Mini Gastric Bypass (One Anastomosis): The Simpler Altern...

Bariatric Surgery · 3 · January 26, 2026

One-anastomosis gastric bypass — also called mini gastric bypass or omega-loop bypass — has quietly become the second most performed bariatric procedure worldwide, surpassing Roux-en-Y bypass in several countries including Turkey, France, and India.

Technical Simplicity: One Connection Instead of Two

Traditional RYGB creates two surgical connections (anastomoses): one between the stomach pouch and the small intestine, and another reconnecting the bypassed intestinal limb downstream. OAGB creates just one — a long stomach pouch connected to the jejunum 200cm from the ligament of Treitz. Fewer connections mean shorter operative time (45-60 minutes vs 90-120 minutes), less potential for complications, and easier surgical revision if needed.

Weight Loss and Metabolic Outcomes

A 2024 randomized controlled trial in Annals of Surgery (the YOMEGA trial 5-year results) compared OAGB to RYGB in 253 patients. Excess weight loss at 5 years: OAGB 85% vs RYGB 79%. Diabetes remission: OAGB 72% vs RYGB 65%. The differences were not statistically significant, meaning both procedures are equally effective — but OAGB showed a trend toward better results with simpler surgery.

The concern: bile reflux. The single-loop anatomy of OAGB allows bile to flow into the stomach pouch. While symptomatic bile reflux occurs in only 3-5% of patients, some surgeons worry about long-term cancer risk from chronic bile exposure. No long-term data (20+ years) exists yet to resolve this question definitively.

Where OAGB Is Performed

OAGB is the most popular bariatric procedure in Turkey, performed at nearly every bariatric center. India's Asian Bariatrics in Ahmedabad is one of the world's highest-volume OAGB centers (1,000+ cases annually). In the US, OAGB remains less common due to lingering FDA caution about bile reflux — most US surgeons default to RYGB. Pricing is typically identical to RYGB: $4,000-$8,000 in India and Turkey.

Cost Comparison

| Country | Cost Range (One-Anastomosis Gastric Bypass)

| United States | $20,000–$35,000

| India | $4,000–$8,000

| Turkey | $4,500–$8,500

| Mexico | $5,000–$9,000

Key Takeaways

- OAGB achieves equivalent or slightly better weight loss than RYGB with simpler surgery

- Operative time is roughly half that of traditional bypass (45-60 vs 90-120 minutes)

- Bile reflux affects 3-5% of patients — long-term cancer risk data is still pending

- OAGB is the dominant bariatric procedure in Turkey and India

Compare real-time pricing using our global cost calculator.