Who Is Bariatric Surgery Actually For, and How Eligibility Is Decided

Written by Dr. Ashutosh A Shah, M.B.B.S., M.S., M.Ch., D.N.B., Board Certified Plastic and Reconstructive Surgeon, Body Reform Clinic, Surat. Reg. no. [REG NO]. 22+ years in plastic and reconstructive surgery.

Medically reviewed by Dr. Ashutosh A Shah · Published 29 September 2026 · Last reviewed 29 September 2026

Bariatric surgery eligibility is decided against published criteria rather than by weight alone, and it is not suitable for every person who is overweight. Assessment covers body mass index, weight related conditions, previous attempts at weight loss, and whether someone can follow the lifelong changes it requires.

Two things are worth saying before anything else.

The first is that eligibility is not a judgement about you. It is a set of published criteria, written down by surgical societies, that you are entitled to read for yourself. The second is that this clinic does not perform bariatric surgery. It treats people before and after it. That is why this page quotes the criteria and names who to see, rather than arriving at a booking form.

Why is the answer not simply a weight?

Because the same weight means different things in different bodies, and because the criteria were written to find the people who benefit rather than the people who weigh most.

A number on a scale takes no account of what that weight is doing to you. Two people at an identical body mass index can be in entirely different clinical positions: one with uncontrolled diabetes and sleep apnoea, one with neither. The guidelines treat those two differently, and they are right to.

There is a second reason, and it matters specifically here. Body mass index does not mean the same thing across populations. The 2022 ASMBS and IFSO guidelines state it directly: "In the Asian population the prevalence of diabetes and cardiovascular disease is higher at a lower BMI than in the non-Asian population."

The Indian guidelines make the same point about consequences: the Obesity and Metabolic Surgery Society of India writes that "Asians, and in particular the Indian population needs a more aggressive approach in treating obesity and its co-morbidities as it is associated with higher morbidity and mortality at a relatively lower BMI."

So a threshold copied from an American or British page is not the threshold that applies to you, and reading one is a common reason people conclude they do not qualify when they may.

What do the published bariatric surgery eligibility criteria actually say?

They set thresholds, and the thresholds differ between guidelines. Both sets are quoted here in full so you can see the difference rather than take one number on trust.

The Indian criteria. OSSI sets three:

• "BMI above 37.5 kg/m2 without co-morbidities."
• "BMI above 32.5 kg/m2 with obesity related co-morbidities"
• "BMI > 30 kg/m2 with life threatening obesity related disorders like uncontrolled diabetes, cardiovascular disease / cardiomyopathy and severe obstructive sleep apnoea."

The international criteria. ASMBS and IFSO state that "Metabolic and bariatric surgery (MBS) is recommended for individuals with a body mass index (BMI) >35 kg/m2, regardless of presence, absence, or severity of co-morbidities." For Asian patients they go lower still: "BMI thresholds should be adjusted in the Asian population such that a BMI >25 kg/m2 suggests clinical obesity, and individuals with BMI >27.5 kg/m2 should be offered MBS."

The UK position, for comparison. The NHS says surgery may be available if "you have a body mass index (BMI) of 40 or more", or if "you have a BMI between 35 and 40 and a condition that might improve if you lost weight". Those are UK service criteria rather than Indian clinical ones, and they are the numbers most often quoted at Indian readers by pages that have not checked.

Now read what that comparison means. Those guidelines do not agree with each other. Somebody who does not meet the Indian threshold may meet the international one, and a page that quotes only the number that suits it is not telling you the whole picture. This is a conversation to have with a bariatric surgeon, with both sets in front of you, rather than a verdict to accept from a website.

Numbers are only the entry point. The table below is what an assessment actually covers.

Read the third column. Almost none of it is the surgeon, and none of it is a website.

Why do weight related conditions change the answer?

Because the operation is offered to treat disease rather than to reduce a number, and a body already showing damage has more to gain and less time to wait.

That logic is visible in the criteria themselves. OSSI's thresholds fall as the conditions get more serious: highest with no co-morbidities, lower with them, lowest of all for "life threatening obesity related disorders like uncontrolled diabetes, cardiovascular disease / cardiomyopathy and severe obstructive sleep apnoea."

Two consequences worth knowing:

• A diagnosis can move you into eligibility. Someone who did not qualify a year ago and has since developed diabetes may qualify now. That is not good news, but it is worth knowing rather than discovering late.
• Undiagnosed conditions cannot count. Sleep apnoea in particular goes unrecognised for years. If it has never been tested for, it cannot be weighed in your favour.

ASMBS and IFSO frame the underlying point in a sentence worth holding on to: "Severe obesity is a chronic disease requiring long-term management after primary MBS." Chronic disease is the category. The surgery is a treatment for it.

What is asked about previous attempts, and why is that not a judgement?

You will be asked what you have tried and what happened, and it is worth knowing that failing to lose weight before surgery is not supposed to disqualify you.

This is the part people dread most, and the guidelines are more on your side than you might expect. ASMBS and IFSO are unusually blunt about it: "While there has been initial enthusiasm for weight loss prior to surgery, there are no data to support the practice of insurance-mandated preoperative weight loss; this practice is understood to be discriminatory, arbitrary, and scientifically unfounded, contributing to patient attrition, unnecessary delay of lifesaving treatment, and progression of life-threatening comorbid conditions."

Read the words they chose. Discriminatory. Arbitrary. Scientifically unfounded. That is a surgical society describing a hurdle patients are routinely put through.

So why ask at all? Because the history is useful for different reasons entirely:

1. It shows the pattern. Weight lost and regained repeatedly tells the team something about physiology, not about willpower.
2. It shows what has not been tried. Occasionally something reasonable has been missed, including supervised medical treatment.
3. It shows what you can sustain. Which matters for what comes after, not for whether you deserve the operation.

Answer it honestly, including the parts that did not go well. Nobody assessing you properly is keeping score.

What is assessed that has nothing to do with weight?

Whether you can safely have a general anaesthetic and abdominal surgery, what your nutritional status already is, and whether anything about eating or mental health needs attention first.

These are the parts people do not expect, and they are the parts that most often delay a date:

• Anaesthetic and surgical fitness. Heart, lungs and airway. This is a real operation on the digestive tract, not a procedure.
• Existing deficiencies. Absorption changes after some operations, so anything already low tends to get lower. Correcting it beforehand is easier than correcting it after.
• Eating patterns. Certain patterns are better addressed before an operation that changes how much you can eat at once.
• Mental health and support. Not a test of character. A practical question about who is around you afterwards.
• Understanding what is permanent. Some of what is done cannot be undone, and the assessment checks that this has landed.

None of these is designed to catch you out. Each one is a thing that goes wrong often enough afterwards that teams now look for it first.

Who is bariatric surgery not suitable for?

People who cannot safely undergo the operation, people for whom something treatable has not yet been addressed, and people who are not in a position to attend the follow up it requires.

Stated plainly, because vagueness here helps nobody:

1. Anyone not fit for a general anaesthetic or major abdominal surgery. This is a clinical assessment and it is not negotiable by preference.
2. Anyone whose weight has an untreated medical cause that has not yet been looked for. Treating that comes first.
3. Anyone with an active, untreated eating disorder or unstable mental health. Addressed first, and addressing it is not a refusal.
4. Anyone with active substance dependence, which changes both the operative risk and what follows.
5. Anyone who cannot commit to lifelong follow up. OSSI lists this among its criteria in those terms: "Patients motivated to lose weight and commitment to long term follow up".
6. Anyone seeking it for appearance. That is a different subject and a different set of operations, set out on our post about the difference between weight loss surgery and body contouring.

Note that most of these are temporary rather than permanent. Not suitable now is a different sentence from not suitable ever, and it is the more common one.

Why is it a lifelong change rather than an operation?

Because the operation changes how you eat and absorb permanently, and because the condition it treats does not end when the wound heals.

ASMBS and IFSO put the principle in one line: "Severe obesity is a chronic disease requiring long-term management after primary MBS." The phrase that matters there is after. The management continues.

The NHS names the commitment as part of who can have the surgery in the first place, saying it is available if "you agree to make healthy lifestyle changes and attend regular check-ups after surgery". Attendance is in the criteria, not in the small print.

What that looks like in practice:

• Follow up appointments that do not stop. They reduce in frequency and they do not end.
• Blood tests, indefinitely. Because deficiencies develop quietly and are far easier to correct early.
• Supplementation as directed by your team, which is not optional and is not the same for everyone.
• Eating differently, permanently. The operation makes that easier rather than automatic.

Anyone presenting this as a one-off procedure is describing something other than bariatric surgery.

What happens if you are not eligible yet?

Usually something, and usually sooner than people expect. Not meeting a surgical threshold is not the end of obesity treatment, it is a different branch of it.

What generally follows:

• Supervised medical treatment, which has changed considerably and is now a serious option in its own right rather than a consolation.
• Treating what has not been treated. Undiagnosed sleep apnoea, thyroid problems or medication effects can all be contributing.
• Reassessment later. Criteria are read against your current position, and positions change.
• Getting the non-weight items sorted, so that if surgery does become appropriate, nothing delays it a second time.

The full range of non-surgical options, and where each one fits, is set out on our post about obesity treatment and what actually works.

What is this page not, and who should you see instead?

It is not an eligibility decision, and it is not written by a clinic that performs the operation. Body Reform Clinic does not do bariatric surgery.

That is worth being direct about, because the internet on this subject is almost entirely written by people selling the procedure. What this clinic does is the part either side of it: supervised medical weight loss and metabolic care before, and the body contouring that follows major weight loss after.

So who should you actually see?

1. A bariatric surgeon, for the eligibility decision itself. Only an assessment by the team that would operate can answer it.
2. Your own doctor first, if that is easier, for a referral and for the conditions in section three to be tested for properly.
3. A physician or endocrinologist, if the picture is mainly metabolic and surgery is not yet on the table.

What you can reasonably do with this page is take the quoted criteria to whoever you see and ask which applies to you and why. That is a fair question, and the answer should not be a number read off a chart without the rest of the assessment behind it.

How is this handled at Body Reform Clinic, Surat?

By being clear about which part of the journey we are, and by not pretending to be the part we are not.

In our practice in Surat, the most common version of this conversation is someone who arrived expecting to be assessed for the operation and has to be told that this is not where that happens. They are often relieved rather than disappointed, because they have usually spent weeks on pages that never made that distinction and they now know where to go.

The second most common is someone who had the operation years ago, stopped attending follow up because nothing felt wrong, and has come in about loose skin. Their nutritional status is the first thing we look at, and it is frequently the reason surgery has to wait.

Where we do have a part to play, it is supervised medical weight loss and metabolic support beforehand, and body contouring once weight is stable afterwards. What that later stage involves is set out on our post about body contouring after bariatric surgery, and the staged pathways are described under our programmes.

If the honest answer is that you need a different surgeon, that is the answer you will get.

Next step

If you are trying to work out whether you qualify, the useful step is an assessment by a bariatric team rather than a threshold read off a page. If the metabolic side or the body contouring side is what you need, that is what this clinic does, and you can arrange a consultation to work out which part of the picture you are in.

This page is for education and is not an eligibility assessment. Body Reform Clinic does not perform bariatric surgery. Every threshold quoted here belongs to the guideline named beside it and is reproduced so that you can take it to the team assessing you. Discuss your own situation with a bariatric surgeon or your own doctor.

About Dr. Ashutosh Shah

Dr. Ashutosh Shah, M.S., M.Ch. (Plastic Surgery), has over 22 years of experience in body contouring after weight loss. He leads Elegance Clinic, Surat, with centres at Adajan and Vesu, and is known for honest counseling and natural looking results.