Noninvasive Neuromodulation of the Prefrontal Cortex in Subjects With Obesity

Participants will receive 10 daily sessions (phase 2) and 3 times a week (phase 3) of tDCS (2mA, 30 min per session). The tDCS montage will target the left dorsolateral prefrontal cortex (DLPFC) (anode: F3 based on the 10:20 system; cathode over the right supraorbital area). For stimulation the investigators will use 5x5cm sponge pads that will be soaked in 0.9% saline during the sessions.

During phase 3, participants will undergo a supervised hypocaloric diet intervention for 2 weeks based on a low-calorie diet (LCD) providing a hypocaloric diet based in 20% reduction from total energy expenditure (TEE). The diet will be individualized on the basis of physical activity levels, age for each participant. This intervention will be be conducted at an inpatient, well-controlled setting to guarantee adherence to the diet. Here the diet intervention will be administered in combination with tDCS. tDCS will be applied every other day (Monday, Wednesday, Friday) over the course of these two weeks.

Subjects in the control group will receive sham stimulation (placebo) (similar procedure and duration as real tDCS, but here electric current flows for 30 s only, to mimic the subjective sensations that occur with active tDCS).