Landmark gastric bypass trial presented to policymakers at Evidence Week
- 17 November 2025
The By-Band-Sleeve trial, which recently found gastric bypass is the most clinically and cost-effective form of interventional surgery for people living with severe obesity, has been presented to policymakers at Sense About Science’s Evidence Week at Westminster. The week brings together parliamentarians and other policymakers with researchers to address big policy questions with evidence-based solutions.
NIHR Bristol BRC’s Surgical Innovation theme lead Professor Jane Blazeby, alongside Professor Barney Reeve and Anni King, made the case at the event for advising bypass for patients electing to have bariatric and metabolic surgery. Their stand featured an anatomical model showing how gastric bypass surgery works.
Their recommendations include:
- Gastric bypass: When someone requires surgery, gastric bypass should be offered first
- Further research: To compare the effectiveness of the new drugs vs gastric bypass surgery
The Bristol team presented their findings to parliamentarians including MPs Anneliese Dodds, George Freeman and Sir Bernard Jenkin, equipping them with vital information to inform the decisions they make on future guidelines for weight loss surgeries within the NHS.
Ahead of the event, the team also produced a policy brief (PDF) and video to explain their research and recommendations:
Professor Jane Blazeby said:
“Evidence week was a fabulous opportunity to share our research findings. We had to be punchy and brief – good training for an academic.”
Evidence Week, now in its eighth year, is run by the campaigning charity Sense about Science, in partnership with the Quadram Institute, the UK Statistics Authority, communities and research institutions from across the UK. During the week, MPs meet with leading scientists to get the latest insights on pressing issues covering topics as varied as Artificial Intelligence, health, sports gambling and prison management. It is an opportunity for the public, parliamentarians and researchers to come together to share knowledge and insights.
It also empowers legislators to engage with evidence and equips them with the critical tools to handle uncertainty, identify bias and scrutinise underlying assumptions.
Tracey Brown, Director of Sense about Science, said:
“MPs must engage with an astounding breadth of subjects and sources any given week. This is why Evidence Week in Parliament offers two days of rapid-fire briefings on cutting-edge tools and insights with some of the UK’s leading research groups. We’re delighted that MPs have the chance to hear directly from the University of Bristol about their new evidence on bariatric surgery that can inform NHS guidance on treatments for those living with obesity.”
Photo credit: James Gifford-Mead