A method system for modulating the energy expenditure and/or the expressed brain-derived neurotrophic factor (BDNF) in the brain of an individual is performed by a system that includes a control device that generates a stimulation pattern from a predetermined set of stimulation parameters, and that converts the stimulation pattern into a stimulation signal. A stimulation signal delivery mechanism, configured for implantation into a selected part of the brain, receives the stimulation signal from the control device and delivers the signal to the selected part of the brain. The stimulation signal may be an electrical signal delivered by a brain-implantable electrode, or a chemical signal in the form of a drug dosage regimen delivered by an implantable micropump under the control of the control device. Modulation of the energy expenditure and/or BDNF is achieved by the stimulation of the hypothalamus, either directly or indirectly, by the stimulation signal.