This study aimed to investigate the consequence of Ramadan fasting on gut bacterium (Bacteroides and Firmicutes), serum concentration for butyrate, and lipid profile.Thirty healthy subjects were enlisted and investigated two times (before and at the end of Ramadan). Fasting blood samples were obtained for measuring fasting blood sugar (FBS) and lipid profile and serum butyrate concentration. Anthropometrics variables were measured before and after Ramadan for all 30 subjects. Quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis, targeting the genome of Bacteroides and Firmicutes was performed to determine its presence in the stool samples. Food intake was assessed by a 3-day food record before and after Ramadan. Statistical analysis was performed by SPSS ver.13 and Minitab ver.17. P 0.05).It can be stated that the promotion of Bacteroides and Firmicutes in the gut might play a crucial role in health promotion. However, more research is needed to achieve a definite conclusion.