Benign hepatosteatosis, affected by lipid uptake, de novo lipogenesis and fatty acid (FA) oxidation, progresses to non-alcoholic steatohepatitis (NASH) on stress and inflammation. A key macronutrient proposed to increase hepatosteatosis and NASH risk is fructose, whose excessive intake causes intestinal barrier deterioration and endotoxemia. However, how fructose triggers these alterations and their role in hepatosteatosis and NASH pathogenesis remain unknown. By preventing fructose and endoplasmic reticulum stressdependent barrier deterioration and subsequent endotoxemia using a chemical chaperon, activation of mucosal-regenerative gp130 signaling, administration of the YAP-induced matricellular protein CCN1 or expression of anti-microbial Reg3β peptide, we show that microbiota-derived Toll-like receptor (TLR) agonists promote hepatosteatosis without affecting fructose-1 phosphate (F1P) and cytosolic acetyl-CoA. TLR engagement triggers TNF production by liver macrophages to induce lipogenic enzymes that convert F1P and acetyl-CoA to FA in mouse and human hepatocytes.