- Weight loss holds well up to about ten years (Van Gaal).
- Over 90% keep half of excess weight off after 10 years (WeightWorks).
- Some regain after five to ten years is common.
- Late risks: deficiencies, internal hernia, kidney stones, gallstones.
- Yearly blood tests remain important for life.
How well does weight loss hold in the long term?
The fastest loss is in the first six to twelve months; weight stabilises after one and a half to two years. Prof. Luc Van Gaal describes that the loss holds well for up to about ten years; there is less data for the period after that.
WeightWorks reports strong long-term figures for the bypass: after ten years more than 90 percent of patients have lost at least half of their excess weight, and most still have a healthy weight after twenty years. Some weight gradually returns after five to ten years for part of the group.
Late physical effects
An internal hernia after a classic bypass occurs in about 1 to 1.5 percent and can happen long after surgery, with sudden cramping pain after eating; after a mini bypass it is below 0.12 percent according to WeightWorks. After a bypass the risk of kidney stones is higher, especially if you had them before. After fast weight loss gallstones are more common; the Nederlandse Obesitas Kliniek mentions about twenty percent.
Deficiencies years later
Deficiencies are the most sneaky long-term risk: people who stop taking vitamins years later only notice when symptoms appear, such as fatigue, hair loss or tingling. Yearly blood tests after the five-year aftercare, via your GP or centre, catch them early.
Research into mental effects and quality of life in the long term is still a gap in the field.
What supports lasting results
Advantages
| Advantage | Explanation |
|---|---|
| Daily vitamins | for life |
| Yearly blood tests | also after five years |
| Protein and exercise | keep muscle |
| Early action on regain | dietitian and team |
Points of attention
| Point of attention | Explanation |
|---|---|
| Grazing and liquid calories | main causes of regain |
| Stopping vitamins | late deficiencies |
| Cramping pain | possible internal hernia |
| Upper abdominal pain | possible gallstones |
Cost and insurance (2026)
Long-term costs are mainly vitamins and yearly blood tests.
| Item | Amount or arrangement |
|---|---|
| Vitamins and calcium | €120-€180 a year |
| Yearly blood test via GP | lab costs count towards deductible |
| Revision with medical reason | basic package |
Long-term results: key figures
| Feature | Value |
|---|---|
| Weight loss holds well | up to about 10 years |
| Half of excess weight off after 10 years (bypass) | over 90% |
| Internal hernia after bypass | about 1-1.5% |
| Gallstones after fast weight loss (NOK) | about 20% |
| Stabilisation | after 1.5-2 years |
Late effects and what to do
| Effect | Signs | Action |
|---|---|---|
| Deficiency | fatigue, hair loss, tingling | blood test |
| Internal hernia | sudden cramping pain after eating | contact centre urgently |
| Gallstones | pain in upper right abdomen | GP or centre |
| Regain | gradual weight increase | dietitian, team |
Step by step
- Years 0-2. Fast loss, then stabilisation.
- Years 2-5. Aftercare at the centre.
- After 5 years. Yearly blood tests via GP.
- Regain?. Contact dietitian or centre early.
- Warning signs. Cramping pain, jaundice, severe fatigue.
Read next
- Risks and disadvantages — all phases
- Revision surgery — when results decline
- Aftercare — five years
- Metabolism after surgery — set point
What to do when weight returns
Act early rather than waiting. Review your eating habits with a dietitian: grazing, liquid calories and eating without hunger are common causes. The team may also discuss supervised medication, and in some cases revision surgery, such as lengthening a bypass or placing a MiniMizer ring, which Vitalys offers.
Staying connected after the aftercare period
When the five-year aftercare ends, your GP becomes your main contact. Make sure your GP knows which operation you had and which supplements you take, and ask for a yearly blood test. If you move abroad, bring a summary of your operation and recent results.
Kidney stones and gallstones in practice
Drink enough water spread over the day, outside mealtimes, to lower the risk of kidney stones. Report severe pain in the side or back, or blood in the urine, to your GP. For gallstones, watch for pain in the upper right abdomen, especially after fatty meals, and yellowing of the skin or eyes; contact your GP or centre promptly.
Setting yourself up for the next ten years
Keep the habits that work: protein first, six small meals, no drinking with meals, daily movement and vitamins every day. Weigh yourself regularly but not obsessively, and act on a trend rather than a single number. Keep a yearly reminder for your blood test, and tell every new doctor about your operation.
Most importantly, stay in contact with healthcare when something changes. Early help for regain, low mood or physical complaints is far more effective than waiting.
Frequently asked questions about long-term results
Weight loss holds well for up to about ten years for most people, with less data after that. Some regain after five to ten years is common.
WeightWorks reports that most bypass patients still have a healthy weight after twenty years.
Mostly because eating habits change: grazing, liquid calories and eating without hunger.
Yes. It occurs in about 1 to 1.5 percent after a classic bypass and can happen long after surgery.
Yes, yearly, because deficiencies can still develop.
After a bypass the risk is higher, especially if you had them before.
After fast weight loss gallstones are more common; the NOK mentions about twenty percent.
Dietary review, possibly medication, and in some cases revision surgery.
Research into mental effects and quality of life in the long term is still limited.
Your GP, supported by the centre if problems arise.
Call +31 6 38048347 (Mon–Fri 09:00–17:00) or email info@maagverkleining-info.nl. This page is also available in Dutch.
Sources
- Prof. Luc Van Gaal (Antwerp University Hospital): long-term results
- WeightWorks: gastric bypass and mini gastric bypass
- Nederlandse Obesitas Kliniek: gallstones
- Vitalys (Rijnstate): redo surgery and FAQ
Search terms leading here: long term results weight loss surgery, gastric bypass 10 years later, weight regain after bariatric surgery.
Author: Gijs Bodenstaff. Last reviewed: September 2026.