Due to the increased availability of high-throughput DNA-sequencing technologies and quantitative PCR, investigators have flooded the scientific literature with reports describing the composition of different gastrointestinal microbiotas. With the use of gnotobiotic isolators housing axenic animals, i.e. germ- or microbiota-free animals, investigators have also undertaken more hypothesis-driven research addressing putative roles for the microbiota in host health. Possibly inspired by the patent spread and pathogenesis of obesity and metabolic syndrome, in combination with the observation that a commonly used strain of germ-free laboratory mice are more resistant to obesity than their conventional counterpartsÂ a major focus of much of this work has considered the relationship between the microbiota of the host and the susceptibility of the host to obesity. Additionally, compared to many existing and theoretic therapeutics to counter the obesity pandemic, the microbiota is potentially a more practical target. I attempt to very briefly summarize, for nonprofessionals of microbiome study, the composition of the microbiota as it relates to obesity in humans. This is intended to provide the reader with sources for finding further information, including primary research that has contributed to our knowledge and more comprehensive reviews on the relevant topics mentioned.