Concordant with those observations, obesity and NAFLD associates with metabolic endotoxemia, i.e., increased blood levels of lipopolysaccharide (LPS), a component of the wall of Gram-negative bacteria that binds to specific receptors, toll like receptor-4 (TLR-4), and can promote hepatic and systemic inflammation [47,49,50]. Here, TLR4 is linked to obesity due to melanocortin 4 receptor deficiency.