Fig. 3.

Effects of an altered gut microbiome on the gut–brain axis potentially contributing to obesity. High fat feeding can alter host gut microbiota to impair gut–brain axis signaling pathways described within the current review, which can lead to increased food intake and weight gain. Detailed are the currently known mechanisms through which the gut microbiota can negatively impact the gut–brain axis control of energy homeostasis, such as changes in both nutrient sensing and gut peptide response, production of bacterial metabolites, namely SCFAs, and via increased intestinal permeability and metabolic endotoxemia. Numerous other mechanisms likely exist but remain to be further explored. Furthermore, perturbations in early life development or use of antibiotics may lead to an aberrant gut microbiota that can promote similar harmful physiological changes. EEC enteroendocrine cell, LPS lipopolysaccharide, SCFA short-chain fatty acid