To test the hypothesis that subchronic exposure to low doses of AhR ligands could be a cofactor in the development of fibrosis in obesity related-NAFLD, male mice were fed either a LFD or a HFD for 14 weeks and were injected weekly with either 5 μg/kg TCDD (LF-tcdd and HF-tcdd, respectively) or the vehicle (LF-ctrl and HF-ctrl, respectively) for the last 6 weeks of the diet intervention. This evidence concerns the gene AHR and obesity due to melanocortin 4 receptor deficiency.