Kirsten has lived with Crohn’s disease since long before either of us had heard of a gastric sleeve, which meant kidney stones were already a background risk we understood before her surgery ever came up. Adding a sleeve on top of that did not feel like a new conversation so much as an extension of one we were already having with her gastroenterologist. If you do not have a condition like Crohn’s, this might be a genuinely new risk to get your head around, so it is worth explaining properly.
Is there actually a link between sleeve surgery and stones
Yes, though the risk is lower than for more malabsorptive procedures like gastric bypass. Research into stone development after bariatric surgery points to changes in twenty four hour urine profiles as the main driver, including increased urinary oxalate, lower urine volume, and reduced urinary citrate, a substance that normally helps prevent stones from forming in the first place. Sleeve gastrectomy is a purely restrictive procedure, so this risk sits at the lower end of the spectrum compared to bypass, but it is not zero.
Why Crohn’s changes the picture
Conditions that already affect how the gut absorbs fat and oxalate, Crohn’s disease being a well-known example, raise the baseline risk of oxalate-related kidney stones independently of any surgery. Layering a sleeve on top of an existing bowel condition means paying closer attention than the average patient might need to, and it is exactly why we have kept Kirsten’s gastroenterologist and her bariatric team aware of each other rather than treating them as two separate, unconnected parts of her care.
Why a smaller stomach raises the risk for anyone
With a stomach reduced to around fifteen to twenty percent of its original size, staying properly hydrated takes real, ongoing effort, since you simply cannot drink a large volume in one sitting the way you could before surgery. Lower fluid intake means more concentrated urine, and concentrated urine gives minerals more opportunity to crystallise into stones. It is a quiet, unglamorous risk that does not get talked about nearly as often as vitamin deficiencies, but it is just as real.
What actually helps
Consistent hydration is the single biggest factor within your control, and that means treating water intake as a deliberate, spaced-out habit through the day rather than something you try to catch up on in the evening. For Kirsten specifically, that has meant carrying water everywhere as a genuine non-negotiable rather than an afterthought, and mentioning any new back or side pain to her care team immediately rather than waiting to see if it passes on its own.
Signs worth taking seriously
Sharp pain in the back or side, blood in the urine, or pain that comes in waves and moves toward the groin are classic signs of a kidney stone and worth getting checked urgently rather than waiting out. Because dehydration is so easy to slip into with a sleeve, these symptoms deserve to be taken seriously the first time, not dismissed as just another post-surgery discomfort to push through.
Sources
Peer reviewed research on nephrolithiasis and renal stone risk after bariatric surgery, published in journals including the Journal of Urology and related surgical literature.
About this content
This blog is written by James and Kirsten, a couple from the UK who had gastric sleeve surgery together in March 2024.
We started this blog because we couldn't find any sources of content that details before surgery, the surgery and then life post surgery - so we decided to write one ourselves.
Everything on this site is based on our own experience and the research we have done along the way. It is not medical advice. Gastric sleeve surgery is a serious procedure and every patient's journey is different. Please always consult your own bariatric team or GP before making any decisions about your health or treatment.
Some posts on this site may contain featured or sponsored content, or affiliate links. Where this is the case, it will always be clearly stated at the top of the article. Our opinions are always our own.
Publish Date: 30 July 2026 | Last Reviewed: 9 August 2026 | Next Planned Review: 9 February 2028