The gastric sleeve and the gastric bypass are the two most commonly performed weight loss operations. Both are done by keyhole surgery and both lead to substantial weight loss, but they work differently and suit different patients. In this guide New City Clinic explains the differences your surgeon weighs up when recommending one or the other.
How do the two operations differ?
In a gastric sleeve, around 75–80 per cent of the stomach is removed, leaving a narrow tube; the route food takes is unchanged. In a gastric bypass, a small stomach pouch is created and connected directly to the small intestine, so food bypasses most of the stomach and the first part of the intestine. The sleeve is technically simpler and shorter; the bypass adds a change in how food is absorbed and in gut hormones.
Who is each one suited to?
A sleeve is often chosen for patients without significant reflux who want a straightforward operation. A bypass is frequently preferred for people with marked acid reflux, because a sleeve can make reflux worse, and for those with type 2 diabetes that is difficult to control. Eating habits matter too. The decision is made by a general surgeon after endoscopy, blood tests and assessment by the wider team, not from BMI alone.
Life after surgery
Both operations require lifelong vitamin and mineral supplements and regular blood tests; after a bypass the need is greater because absorption changes. Dumping syndrome, an unpleasant reaction to sugary foods, is more typical after a bypass. A sleeve cannot be reversed, though it can be converted to a bypass later if needed. Lasting results depend on diet, activity and follow-up, whichever operation you have.
Weight loss surgery: cost in Turkey and what is included
The price depends on the technique, the extent of the procedure, the hospital, the length of stay and any procedures planned together, which is why a single figure quoted without an examination or photo assessment is misleading. After a physician has reviewed your case, New City Clinic sends you an itemised written quote. It lists hospital, surgeon and anaesthesia fees, pre-operative tests, medication, any compression garment or support bra, accommodation, airport–hotel–hospital transfers and interpreting separately; flights are not included unless stated. When comparing clinics in Istanbul, look beyond the price: check that the hospital is licensed by the Ministry of Health, what the surgeon specialises in, and how follow-up is handled once you are back home.
Weight loss surgery with New City Clinic
New City Clinic is an authorised health tourism intermediary registered with the Turkish Ministry of Health and HealthTürkiye. When you contact New City Clinic about weight loss surgery, a physician first reviews your photos and medical information, and you then receive a written treatment plan with an itemised quote. Once you arrive in Istanbul, the New City Clinic team organises your airport welcome, accommodation, hospital appointments and interpreting. Your procedure is performed by a specialist physician at a Ministry of Health approved partner hospital, and follow-up continues after you return home.
Recovery timeline
2–3 nights in hospital
Leak tests are carried out and you start walking and sipping fluids on the first day.
First 2 weeks
A liquid diet; most patients fly home on day 5–7 after their check-up.
Weeks 2–6
Purées, then soft foods, following the dietitian’s plan. Desk work is usually possible within 1–2 weeks.
Months 12–18
Most weight loss takes place; supplements and blood tests continue.
Accommodation and transfers
On request, New City Clinic organises your airport–hotel–hospital transfers and your stay at partner hotels close to the hospital. The same can be arranged for a companion; details are set out in writing in your quote.
Aftercare
Medication and check-ups
Take the medication your physician prescribes as directed and attend your planned check-ups.
Smoking and alcohol
Both slow healing; avoid them before and after the procedure for the period your physician advises.
Movement and rest
Short walks support circulation; wait for your physician’s approval before strenuous exercise or heavy lifting.
When to get in touch
Contact your New City Clinic coordinator straight away in case of high fever, increasing pain, redness or anything unexpected.
Frequently asked questions
Which operation gives more weight loss?
Average results are broadly similar in the first years, with a bypass often slightly ahead. Individual outcomes vary and depend heavily on following the diet and follow-up plan.
I have reflux. Can I still have a sleeve?
Significant reflux or a hiatus hernia usually tips the choice towards a bypass. An endoscopy before surgery shows your surgeon what is appropriate.
Can a sleeve be changed to a bypass later?
Yes. Conversion is an established revision operation, considered for severe reflux or insufficient weight loss after careful assessment.
Deciding on weight loss surgery is a confident step when it is taken with the right information and the right team. You can book a free consultation with the New City Clinic team for your questions.
This article is for general information; consult your physician for diagnosis and treatment.
