By Band Sleeve Home

Welcome to the new website of the By Band Sleeve study.


July 2021 – New article from our BBS Study Dietetics Expert Mary O’Kane


About the By Band Sleeve Study:

What we know and what we don’t know about bariatric surgery

Obesity is an increasing health problem in the UK. Current national guidelines recommend that surgery is considered for people with severe and complex obesity. This surgery is known as bariatric surgery. Three of the most common types of bariatric surgery operations are: the adjustable gastric band (‘Band’), the Roux-en-Y gastric bypass (‘Bypass’), and the gastric sleeve (‘Sleeve’). At the moment, health professionals do not know which of these three operations is the most effective for long-term weight loss and improvement of health problems and quality of life.

In January 2016 the By-Band-Sleeve study was selected by the National Institute for Health Research (NIHR) as part of their BIG Challenge campaign to highlight studies which are involved in obesity-related research, from the perspective of the patient and the researchers. For more information on the study design and implementation visit here

Can I take part?

The By-Band-Sleeve study that includes patients undergoing the three different types of surgery has now completed recruitment. We are not accepting new patients for that part of the study. We do have our Metabolomics sub-study that is collecting blood samples in patients who undergo routine NHS bariatric surgery. You may be able to take part in this, however, only if you are recommended for weight loss surgery via the usual routes. Please find out more about our Metabolomics sub-study here

Study Team

Above is the By Band Sleeve study team. This photograph was taken at our annual Investigators’ Meeting in November 2019. To find out more about the study team follow these links: University of Bristol Team, Clinical Leads, University of Oxford & University of Birmingham.

Study Status

In late September 2019 the By Band Sleeve study completed recruitment. The study reached its target of 1341 patients consented and randomised. The study has since been in a follow up phase during which data on patients will continue to be collected through visits to their recruiting hospitals and via online or postal questionnaires. To find out more about follow up visit here

Covid Update – September 2020

The By Band Sleeve study was in a follow up phase during the UK lockdowns resulting from the Covid-19 pandemic. This meant that the study operations at the coordinating centre has never stopped, despite the study team moving to a working-from-home status. Contributing hospitals across the country moved to continue their follow up appointments to telephone and video clinics and the coordination team have kept in close contact with our study colleagues across the country throughout.

As of September 2020 we are starting to see a restarting of bariatric surgery across some hospitals Trusts in the UK. We are in close communication with all of the research teams in these centres to ensure that any remaining surgeries are scheduled to take place as soon as possible. We are also working hard to ensure that face-to-face visits can start again either in hospital or at patients’ homes. We are keen to ensure that this is done in a fully approved and safest way for patients. Further information and updates will be available from your local research team (link here to teams)