Greek yogurt contains probiotics, which are "good bacteria" that may help promote healthy gut bacteria. Having healthy bacteria helps with digestion and immune function and increases the absorption of certain nutrients. However, it is unclear if probiotic-containing foods influence your gut bacteria. Different brands of Greek yogurts contain different strains and different levels of active probiotics depending on how the yogurt is processed. Some brands add additional probiotics to their products including for potential added health benefits. Take a look at the product label and look for brands that say "live active cultures". The influence of dietary intake on the gut microbiome is an exciting area of research in nutritional science. While more research needs to be done to fully understand the effects of dietary intervention on the gut, diets high in fiber are associated with improved gut health. Research on probiotic-rich foods is less clear, though intake of probiotic-rich foods, including yogurt, may help to support optimal microbial diversity in the gut.