Role of Transcranial Direct Current Stimulation in Appetite and Weight Control

1. To compare weight loss over one month in active tDCS group with sham tDCS group. The investigator will measure weight of every participants at the beginning of the study and one month after the last session of tDCS 2. To compare change in insulin sensitivity over one month in active tDCS group with sham tDCS group. The investigator will measure fasting insulin and glucose level, and calculate homeostatic model assessment-insulin resistance (HOMA-IR) 3. To compare change in cognitive performance as a response to food over one month in active tDCS group with sham tDCS group. The investigator will evaluate performance in a computerized task that measures executive functions under the presence of food (working memory, inhibitory control and a combination of both). The investigator will assess changes in accuracy and speed in the task under active tDCS versus sham tDCS. 4. To compare change in post-prandial glucose excursion and average meal counts per day. The investigator will use continuous glucose monitor to record the frequency and amplitude of glucose excursion.