Host-mediated Remodeling of the Gut Microbiota in Energy Homeostasis and Environmental Resilience

The gut microbiome dynamically regulates mammalian energy homeostasis by remodeling its composition to optimize nutrient extraction and persistence, often exacerbating obesity under energy-rich diets through disruption of host intake–expenditure balance. For instance, phylum-level dynamics like Firmicutes dominance enhance energy harvest, while species such as Akkermansia muciniphila bolster barrier integrity, appetite control, and thermogenesis. Building on this, bidirectional host–microbiome interactions deploy feedback mechanisms to curb excesses and boost expenditure, guided by the hologenome framework where host genetics foster microbial resilience. This remodeling model portrays symbiosis as a flexible equilibrium, sustained by diversity, competition, and cooperation, enabling adaptation to stressors but susceptible to dysbiosis. Cold exposure exemplifies host-led remodeling, sculpting a specialized “cold microbiota” through neuroendocrine, metabolic, mucosal, and behavioral pathways to amplify thermogenesis and energy efficiency, illustrating co-evolved hologenomic adaptations for environmental challenges and potential interventions in metabolic disorders. Ultimately, this review explores how the host dynamically regulates energy homeostasis by managing microbiome dynamics.