Before surgery
Who may be a candidate for bariatric surgery?
BMI is a starting point; associated conditions, previous treatments and readiness for follow-up also affect the decision.
Educational adaptation of an article from the previous website • Content updated: 27 September 2026
What do newer criteria say?
The 2022 joint ASMBS/IFSO guidelines recommend metabolic and bariatric surgery at BMI 35 or above, regardless of associated conditions. At BMI 30–34.9, surgery may also be considered in specific circumstances, including metabolic disease or insufficient, unsustained results from nonsurgical treatment. Local insurance and healthcare rules may differ.
Sleeve gastrectomy concept
AI-created conceptual artwork; not a patient result or an exact surgical diagram.
Explore the educational diagram and sources
Educational illustration
Sleeve gastrectomy changes the stomach into a narrow tube; this is a procedure schematic.
An educational schematic, not a patient result or a personalized treatment plan. Original labels may be in another language.
Open larger image ↗Source & licence
Kwipédl Cyop
Sleeve gastrectomy diagram (according IFSO and French HAS).svg · CC BY-SA 4.0
Simplified educational image; not to scale.
Is BMI alone enough?
No. These criteria do not automatically approve a person for surgery. The doctor assesses heart and lung health, diabetes, reflux, sleep apnoea, surgical history and anaesthetic risk. Nutrition and the ability to maintain follow-up also matter. Expected benefits and risks are assessed individually.
What role does age play?
One fixed upper age limit is not appropriate for all adults; functional status, frailty and associated illnesses matter. Adolescents need assessment and selection by a specialist team using specific criteria. Adult criteria should not be applied to children or adolescents without specialist assessment.
Explore the educational diagram and sources
Educational illustration
Roux-en-Y gastric bypass: a small stomach pouch connects to a rerouted segment of small intestine.
An educational schematic, not a patient result or a personalized treatment plan. Original labels may be in another language.
Open larger image ↗Source & licence
Blausen.com staff (2014), Medical gallery of Blausen Medical 2014, WikiJournal of Medicine 1(2), doi:10.15347/wjm/2014.010
Blausen 0776 Roux-En-Y 01.png · CC BY 3.0
Simplified educational image; not to scale.
Preparing for life after surgery
Surgery starts a care journey. Understanding dietary changes, prescribed supplements, regular tests and follow-up visits is essential. Eating disorders, mental health problems or substance use should be assessed supportively and treated when needed, with the aim of preparation and safer care.
What should you bring to a consultation?
Prepare your weight history, previous treatments and medicines, current medication list and results concerning associated conditions. Ask about nonsurgical options, the proposed procedure, possible complications and access to the care team after discharge. Treatment should be a shared, informed decision.
This article provides general information. Treatment and nutrition plans must fit your procedure, associated conditions and individual circumstances.
Sources and article history
Adapted and rewritten from an older article. Absolute claims, outdated prices and advice needing correction have not been republished unchanged.