Obesity is a serious health problem worldwide and can lead to many diseases such as diabetes, high blood pressure, heart disease, and sleep apnea. When lifestyle changes and medications are not enough, metabolic and bariatric surgery (MBS) is currently the most effective and long-lasting treatment option. This study focuses on one of the newer types of bariatric surgery called Single Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy (SADI-S). This procedure combines two parts: Sleeve gastrectomy, which reduces the size of the stomach so the patient feels full after eating a small amount. Duodeno-ileal bypass, which shortens the path food takes through the small intestine to reduce calorie absorption. Our hospital's surgical team is studying a tailored version of this operation, where the length of the bypassed intestine is adjusted to each patient's anatomy. We believe this personalized approach may improve weight loss results while lowering the risk of vitamin and nutrient deficiencies. The study will include 40 adult patients with obesity who are undergoing SADI-S surgery, either as their first weight loss operation or as a revision surgery after an earlier sleeve gastrectomy. During the operation, surgeons will measure the total length of each patient's small intestine and use a formula to decide how much of it should be bypassed. The duodeno-ileal connection will be made using a stapled technique, which is expected to be safe and efficient. After surgery, patients will be followed regularly at 1, 3, 6, 9, and 12 months, and then once per year. At each visit, the study team will monitor weight loss, body mass index (BMI), resolution of diabetes and other obesity-related conditions, nutritional status (including vitamins and minerals), and any side effects such as diarrhea, reflux, or nutritional problems. The goal of this study is to learn whether this tailored SADI-S technique can provide strong, sustained weight loss and health improvement with fewer long-term complications. The results will help improve surgical planning for future patients by showing whether measuring and customizing the bypass length is safer and more effective than using a fixed length. All data collected will be kept confidential. Patients' participation in the study will not change their regular care or follow-up, and they can withdraw at any time without affecting their treatment.