Which gut bacteria is associated with individuals who are leaner?

The association of gut bacteria with body weight is an important area of research in understanding obesity. Bacteroides is the correct answer, as studies have shown that individuals who are leaner tend to have a higher abundance of Bacteroides in their gut microbiota compared to those who are obese.

Bacteroides species are known to play a role in breaking down complex carbohydrates and contributing to an efficient energy harvest from food. This efficiency may help in maintaining a leaner body weight, as they can promote better metabolic health and a balanced energy homeostasis. Additionally, Bacteroides can influence the immune system and the inflammatory response, which is also relevant to obesity and metabolic syndrome.

The other options pertain to different bacterial groups. Firmicutes are often found in greater concentrations in obese individuals, and there is evidence suggesting an imbalance can lead to increased energy extraction from dietary sources. Lactobacillus is a genus known for its probiotic effects, but the relationship with body weight is more nuanced and not exclusively linked to leanness. Prevotella has been associated with certain dietary patterns and has shown varying associations with obesity and lean body mass across different studies, making its relationship to leanness less definitive than that of Bact