Preparation and assessment before obesity surgery

Why prepare?

Obesity surgery permanently changes the way you eat and requires lifelong follow-up. The Swiss guidelines therefore call for a structured preparation period of at least three months between the first contact and the operation¹. This time is used to complete the assessment, to give you information and to let you think things over.

Before surgery can be considered, two years of weight management, on your own and/or with professional support, are needed. Follow-up at the Centre counts towards these two years: coming to the Centre does not reset the clock.

For reimbursement, basic health insurance requires that appropriate weight-loss treatment for two years has not been effective^{2, 1}. The team checks with you that the treatments you have followed meet this condition; a personal effort is not automatically sufficient.

The main steps of the assessment

Swiss guidelines set out the minimum content of the assessment¹:

Other tests may be added depending on your situation. My surgical assessment pathway: the document to read and print

The Centre’s pathway is adapted to your situation: not every assessment is needed for everyone, and their order is arranged with you.

• Blood testsIncluding vitamins and minerals.
• Dietary assessment
• Psychological or psychosomatic assessment
• GastroscopyWith testing for Helicobacter pylori.
• Assessments depending on your situationRespiratory, gynaecological; cardiac if needed; dental check-up if needed.

The decision is taken jointly by the multidisciplinary group, with you.

How is the decision made?

The choice of treatment is discussed with you and the multidisciplinary team. The decision is made collectively, taking into account your health, your expectations and your preferences. You receive written information about the proposed operation and you give your consent in writing¹. The assessment may also conclude that another form of care is better, or that it is better to wait. You can stop the care pathway at any time.

What you can do yourself

• Smoking. Stopping smoking is advised. This is discussed with you during the preparation, and help can be offered.
• Weight. Starting to lose weight during the preparation can make the operation easier, in particular by reducing the size of the liver³. It is not a mandatory condition: this goal is discussed during your preparation.
• Medicines. Bring the full list of your medicines. If you take semaglutide or tirzepatide, let us know: these medicines slow down the emptying of the stomach, which matters for the anaesthetic⁴.
• Contraception. Pregnancy should be avoided during the preparation and in the months following the operation: talk about it during the assessment.

Frequently asked questions

What is the purpose of psychological support before the operation?

It helps prepare you for the changes that come with the operation, identify your needs and offer suitable support.

What next?

If this page sounds like your situation, you can book a surgical assessment consultation. Its purpose is to review your situation and the possible options; any operation is then decided collectively by the multidisciplinary team, with you.

Your request is received by the Centre’s appointments team, who will organise the next steps with you. You do not need to check for yourself whether you meet the criteria.

Medical review of the French version: Dr Pierre Fournier

Scientific sources and references

Sources accessed on 12 October 2026. Reimbursement rules and information on medicines change over time.

1. Swiss Society for the Study of Morbid Obesity and Metabolic Disorders (SMOB). Directives pour le traitement chirurgical de l’obésité, in force from 1 July 2023 (in French). View source
2. Office fédéral de la santé publique (OFSP). Annexe 1 de l’ordonnance sur les prestations de l’assurance des soins (OPAS), édition du 1er juillet 2026 : chapitres 1.1 et 2.1. View source
3. Stenberg E, Dos Reis Falcão LF, O’Kane M, et al. Guidelines for perioperative care in bariatric surgery: Enhanced Recovery After Surgery (ERAS) Society recommendations, a 2021 update. World J Surg. 2022;46(4):729-751. View source
4. Kindel TL, Wang AY, Wadhwa A, et al. Multi-society clinical practice guidance for the safe use of glucagon-like peptide-1 receptor agonists in the perioperative period. Surg Endosc. 2025;39(1):180-183. View source