The present invention discloses adeno-associated viral vectors useful in gene therapy methods for the treatment of obesity, insulin resistance, type 2 diabetes, liver cirrhosis and non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH). The invention also relates to polynucleotides, plasmids, vectors and methods for the production of such adeno-associated viral vectors. The invention also relates to pharmaceutical compositions comprising said vectors.