Obesity is a major global public health concern, and bariatric surgery is recognized as the most effective treatment for achieving sustained weight loss and improving obesity-related comorbidities. Sleeve gastrectomy (SG) is one of the most commonly performed bariatric procedures; however, long-term outcomes vary considerably among individuals. While some patients maintain satisfactory weight loss, others experience suboptimal weight loss or weight regain several years after surgery. Evidence suggests that long-term weight trajectories after SG may be influenced by metabolic changes, dietary habits, and lifestyle factors, highlighting the need for extended follow-up studies.

This observational cohort study aims to evaluate the long-term outcomes of individuals who underwent sleeve gastrectomy approximately 8 years ago. Anthropometric measurements, biochemical parameters, and nutritional status will be reassessed at an 8-year follow-up visit and compared with data obtained during the preoperative period and at postoperative 6 months. By examining within-subject changes over time, this study seeks to provide insight into the long-term sustainability of weight loss after sleeve gastrectomy and to identify metabolic and nutritional factors associated with long-term outcomes.

Inclusion Criteria:

• Adults aged 18-65 years
• Patients who underwent sleeve gastrectomy approximately 8 years prior to study enrollment
• Patients with available postoperative follow-up data at 6 months, including anthropometric measurements, biochemical parameters, and nutritional status assessments
• Patients willing to participate in long-term follow-up and attend in-person evaluations

Exclusion Criteria:

• Pregnancy or lactation
• Presence of acute illness or active infection at the time of evaluation
• Presence of acute illness, infection, or comorbid conditions that may limit study safety or validity, including malignancy, type 1 diabetes mellitus, renal or hepatic failure, recent stroke or myocardial infarction, nephrolithiasis, drug or alcohol abuse, eating disorders, severe depression or other major psychiatric disorders, inflammatory bowel disease, cardiac arrhythmias or heart failure, respiratory failure, or chronic systemic corticosteroid therapy.
• Professional athletes

The study population includes adults aged 18-65 years who underwent sleeve gastrectomy approximately eight years prior to enrollment and completed standard postoperative follow-up. Participants had available preoperative and 6-month postoperative anthropometric, biochemical, and nutritional data and were re-evaluated at 8 years after surgery to assess long-term outcomes.

Individual participant data will not be shared due to the need to protect patient privacy and confidentiality. T