BDNF and obesity due to melanocortin 4 receptor deficiency: Both SCFAs can be absorbed by the host and contribute to higher caloric intake from food, leading to weight gain and obesity [46], while also strengthening the intestinal barrier and contributing to proper colonocyte function, reducing intestinal permeability and preventing lipopolysaccharide (LPS) from entering the bloodstream, thereby preventing systemic inflammatory processes and possibly promoting an increase in brain-derived neurotrophic factor (BDNF), a crucial factor involved in brain plasticity, mood regulation, and cognitive function [47].