Gut microbes need fiber to function efficiently. A new study published in the journal Cell found that certain types of gut bacteria rely heavily on fiber in their daily diet. When their meals are lacking in fiber, these microbes begin eating away at the mucus layer surrounding your gut. As creepy as that sounds, it also has some serious side-effects. When gut microbes feast on your gut walls it causes inflammation and infections, which can do harm to your body overall. While future research will further determine how these microbes function, for now we can keep eating a variety of natural fiber to keep the gut happy.