The importance of diet shaping the gut microbiota is well known and may help with improving the overall health of an individual. Many other factors also have an influence, such as genetics, age, exercise, antibiotic therapy, or tobacco use. The purpose of this review is to summarize how three distinct dietary types (plant-based diet, Mediterranean diet, and Western diet) affect the composition of gut microbiota and the development of non-communicable diseases (NCDs). PubMed, Web of Science and Scopus databases were used for searching papers with an emphasis on keywords ‘‘dietary pattern’’, ‘‘gut microbiota’’ and ‘‘dysbiosis’’. Plant-based diet and Mediterranean diet promote the production of beneficial bacterial products, and more microbial diversity and therefore are generally considered healthy dietary types. On the other hand, the Western diet is a typical example of an unhealthy approach to nutrition which leads to an overgrowth of pathogenic bacteria. Moreover, understanding the impact of diet on the modulation of gut microbiota may give rise to new therapeutical strategies.