Bacteroidetes are the most prominent gut microbes in much of the world. They are thought to help protect against obesity because they do not digest fat well.

The Bacteroidetes Phylum marker refers to a group of bacteria commonly found in the human gut, playing a crucial role in the digestive process. This phylum includes various species that are essential for breaking down complex molecules like carbohydrates and fibers, helping in the absorption of nutrients and the production of short-chain fatty acids which are vital for gut health. The presence and balance of Bacteroidetes can be an indicator of gut flora health; for instance, a healthy balance between Bacteroidetes and another major gut bacteria group, Firmicutes, is often associated with good digestive health.