This single-center, randomized, single-blind, sham-controlled pilot study aims to evaluate the adjunctive effect of transcutaneous auricular vagus nerve stimulation (taVNS) in overweight/obese patients who show a poor weight loss response to lifestyle intervention. Participants who achieve no more than 5% weight loss after 12 weeks of lifestyle intervention will be randomized to receive either taVNS plus lifestyle intervention or sham stimulation plus lifestyle intervention for an additional 12 weeks. The primary objective is to compare the percent change in body weight from baseline between the two groups after 12 weeks of intervention. Secondary objectives include evaluation of changes in body composition and fat distribution, autonomic function, liver-related parameters, and glycemic and lipid-related metabolic parameters.