Bacteroides
Bacteroides is a major genus within the Bacteroidetes phylum and one of the most abundant groups in many adult guts. Its members are versatile carbohydrate fermenters that help break down a wide range of dietary fibers and sugars.
Because it is so common and flexible, Bacteroides is a workhorse of digestion and nutrient extraction, and its share often reflects overall dietary patterns. It features heavily in discussions of how diet, especially protein- and fat-rich versus fiber-rich eating, shapes the gut.
A higher Bacteroides share means this group forms a larger part of your sample and is often associated with certain Western or protein- and fat-rich dietary patterns. Since the value is relative and this genus is broad, a higher share is descriptive rather than inherently good or bad, and not a diagnosis.
A lower share means this group occupies a smaller portion of your sample relative to others, which is best read alongside your diet and the rest of your community.
There is no established ideal Bacteroides percentage, as the genus is broad and diet-sensitive. Given how young this science is and that the value is relative, focus on diversity and dietary variety and interpret with a clinician.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.