Aims: Preclinical studies have implicated gut microbiome composition in body weight control, but translatability of finding to humans remains uncertain, due to methodological differences in assessing relationships between diet induced obesity and microbiota. We performed an internal meta-analysis to determine whether inter-individual microbiota differences contribute to individual differences in diet-induced obesity proneness, defined by relative weight gain in response to a high-fat, high-sugar ‘cafeteria’ diet.
Methods: We collated faecal microbiome data from 12 studies using our validated model of diet-induced obesity (total 208 male and 74 female Sprague-Dawley rats fed chow (control) or cafeteria diet, study length from 3.5 to 13 weeks) and determined whether gut microbiota alpha diversity and composition differed between obese-prone and obese-resistant rats, upper and lower tertiles, based on percentage weight gain.
Results: We found consistent effects of cafeteria diet exposure on the gut microbiota, with marked changes in overall composition, and reduced gut microbial richness, Shannon’s diversity index and gut microbial evenness. Furthermore, specific microbial genera previously associated with obesity, such as Bacteroides and Blautia, were enriched by cafeteria diet. Critically, alpha diversity measures and gut microbiota composition did not differ between obese-prone and obese-resistant rats in either diet group.
Conclusions: In rats, microbiota composition is substantially altered by cafeteria diet, but these changes are unrelated to resultant degree of weight gain. Our work suggests that microbiota-targeted interventions are unlikely to reduce diet-induced weight gain or adiposity.