Gastric Sleeve vs Gastric Bypass vs SADI-S

Gastric Sleeve Vs Gastric Bypass Vs SADI

Which Bariatric Surgery Is Right for You in Ireland, UK & Northern Ireland?

Choosing bariatric surgery is not simply about losing weight. It is about improving health, reducing long-term medical risk and selecting the right procedure for your BMI, metabolic condition and overall health profile.

Patients across Ireland, the UK and Northern Ireland often compare three main procedures:

Each operation works differently. Understanding those differences is essential before making a decision.

Understanding the Three Procedures

Gastric Sleeve (Sleeve Gastrectomy)

Gastric sleeve surgery involves removing approximately 70–80% of the stomach. The remaining stomach becomes a narrow tube.

It works by:

  • Restricting food intake
  • Reducing hunger hormones
  • Promoting early fullness

It does not involve bypassing the intestine.

Sleeve surgery is commonly offered to patients with BMI 35–45 and can deliver strong, sustainable weight loss when appropriately selected.

Gastric Bypass (Roux-en-Y)

Gastric bypass creates a small stomach pouch and reroutes part of the small intestine.

It works through:

  • Restriction
  • Hormonal changes
  • Reduced calorie absorption

It has a strong metabolic effect and is particularly effective in patients with type 2 diabetes.

Gastric bypass is suitable for BMI 35–55 and can also be appropriate in higher BMI patients depending on clinical circumstances.

SADI-S (Single Anastomosis Duodeno-Ileal Bypass with Sleeve)

SADI-S combines a sleeve gastrectomy with a longer intestinal bypass.

It provides:

  • Restriction
  • Powerful hormonal change
  • Greater metabolic impact

It is particularly effective for:

  • BMI 45–70+
  • Severe type 2 diabetes
  • High BMI patients requiring stronger long-term weight loss

SADI-S is technically more advanced and should be performed in experienced centres.

Clear Comparison: Sleeve vs Bypass vs SADI-S

Feature Gastric Sleeve Gastric Bypass SADI-S
Type  Restrictive Restrictive + Metabolic Restrictive + Strong Metabolic
Typical BMI Range 35–50 35–55 45–70+
Suitable for BMI 60+ Sometimes Yes Highly Suitable
Diabetes Improvement Moderate High Very High
Weight Loss Strength Strong Stronger Strongest (High BMI)
Long-Term Maintenance Good Very Good Excellent in Severe Obesity
Technical Complexity Moderate Higher Advanced
Ideal Candidate Moderate obesity Obesity + diabetes Severe obesity / BMI 50+

 

Which Procedure Is Best for Higher BMI?

For patients with a BMI over 50, the strength, durability and metabolic impact of weight loss become especially important.

While gastric sleeve can be effective in selected patients, it may not provide sufficient long-term weight loss for individuals with BMI 60 and above.

Gastric bypass offers significant weight reduction and strong diabetes improvement, and remains an excellent option for many patients with severe obesity.

However, for patients with BMI 50–70+, SADI-S is often considered the most effective bariatric procedure due to its powerful metabolic effect and greater long-term weight loss potential. In experienced hands, it provides stronger hormonal changes and sustained results in patients with high BMI.

That said, the most appropriate procedure always depends on individual factors such as overall health, diabetes severity, previous surgeries and surgical risk profile. A personalised consultation is essential to determine which operation is safest and most effective for you.

Safety and Complexity

All bariatric procedures are safe when performed in experienced centres.

However, high BMI and complex cases require:

  • Careful pre-operative optimisation
  • Experienced anaesthetic management
  • Technical precision
  • Structured long-term follow-up

The surgeon’s experience is often more important than the name of the procedure itself.

Long-Term Outcomes

Long-term success is influenced by:

  • Procedure selection
  • Multidisciplinary support
  • Nutritional follow-up
  • Patient engagement

For some patients, sleeve is entirely appropriate. For others, especially those with higher BMI or complex metabolic disease, bypass or SADI-S may provide more durable results.

There is no single “best” operation for everyone.

Why Personalised Assessment Matters

Bariatric surgery is not a menu choice. It is a clinical decision.

The safest and most effective approach is to consult an experienced bariatric surgeon who understands:

  • BMI-specific risks
  • Metabolic disease
  • Revision options
  • Long-term nutritional management
  • Robotic and advanced surgical techniques

An experienced surgeon can evaluate your individual profile and recommend the procedure most suited to your long-term health.

Expertise at Blackrock WeightCare

At Blackrock WeightCare, procedure selection is always personalised. Our team includes experienced surgeons, specialist nurses, dietitians and anaesthetists who guide patients carefully through the decision-making process.

Mr William Robb is one of the highest volume robotic surgeons in Europe and has performed more than 1,500 robotic surgical operations. His experience in complex and high BMI cases allows for careful selection of the most appropriate procedure, particularly where advanced techniques such as robotic SADI-S are considered.

Patients from Ireland, the UK and Northern Ireland seek specialist assessment not simply for surgery, but for clarity, safety and long-term results.

Choosing between sleeve, bypass, and SADI-S is not about selecting the most popular option. It is about choosing the right operation for you, guided by experience and evidence.

If you would like a personalised consultation to understand which procedure may suit you best, fill out an inquiry form here or call 01 255 2479.

Your Health. We Care.

Emer O’Driscoll

Senior Dietitian

Emer O’Driscoll holds an MSc in Nutrition and Dietetics from the University of Ulster, Coleraine (2014). Emer has experience in clinical and outpatient settings, in particular, her passions are intuitive eating, counselling, and weight management. Emer is actively involved in the support of patients before and after weight loss surgery. She recognises the importance of consistent follow-up care with a dietitian through your pre and post-surgical journey. 

She holds a certificate in Motivational Interviewing from the National Institute for Preventive Cardiology (NIPC) and is a Certified Intuitive Eating counsellor. Emer developed and leads the SUCCEED Programme. She is a member of the Irish Nutrition & Dietetic Institute (INDI) and a CORU registered dietitian.

David Johnston

Senior Dietitian

David Johnston is a Senior Dietitian at Blackrock WeightCare. He holds a BSc in Human Nutrition and Dietetics from Trinity College Dublin and TU Dublin, and has completed additional training in behaviour change skills and the delivery of evidence-based obesity management.

David has worked in rehabilitation and integrated care services in both Ireland and Australia, supporting patients living with obesity, diabetes and other long-term health conditions. Chronic disease management has been a key area of interest throughout his career, and he understands the importance of a multidisciplinary approach when supporting people with obesity.

As part of the Blackrock WeightCare team, David provides education and follow-up care for patients before and after surgery. He helps patients prepare for surgery, supports them as they adjust to changes in eating and drinking afterwards, and works with them to build sustainable habits that support long-term health and weight management.

David is a CORU registered dietitian and a member of the Irish Nutrition and Dietetic Institute (INDI). His approach is practical and patient-centred, with a focus on helping patients better understand their nutrition and managing it in a way that works for them.

Niamh Forster

Senior Dietitian

Niamh Forster is a Senior Dietitian at Blackrock WeightCare, with 6 years of experience working with people living with obesity and supporting them with practical nutrition and lifestyle advice. She has worked in both clinical and outpatient settings, including weight management, and has a particular interest in supporting patients before and after bariatric surgery.

Niamh holds a BSc in Human Nutrition and an MSc in Clinical Nutrition and Dietetics from University College Dublin, completed in 2020. She has also completed further training in Behaviour Change, Intuitive Eating Counselling and Nutrition for PCOS.

She is a CORU registered dietitian and a member of the Irish Nutrition and Dietetic Institute (INDI).

As part of the Blackrock WeightCare team, Niamh supports patients in making sense of the dietary changes that come with bariatric surgery and helps them build habits that are realistic, manageable and suited to everyday life. Her approach is practical, evidence-based and centred around the individual, with a strong focus on supporting patients in a way that feels steady, respectful and achievable.

Nikki O’Toole

Bariatric CNS

Nikki O’Toole is a Bariatric Candidate CNS at Blackrock WeightCare, with over 18 years of nursing experience and a strong background in surgical nursing. She has worked in Blackrock Clinic for more than 10 years, caring for bariatric patients at ward level and now supporting patients throughout their journey before and after surgery.

Nikki holds a BSc Degree in Nursing and has recently completed a course in An Integrated Approach to Cardiometabolic Chronic Disease. In her role, Nikki provides education, preparation and ongoing support to patients at each stage of their journey. She helps patients feel informed and ready for surgery, and continues to support them after their procedure, both during their hospital stay and long after they go home. She understands how important it is for patients to feel reassured and know that support is always there when they need it.

Nikki gets great fulfilment in being part of transformation for patients and their families. She is committed to helping each patient feel cared for and confident throughout their time with Blackrock WeightCare.

Susan Healy

Bariatric CNS

Susan Healy is a Bariatric Clinical Nurse Specialist (CNS) at Blackrock WeightCare, with more than 20 years of nursing experience and a long-standing specialist interest in bariatric care. She first began working with bariatric patients in Australia almost 19 years ago and has been caring for bariatric patients in Blackrock Clinic for the past 10 years. She became a Bariatric CNS in June 2024.

Susan holds a BSc Degree in Nursing and is a Registered Nurse (RN) and Certified Bariatric Nurse (CBN) through the American Society for Metabolic and Bariatric Surgery (ASMBS). She is also a member of BOMSS, the British Obesity and Metabolic Surgery Society.

In her role, Susan supports patients right through their bariatric journey, both physically and emotionally, with a strong focus on education, reassurance and ongoing care. She is a steady point of contact before and after surgery, helping patients feel informed, prepared and well supported. Susan is passionate about providing patient-centred care and believes that people should be met with compassion and respect at all times. She takes great satisfaction in seeing the positive difference bariatric surgery can make and is committed to making sure each person feels listened to and supported throughout their journey.

Dr Matilde Mijares Zamuner

Consultant Endocrinologist and Diabetologist

Dr Matilde Mijares Zamuner is a Consultant Endocrinologist and Diabetologist at Blackrock WeightCare, with a particular interest in obesity, diabetes and the medical management of weight-related conditions. She graduated from medical school at the Central University of Venezuela in Caracas and completed her Higher Specialist Training in Endocrinology, Diabetes and Nutrition at Alicante University Hospital in Spain in 2013. She also completed a Master’s Degree in Clinical Research in Spain.

During her specialist training in Spain, she gained extensive experience in the management of metabolic conditions, including obesity and related conditions such as type 2 diabetes, high blood pressure and high cholesterol. She moved to Ireland in 2014 and completed a research fellowship in diabetes at the Mater Misericordiae University Hospital. 

As part of the Blackrock WeightCare team, Dr Mijares Zamuner supports patients by assessing hormonal, metabolic and nutritional factors that may be contributing to weight gain, including conditions such as PCOS and thyroid disease. She also works closely with patients before and after bariatric surgery and is involved in the medical treatment of obesity, including prescribed medication where appropriate.

Dr Mijares Zamuner is a member of the Irish Endocrine Society, the Spanish Endocrine and Diabetes Society, the European Society of Endocrinology and the Royal College of Physicians of Ireland. Her approach is centred on helping patients understand obesity as a chronic disease and supporting them in a clear and compassionate way to improve their long-term health and quality of life.

Achille Mastrosimone

Consultant Upper Gastrointestinal Surgeon and Bariatric Endoscopist

Achille Mastrosimone is a Consultant General and Upper Gastrointestinal Surgeon with a specialist interest in upper gastrointestinal surgery, diagnostic and therapeutic endoscopy, and bariatric and metabolic surgery. He works across Connolly Hospital, Hermitage Clinic and Blackrock Clinic, and is also an Honorary Clinical Senior Lecturer at RCSI University of Medicine and Health Sciences.

He holds an MD, a PhD in Clinical and Molecular Oncology, a Professional Diploma in Clinical Leadership from RCSI, and a Master in Bariatric and Metabolic Surgery from Gemelli Hospital, Rome.

As part of the Blackrock WeightCare team, he supports patients through pre-operative endoscopic assessment and post-operative endoscopic follow-up. 

Excitingly, Achille also brings expertise in endobariatric procedures, including TORe (Transoral Outlet Reduction), to help manage post-bypass weight regain and dumping syndrome.

Achille is registered on the Irish Medical Council Specialist Register in General Surgery and is a member of IFSO (International Federation for the Surgery of Obesity and Metabolic Disorders), ESGE (European Society of Gastrointestinal Endoscopy), ISDE (International Society for Diseases of the Esophagus) and EAES (European Association for Endoscopic Surgery).

His approach is centred on giving patients clear, compassionate and personalised support, helping them feel informed, reassured and well cared for before and after endoscopy.

Dr Finian Fallon

Psychologist

Dr Finian Fallon provides psychological support and assessments for patients seeking bariatric surgery at Blackrock WeightCare. He works closely with bariatric teams in Ireland and has a strong interest in supporting patients as they prepare for surgery and adjust to the changes that come with it.

Finian has contributed to research and published work in the area of obesity, and was previously a Research Fellow at St Vincent’s University Hospital, where he provided group support for people living with obesity. He has also worked as Dean of Psychology at a private college in Dublin, where he developed education programmes in areas including CBT, addiction and traumatology.

His academic work has included External Examinerships and supporting PhD students in their development. He has also presented at the SCOPE School on Obesity, an internationally recognised training programme in obesity led by experts in the field.

Finian has a particular interest in the psychological impact of obesity, including the effect of stigma and self-stigma on people’s lives. He is also very aware of the role trauma can play for some patients living with obesity. His research includes a widely reported study on trauma and wellbeing among more than 2,000 members of An Garda Síochána.

His approach is thoughtful, respectful and compassionate, with a strong focus on helping patients feel understood, supported and well prepared throughout their journey.

Professor John McDermott

Consultant Endocrinologist

Professor John McDermott is Consultant Endocrinologist at the Hermitage Medical Clinic. Working closely with Mr Robb and the team at Blackrock WeightCare, he supports patients through their weight loss journey with a focus on metabolic health, endocrine assessment and long-term aftercare. He plays an important role in guiding patients before and after bariatric surgery, and supporting them as they adjust to the hormonal, metabolic and lifestyle changes that follow treatment.

Professor McDermott graduated from the University of Galway with first-class honours and the gold medal for first place in medicine. Following his specialist training, he was appointed as a Consultant Endocrinologist in 2007. He has extensive experience in endocrinology, diabetes and general internal medicine, and a strong commitment to clinical research and medical education.

Dr Conor Woods

Endocrinologist & Bariatric Physician

Dr Conor Woods is an Endocrinologist and Bariatric Physician at Blackrock WeightCare, with specialist interests in obesity medicine, endocrinology and diabetes. He completed his undergraduate medical training at RCSI and his Higher Specialist Training in Endocrinology in Ireland. He also holds a PhD from UCD in steroid metabolism and obesity, and completed a fellowship in Oxford.

Dr Woods supports patients with the medical assessment and management of obesity and related metabolic conditions. As part of the multidisciplinary team, he helps ensure patients are well informed, appropriately assessed and supported throughout their care.

Barkha Jain

Digital Marketing Manager and Web Developer

Barkha Jain is the Digital Marketing Manager at Blackrock WeightCare, with over 20 years of experience in advertising, marketing and business development. She holds a Bachelor’s degree in Journalism and Mass Communication from DAVV University, India, and a Master’s degree in Digital Marketing from UCD, Ireland.

For the past 10 years, she has specialised in healthcare marketing, working with surgeons across bariatric surgery, plastic surgery, respiratory medicine, IVF and orthopaedics. Before moving to Ireland, she founded a digital marketing agency in India in 2016 and worked with healthcare clients across the country, including spending 8 years with Mohak Bariatrics, an internationally renowned bariatric service in Indore, India. Barkha has facilitated a collaboration between Mohak Bariatrics and Blackrock WeightCare – a connection we are proud to have established.

Her work is rooted in a genuine belief that healthcare communication should do more than promote services. It should bring clarity, build trust and help people make informed decisions for their health and wellbeing.

Susan Anderson

Patient Co-Ordinator

Susan Anderson is a Patient Co-Ordinator at Blackrock WeightCare and is often the first point of contact for patients enquiring about weight loss surgery. Susan speaks with patients by phone to guide them through the process, answer their questions and provide clear information about the process from first appointment, assessment for surgery and our dedicated follow up program of care. She follows up with detailed information on the next steps, helping patients feel informed from the outset.

Susan also attends clinics and values meeting patients in person, offering support as they move through different stages of treatment. She understands that reaching out about bariatric surgery can feel like a big step and how important it is for patients to be given time, information and reassurance to make the decision that is right for them.

With almost two decades of experience working in a hospital setting, Susan is committed to helping each patient feel comfortable, informed and well supported from their first contact with Blackrock WeightCare.

Lucy O’Shea

Patient Co-Ordinator

Lucy O’Shea is a Patient Co-Ordinator at Blackrock WeightCare, where she supports patients throughout all phases of their treatment – from bariatric surgery, to medical follow up with optimisation of health and weight and then also co-ordinating body contouring surgery for those patients who require this final phase.

Lucy helps guide patients through each stage of the process, from explaining what to expect and preparing them for consultations to providing support before and after surgery.

Working closely with the clinical team, Lucy ensures that patients feel informed, supported and reassured throughout their journey to better health. She understands that this can be a significant step, and Lucy is committed to making the experience as comfortable and straightforward as possible.

Lucy helps each patient feel heard, supported and at ease throughout their care with Blackrock WeightCare.

Maria Cray

Practice Manager

Maria Cray is the Practice Manager at Blackrock WeightCare, with over 20 years of experience managing busy private surgical clinics. Before joining the team, she spent two decades as Practice Manager for a consultant eye surgeon, where she ran a successful multi-staff practice and supported patients through every stage of their care.

She brings a calm, organised and caring approach to the role, with a great understanding of what patients need from specialist care. From coordinating appointments and referrals to helping manage surgical schedules, Maria plays a central role in ensuring that every patient’s experience is as smooth as possible.

WIth the whole team, Maria creates a welcoming and professional environment where patients feel supported, informed and genuinely cared for throughout their journey with Blackrock WeightCare.

Go Surgical Limited
Suite 9, Blackrock Clinic, Rock Road, Blackrock, Dublin, A94 E4X7