Before we went ahead with surgery, the question that kept coming back was not about cost or recovery time or what we’d be able to eat afterwards. It was simpler and more fundamental than any of that: is this actually safe?
We’d both been heavy for most of our adult lives. James was around 30 stone at surgery. Kirsten around 18. We’d already accepted that staying at those weights carried its own serious risks. But agreeing to a surgeon removing 75-80% of your stomach under general anaesthetic is a different kind of risk – one that feels more immediate, more deliberate, and harder to weigh up without good information.
This post is our honest attempt to answer that question clearly. We’re patients, not clinicians. We’ll tell you what we found in the published evidence, what our own experience looked like, and where to go if you want to read the primary sources yourself rather than trusting any summary – ours included.
The short answer
Gastric sleeve surgery is considered a safe procedure when performed by an experienced bariatric surgeon in an appropriate facility. The overall mortality rate is low – comparable to other common elective procedures – and the majority of patients who undergo it do not experience serious complications.
That said, “generally safe” is not the same as “risk-free.” There are real complications that occur in a minority of patients, and a small number of cases have serious outcomes. Understanding what those risks are, how likely they are, and how they compare to the risks of untreated severe obesity is the only way to make an informed decision.
What the data says: mortality and complication rates
The most cited figure for gastric sleeve mortality is around 0.1-0.3%, meaning roughly 1-3 deaths per 1,000 procedures. This is broadly in line with the risk from other common elective surgeries such as gallbladder removal or hip replacement.
For serious complications, rates vary by study and by what counts as “serious,” but figures commonly cited in bariatric literature sit in the range of 3-5% for major complications. The National Bariatric Surgery Registry, run by the British Obesity and Metabolic Surgery Society (BOMSS), publishes UK outcome data that gives a more specific picture of what happens in British practice.
The figure that tends to concern patients most is the staple line leak rate – this is where the join where the stomach was cut and stapled fails to heal cleanly, leading to leakage of stomach contents into the abdominal cavity. In experienced hands, this sits at around 1-3% and often lower. It is a serious complication that typically requires further surgery and a longer recovery, but it is rare and, when caught early, treatable.
These numbers come from published registry data and systematic reviews. The most authoritative source for UK patients is the BOMSS National Bariatric Surgery Registry. If you want to read the actual figures rather than any summary, bomss.org is the right starting point.
The main risks in detail
Every reputable bariatric programme will walk you through these in detail before surgery, and anything we say here is not a substitute for that conversation. But here is an honest overview of what the risks actually are.
Staple line leak. As described above – the most feared short-term complication. Symptoms include fever, increasing abdominal pain, and feeling unwell days after surgery. Diagnosed quickly, it is manageable. The key is not ignoring warning signs in the days after discharge.
Bleeding. Can occur during or after surgery. In most cases it is managed without consequence, but in rare cases a return to theatre is required.
Blood clots. Deep vein thrombosis (DVT) and pulmonary embolism (PE) are risks with any surgery involving general anaesthetic and reduced mobility. Bariatric patients are typically given blood-thinning medication and encouraged to walk as early as possible post-op to reduce this risk. We were walking around the ward the evening of our surgery.
Infection. Wound infection or internal infection (usually linked to a leak). Standard post-operative monitoring reduces the likelihood of this becoming serious.
Anaesthetic reaction. James had a known adverse reaction to anaesthesia – something we’d flagged thoroughly before surgery. It was managed, but it’s worth being thorough in your pre-op disclosures if you have any relevant history. You can read more about how James’s recovery went on our aftercare page.
Stricture. Narrowing of the sleeve can occasionally make eating difficult in the months after surgery. This typically responds to endoscopic dilation.
Longer-term considerations
The immediate post-operative risks tend to get most of the attention, but the longer-term picture matters too – particularly for YMYL content consumers who are making a decision they’ll live with for decades.
Nutritional deficiencies. Because you eat significantly less and the digestive process changes, absorbing adequate vitamins and minerals requires lifelong attention. Iron, B12, vitamin D, calcium, and zinc are the main ones to monitor. James ran into significant issues around month 11 – fatigue, brain fog, cold intolerance – that turned out to be nutritional in origin. We’ve written about our supplement protocol in detail in our supplements and vitamins section.
Acid reflux (GORD). Gastric sleeve surgery can worsen existing acid reflux or occasionally trigger it in patients who had none before. This is worth discussing carefully with your surgeon pre-operatively, particularly if you already have GORD – some bariatric specialists would lean toward gastric bypass rather than sleeve in those cases. We’ve written about our experience with acid reflux and omeprazole separately.
Weight regain. The sleeve does not prevent weight regain if old eating habits return. The restriction reduces over years as the body adapts, and patients who return to grazing, high-calorie drinks, or frequent snacking will regain weight. This is a behavioural risk as much as a surgical one.
Psychological adjustment. Rapid, significant weight loss reshapes how you feel about yourself, how others treat you, and how you relate to food in ways that are hard to anticipate before surgery. Some patients find the psychological adjustment harder than the physical recovery. We’ve covered this in our posts on identity after surgery and body dysmorphia.
Weighing surgery against the risks of staying obese
This is the part that often gets lost in discussions about surgical risk.
Severe obesity carries well-documented, significant health risks of its own: type 2 diabetes, cardiovascular disease, hypertension, sleep apnoea, increased cancer risk, and substantially reduced life expectancy. The question isn’t “is surgery safe?” in isolation – it’s “how does surgical risk compare to the risk of not having surgery?”
For most people who qualify for bariatric surgery under NICE guidance, the risk-benefit calculation favours surgery. The published evidence on this is substantial. But it is a calculation that has to be made individually, in conversation with a bariatric team, not from a blog post.
What we can tell you from our own experience: James’s obesity-related comorbidities – high blood pressure, pre-diabetic markers, severe sleep apnoea – had all resolved within three months of surgery. That’s not us selling the procedure. That’s what happened.
How to reduce your risk
The single most significant factor in your surgical outcome, beyond anything else, is the experience and competence of your surgeon and the quality of the facility.
In the UK, you can verify a surgeon’s credentials on the GMC specialist register and cross-check their BOMSS membership. Ask specifically how many gastric sleeve procedures the surgeon has performed in the past 12 months, and ask for that in writing. A good surgeon won’t flinch at the question.
If you’re considering surgery abroad – which is how we did it, at Weight Loss Riga in Latvia – the due diligence process matters even more because there’s no GMC register to fall back on. We’ve written about what that process looked like for us in our post on surgery abroad, including how we verified our surgeon through local sources rather than relying on English-language testimonials.
Other things that reduce risk: being honest in your pre-op assessments (including disclosing any anaesthetic history, medications, and comorbidities), following the pre-op liver reduction diet fully, committing to post-op follow-up, and not dismissing early warning signs if something feels wrong after you’re home.
Our experience
Both of us had surgery on the same day in March 2024. Neither of us had serious surgical complications, beyond James’s known anaesthetic reaction which was managed in theatre. We were discharged the following day, walking unaided, and flew home without incident.
That doesn’t mean it will go that smoothly for everyone. And we’d be doing a disservice to people reading this if we only told the straightforward version. Some people do have leaks. Some people do have significant complications. The statistics above are real. What we can say is that those things are not common outcomes, and choosing an experienced team substantially reduces the likelihood of them happening.
Two years on, both of us are healthier than we’ve been in decades. The risks were real. For us, they were worth taking.
Sources cited in this post: NHS – Weight loss surgery: risks
BOMSS – National Bariatric Surgery Registry (NBSR) safety outcomes data
NICE CG189 – Obesity: identification, assessment and management
Welbourn R et al. – Laparoscopic sleeve gastrectomy: a systematic review (Annals of Surgery, 2019)
- NHS, “Weight loss surgery”: https://www.nhs.uk/conditions/weight-loss-surgery/
- NICE clinical guideline CG189, “Obesity: identification, assessment and management”: https://www.nice.org.uk/guidance/cg189
- British Obesity & Metabolic Surgery Society (BOMSS), including the National Bariatric Surgery Registry: https://bomss.org/
- General Medical Council, specialist register: https://www.gmc-uk.org/registration-and-licensing/the-medical-register
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: 23 August 2024 | Last Reviewed: 27 June 2026 | Next Planned Review: 27 December 2027