The intestinal microbiota plays a key role in the pathogenesis of inflammatory bowel disease (IBD), with its composition varying based on geographic location and dietary factors. This study was performed to examine and compare the bacterial composition of the gut microbiota in Mexican and Spanish individuals with IBD and healthy controls, while also considering the nutritional aspects. This study involved 79 individuals with IBD and healthy controls from Mexico and Spain. The fecal microbiota composition was analyzed using 16S rRNA gene sequencing, and the dietary intake and anthropometric measurements were collected. Alpha diversity analysis revealed a lower Chao1 index of the bacterial genera in the IBD groups. Beta diversity analysis showed significant differences in the bacterial composition, suggesting inter-individual variability within the healthy and IBD groups. Additionally, the relative abundance of the bacterial genera varied across the four groups. Faecalibacterium was more abundant in the IBD groups; Prevotella was found exclusively in the Mexican groups, and Akkermansia was found only in the Spanish groups. Akkermansia was positively correlated with meat and protein intake, Prevotella with lean mass, and Bacteroides with calorie intake. These findings highlight the importance of considering geographic and nutritional factors in future research on the gut microbiome’s role in IBD pathogenesis.