Fasting seems to benefit the gut microbiome, though more research is needed.
According to one small 2019 study of 16 people, fasting was linked to lower levels of a bacteria that promotes colorectal cancer.
Research in animals also shows benefits of fasting. A 2018 studyTrusted Source in fruit flies found that intermittent fasting appeared to improve gut health and increase lifespan. Another 2019 studyTrusted Source in mice indicated that fasting promoted the growth of beneficial gut bacteria and reduced inflammation in the intestines.