Private gastric bypass surgery in the UK, by a consultant bariatric surgeon.

Broadly: a BMI of 40 or more, or 35 or more with a significant obesity-related condition such as type 2 diabetes, obstructive sleep apnoea, hypertension or joint disease. Under updated NICE NG246 guidance, a BMI of 30 or more with recent-onset type 2 diabetes can also be considered. You also need to have engaged with a Tier 3 weight-management programme and be fit for a general anaesthetic and lifelong follow-up.

Both are excellent operations. A bypass edges ahead for durable type 2 diabetes remission, for significant reflux or Barrett’s, and often for very high BMIs. A sleeve is simpler, has a lower complication rate, no anastomosis and less lifelong nutritional risk. The right answer depends on your BMI, your medical conditions and your surgeon’s experience — this is a shared decision, not a formula.

Most patients lose 30 to 35 per cent of their total body weight in the first twelve to twenty-four months. At ten years the average is nearer 25 to 30 per cent, and around ten to thirty per cent of patients regain a meaningful amount. Weight loss is not linear — it plateaus, and long-term success depends on diet, activity and follow-up rather than the operation alone.

Roughly £11,000 to £16,000 for a laparoscopic Roux-en-Y bypass, £14,000 to £18,000 for a robotic case, and £14,000 to £19,000 for a SADI-S. Revisional surgery from a previous band or sleeve is usually £13,000 to £22,000. We confirm a firm quote — including MDT workup, hospital stay and the first year of follow-up — within one working day.

A two to four week very-low-energy diet (typically Optifast or Slimfast, around 800 to 1,000 kcal per day) that shrinks the left lobe of the liver. This gives the surgeon safe laparoscopic access to the stomach and reduces the risk of conversion to open surgery. Skipping it is not optional — it materially changes how safe the operation is.

One to two nights in hospital, back to a desk job in two to four weeks, no heavy lifting for six weeks, light gym at four weeks and heavier training at eight to twelve weeks. The diet stages — liquid, puree, soft, solid — run over the first six to eight weeks and are the part most patients underestimate.

Yes. A bypass reduces absorption of iron, calcium, vitamin D and — critically — vitamin B12. Lifelong daily multivitamin with iron, calcium and vitamin D, plus three-monthly intramuscular B12, is the minimum. Blood tests at least yearly. This is not optional — deficiencies caused by non-adherence are the commonest late problem we see.

Yes, and outcomes are generally better than pregnancy at severe obesity. But you should avoid conception for twelve to eighteen months after surgery — the rapid weight-loss window carries a risk of a small-for-gestational-age baby and nutritional stress. Reliable contraception, including a non-oral method, matters during that window.

Severe abdominal pain, particularly intermittent right upper or peri-umbilical pain months to years after a bypass (internal hernia), any fever with pain in the first weeks (leak or infection), black or vomited blood (bleeding or marginal ulcer), and severe repeated hypoglycaemia (late dumping). All of these are same-day medical problems, not next-week clinic problems.