Described herein is a system which uses a gene therapy particle that includes at least one gene, cDNA, fragment or analogue of at least one neurotropin that binds to the trkB receptor or the trkB receptor itself. The gene therapy particle is capable of being delivered to a subject in need thereof for therapy of a metabolic disorder. In a particular aspect, this invention is directed to an inventive method that demonstrates a remarkable efficacy on lowering body weight.