- Small stomach pouch plus a bypass of part of the small intestine.
- Typical loss: about 30-40% of total body weight.
- First choice with type 2 diabetes and reflux (Vitalys).
- Drawbacks: dumping, internal hernia, lifelong supplements.
- Covered by Dutch basic insurance; you pay the €385 deductible.
What is a gastric bypass?
In a Roux-en-Y gastric bypass the surgeon staples off a small pouch at the top of the stomach and connects it to the small intestine, further down than normal. The rest of the stomach stays in place but no longer receives food. The operation is done laparoscopically and takes about 90 to 120 minutes.
Because food reaches the part of the intestine that releases satiety hormones earlier, the body starts steering towards a lower weight. WeightWorks describes this as shifting the set point. In people with type 2 diabetes, blood sugar often improves before much weight has been lost.
What about alcohol after a gastric bypass?
After a bypass, alcohol reaches the intestine much faster and is absorbed straight away. Blood alcohol peaks faster and higher and stays in the body longer, according to the Belgian Druglijn. A minority develops alcohol problems after surgery. Surgeons at Ghent University Hospital say more and more doctors advise that alcohol is not a good idea after this operation. Never drink and drive.
What are the drawbacks of a gastric bypass?
The main structural drawback is reduced absorption of nutrients. Without supplements, deficiencies of iron, vitamin B12 and folic acid develop, and to a lesser extent zinc, selenium and vitamins A, E and K. You therefore take a WLS multivitamin and at least 1,500 mg of calcium with vitamin D a day, for life.
Dumping can occur when sugar or fat reaches the small intestine too quickly: sweating, palpitations and dizziness, usually for no longer than about 45 minutes. An internal hernia occurs in roughly 1 to 1.5 percent and can happen years later, with sudden cramping pain after eating. Anti-inflammatory painkillers (NSAIDs) are forbidden, and the contraceptive pill may become less reliable.
Advantages and points of attention: gastric bypass
Advantages
| Advantage | Explanation |
|---|---|
| Most experience | most performed operation in the Netherlands |
| Type 2 diabetes | blood sugar often improves within days |
| Reflux | usually decreases |
| Long-term results | over 90% keep at least half of excess weight off after ten years (WeightWorks) |
Points of attention
| Point of attention | Explanation |
|---|---|
| Deficiencies | lifelong WLS vitamins and 1,500 mg calcium |
| Dumping | after sugar and fat |
| Internal hernia | about 1-1.5%, even years later |
| Alcohol | faster and higher blood levels |
Cost and insurance (2026)
With a referral and indication, the pathway from screening to aftercare is covered by the basic package.
| Item | Amount or arrangement |
|---|---|
| Covered pathway | €385 deductible (2026) |
| Self-pay, WeightWorks 2026 | €10,700 all-in |
| Self-pay range in the Netherlands | roughly €7,000 to €11,000 |
| Vitamins and calcium | about €10-€15 a month |
Gastric bypass: key figures
| Feature | Value |
|---|---|
| Operation time | 90-120 minutes |
| Weight loss | about 30-40% of total body weight |
| Internal hernia | about 1-1.5% |
| Calcium after a bypass | at least 1,500 mg a day |
| Serious complications nationally (2024) | 1.4% |
Classic bypass versus mini bypass
| Feature | Gastric bypass (Roux-en-Y) | Mini gastric bypass |
|---|---|---|
| Connections | 2 | 1 |
| Operation time | 90-120 min | 60-90 min |
| Internal hernia | about 1-1.5% | below 0.12% (WeightWorks) |
| Bile reflux | rare | slightly more common |
| Weight loss | comparable | comparable |
Step by step
- Referral. GP or specialist refers you.
- Screening. Medical, psychological and dietary assessment.
- Preparation. Stop smoking, order WLS vitamins in advance.
- Surgery. Keyhole operation of 90-120 minutes.
- Aftercare. At least five years of checks with blood tests.
Read next
- Gastric sleeve as an alternative — stomach only
- Types of weight loss surgery — overview
- Gastric bypass cost and coverage — 2026
- Gastric bypass eligibility — who qualifies
Frequently asked questions about the gastric bypass
On average about 30 to 40 percent of your total body weight, with the fastest loss in the first six to twelve months. According to WeightWorks, more than 90 percent of bypass patients have lost at least half of their excess weight after ten years.
Yes, from the basic package, when you meet the criteria and have a referral. You pay your mandatory deductible of 385 euros in 2026. Lifelong vitamins are not covered.
Symptoms such as sweating, palpitations, dizziness or sleepiness when sugar or fat reaches the small intestine too quickly. Vitalys says it usually lasts no longer than 45 minutes and passes by itself; lying down helps.
Alcohol reaches your blood faster and at higher levels, and stays longer. Doctors at Ghent University Hospital increasingly advise against alcohol after bypass surgery, and a minority of patients develops alcohol problems.
No NSAIDs such as ibuprofen, naproxen or diclofenac, because they can cause an ulcer at the connection. Paracetamol is usually allowed. Always check with the prescriber.
A loop of intestine slipping through an opening created by the bypass. It occurs in about 1 to 1.5 percent of people and can happen years later. Sudden cramping abdominal pain after eating needs urgent contact with your centre.
Technically it can be reversed, but this is rarely done. More often the bypass is adjusted, for example by lengthening it or placing a MiniMizer ring when weight returns.
Usually a few days, depending on the centre and your recovery. Some hospitals discharge you the day after surgery if everything goes well.
It can be less reliable because absorption changes. Discuss a method that does not depend on the gut, such as an IUD or implant, with your GP.
The rerouting changes gut hormones that regulate blood sugar. Many people need less or no diabetes medication afterwards. This applies to type 2 diabetes; type 1 is not cured by surgery.
Call +31 6 38048347 (Mon–Fri 09:00–17:00) or email info@maagverkleining-info.nl. This page is also available in Dutch.
Sources
- Vitalys (Rijnstate): gastric bypass, dumping, FAQ
- WeightWorks: gastric bypass and mini gastric bypass
- Druglijn and VRT NWS (Ghent University Hospital): alcohol after bariatric surgery
- DATO Annual Report 2024, DICA
Search terms leading here: gastric bypass Netherlands, Roux-en-Y bypass Netherlands, gastric bypass cost Netherlands, gastric bypass drawbacks.
Author: Gijs Bodenstaff. Last reviewed: September 2026.