apparently several groups have been working on making this happen; just a few weeks ago it, a study was published in Nature Communications showing that researchers used gut bacteria to create a renewable type of propane. But, Dr. Knight cautions, scaling up this kind of system outside of the lab will definitely be a challenge. 2. Probiotics might be worth it. Although the effectiveness of probiotics is still largely up for debate, Dr. Knight points out that there is some peer-reviewed research out there suggesting that the probiotic drink Yakult specifically could be beneficial for keeping our guts working regularly. But, Dr. Knight notes, most of these studies have only been done with infants — probably not the most generalizable group of participants.3. Fecal transplants are a viable option to treat some serious diseases. Fecal microbiota transplants — exactly what they sound like — are surprisingly effective in combatting illnesses such as potentially-deadly C. diff infection. But, Dr. Knight says the FDA's regulations make it difficult to research fecal transplants in the U.S. This, combined with doctors' reluctance to perform the procedure, has led to increased focus on synthetic poop and DIY fecal transplants. Yep. 4. Being nice to our gut bacteria is pretty important — and easy. By and large, Dr. Knight's advice for keeping our microbiota satisfied is what you'd expect: Although we're all individuals and our bodies react to different things in different ways, he says, eating plenty of leafy greens, brightly colored veggies, and fermented foods is usually a good idea. But, try to stay away from fried and highly processed foods. Artificial sweeteners have also been recently shown to mess up that system, so put that Diet Coke on the naughty list. 5. "Biological dark matter" is a real thing. In astronomy, dark matter is what we call the mysterious something that composes approximately 27% of the universe that isn't energy or normal matter. Here, it's a similar concept. Biological dark matter, says Dr. Knight, has two meanings: First, it can refer to the vast majority of environmental microbes that we've never been able to see under a microscope or culture ourselves. Or, it can mean the many isolated environmental genes that we haven't been able to trace back to a full genome. In either case, there's a lot left to discover. If you're still curious about your microbial gut residents or your poop in any shade of brown, check out Dr. Knight's massive open online course. But, if your poo's suddenly going green, that's another story. Like what you see? How about some more R29 goodness, right here? Why Christian Bloggers Think Yoga Pants Are Sinful 7 Sleep Gadgets That Actually Work Why Does This Ring Turn My Finger Green?