Am I a candidate for weight loss surgery?
Most people start with this question, and most of the answers online are either out of date or reduced to a single number. This page explains how eligibility is actually assessed: what BMI shows, what the current guidelines say, why your insurer may use different criteria, and what else goes into the decision.
Book a free consultationMedically reviewed by David G. Davtyan, MD, FACS, FICS, FASMBS · Last reviewed September 24, 2026
Calculate your BMI
Body mass index (BMI) is your weight divided by the square of your height. Enter yours to see the number and its CDC adult category. Nothing you type leaves this page.
The categories are the CDC's, for adults aged 20 and over. Children and teens are assessed differently (see adolescents).
What BMI does and does not tell you
The CDC describes BMI as a quick, low-cost screening measure for underweight, overweight and obesity. Its adult categories are:
| BMI | CDC adult category |
|---|---|
| Less than 18.5 | Underweight |
| 18.5 to less than 25 | Healthy weight |
| 25 to less than 30 | Overweight |
| 30 to less than 35 | Class 1 obesity |
| 35 to less than 40 | Class 2 obesity |
| 40 or greater | Class 3 obesity (severe obesity) |
What BMI cannot do is describe you as an individual. It does not distinguish between fat, muscle and bone, and does not show what kind of fat you carry or where you carry it. For that reason the CDC says BMI should be read alongside your medical history, health behaviors, a physical exam and laboratory results rather than on its own (CDC, About BMI; CDC, Adult BMI Categories).
In a weight loss evaluation, BMI opens the conversation; your health conditions and history matter as much. The practice's own explainer is What's BMI, and how important is it?, and the obesity overview covers the disease itself. For how weight affects specific conditions, see obesity and related health conditions. Unfamiliar terms are defined in the bariatric glossary.
The current clinical guidelines
In 2022 the American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) published joint indications for metabolic and bariatric surgery, replacing the 1991 National Institutes of Health (NIH) consensus statement. In summary:
- BMI of 35 or more: surgery is recommended, whether or not you have obesity-related conditions.
- BMI of 30 to 34.9 with metabolic disease (type 2 diabetes, for example): surgery should be considered.
- BMI of 30 or more without metabolic disease: ASMBS says surgery should be considered for people who have not achieved substantial or durable weight loss, or improvement in obesity-related disease, with nonsurgical methods.
- People of Asian descent: the guidelines say BMI thresholds should be adjusted in the Asian population, so that a BMI above 25 suggests clinical obesity and people with a BMI above 27.5 should be offered surgery, because diabetes and cardiovascular disease are more common at a lower BMI in this population.
Sources: ASMBS/IFSO 2022 indications; ASMBS, October 2022.
These say when surgery should be offered or considered, not that it is right for you; that depends on the rest of the evaluation below. If you have type 2 diabetes, how bariatric surgery may improve type 2 diabetes and gastric bypass for type 2 diabetes go into more detail. If you are already taking a GLP-1 medication, GLP-1 medications before bariatric surgery explains how that fits with the guidelines.
Why your insurer may use older criteria
The 1991 NIH statement limited surgery to people with a BMI of at least 40, or 35 or more with at least one obesity-related condition. When the new indications were published in 2022, ASMBS noted that the 1991 standards were still the ones most insurers and doctors relied on (ASMBS, October 2022).
That is why you will still see "BMI 40, or 35 with a comorbidity" in many places, including some older pages on this site. It is often what a health plan's coverage policy says, even though it is no longer the clinical guideline, and plans may ask for more, such as documented weight history. Each plan sets its own rules, so the reliable answer is your own policy.
The practice checks benefits for you. How coverage decisions are made and what the options are if your plan says no are covered in the insurance and financing hub. See also what insurance typically covers for gastric bypass.
Each option has its own BMI range
The ASMBS/IFSO guidelines are about surgery. Each device is approved by the FDA for a specific group of patients, and those ranges do not match the guidelines or each other.
- Allurion swallowable balloon: adults aged 22 to 65 with obesity and a BMI of 30 to 40 who have had at least one unsuccessful attempt at a weight loss program (FDA approval, P250023).
- Orbera balloon: adults with obesity and a BMI of 30 to 40 who have not succeeded with more conservative approaches such as supervised diet and exercise (FDA approval, P140008).
- Endoscopic sleeve gastroplasty (ESG, the Accordion procedure): the FDA authorized the Apollo ESG system for adults with obesity and a BMI of 30 to 50 who have not been able to lose weight, or keep it off, through more conservative measures (FDA De Novo order, DEN210045).
- Lap-Band: the device's labeling covers adults with a BMI of at least 40, or at least 30 with one or more obesity-related conditions, who have not succeeded with more conservative weight reduction alternatives (FDA approval, P000008/S017).
Weight loss medications have their own prescribing criteria, covered in the weight loss medication hub. For how the options compare, see comparing your weight loss options.
The practice's pages on each option's candidacy:
The rest of the evaluation
Meeting a BMI threshold is where the assessment begins, not where it ends. The ASMBS/IFSO paper describes a team-based evaluation, drawing on medical, surgical, psychological and nutritional expertise, with the decision on surgical readiness resting mainly with the surgeon (ASMBS/IFSO 2022 indications). In practice that usually covers:
- Your medical history. Current conditions and medications, previous operations, and anything that affects the safety of anesthesia or a particular procedure.
- Your weight history. What you have tried before and what worked. Insurers often ask for it too.
- A psychological evaluation. The guidelines describe it as a way to identify and support issues such as disordered eating, severe uncontrolled mental illness or active substance use, and to understand how you are likely to cope with the changes surgery brings.
- A nutrition assessment. A registered dietitian can review eating patterns and find and correct vitamin or mineral deficiencies before surgery.
Which of these apply to you depends on the procedure and on your insurer.
- Weight loss consultation: what to expect
- Mental and emotional preparation before bariatric surgery
- Psychiatric illness and weight loss after bariatric surgery
- Preparing for bariatric surgery
- Do you need to stop your GLP-1 before surgery?
- Getting a second opinion on bariatric surgery
- Nutrition before and after bariatric surgery
- The weight loss surgery journey, stage by stage
If you have had weight loss surgery before, start with the bariatric revision hub. If you are thinking about a future pregnancy, see pregnancy and fertility after bariatric surgery.
Adolescents
Children and teens are not assessed with the adult BMI categories. Their BMI is compared with others of the same age and sex, as a percentile. The American Academy of Pediatrics' 2023 clinical practice guideline says that teens aged 13 and older with severe obesity, defined as a BMI at or above 120% of the 95th percentile for age and sex, should be evaluated for metabolic and bariatric surgery (AAP, 2023). The 2022 ASMBS/IFSO indications likewise say that appropriately selected children and adolescents should be considered for surgery (ASMBS/IFSO 2022 indications).
Being evaluated is not the same as having surgery. If you are a parent, your child's pediatrician is the right place to start.
Candidacy, procedure by procedure
Some of the older pages below describe the 1991 criteria; where they differ, the guidelines summarized above are current.
Weight loss surgery in general
- Who qualifies for bariatric surgery?
- Bariatric surgery requirements: a complete checklist
- Bariatric surgery overview
- Frequently asked questions
By procedure
¿Soy candidato? — en español
La práctica atiende en español en las cuatro oficinas y publica esta información en español:
- ¿Soy candidato para la cirugía bariátrica?
- La evaluación psicológica bariátrica: qué preguntan y por qué
- Su primera consulta bariátrica en español, paso a paso
- Medicamento o cirugía: cómo se decide
- Cirugía bariátrica después de los 60: qué se evalúa
- Fumar, vapear y alcohol antes de la cirugía
- Medi-Cal y Medicare para cirugía bariátrica
- Todo el contenido en español
Where Dr. Davtyan sees patients
Spanish is spoken at all four offices. The first consultation with Dr. Davtyan is free and commits you to nothing.
Talk it through with Dr. Davtyan
No page and no calculator can tell you whether a procedure is right for you. A consultation looks at your full history, explains which options fit it, and checks what your own insurance requires. The first consultation is free and commits you to nothing.
Sources
- CDC — About Body Mass Index (BMI)
- CDC — Adult BMI Categories
- Eisenberg D, et al. 2022 ASMBS and IFSO Indications for Metabolic and Bariatric Surgery. Obesity Surgery 2023;33:3–14 (PMC full text)
- ASMBS — After 30 Years, New Guidelines for Weight-Loss Surgery (October 2022)
- FDA — Premarket approval letter, Allurion Gastric Balloon System (P250023)
- FDA — Premarket approval letter, Orbera Intragastric Balloon (P140008)
- FDA — De Novo classification order, Apollo ESG and Apollo Revise systems (DEN210045)
- FDA — Premarket approval database, Lap-Band Adjustable Gastric Banding System (P000008/S017)
- American Academy of Pediatrics (HealthyChildren.org) — Caring for Kids With Obesity: AAP Updates Evaluation & Treatment Guideline
This page is general information about how eligibility for bariatric and endoscopic weight loss treatment is usually assessed. It is not medical advice, and the BMI calculator does not diagnose any condition or determine whether you are eligible for any treatment. Guidelines, device labels and insurance policies change and differ from one another. Whether a treatment is appropriate for you can only be decided after an individual medical evaluation.
