Bariatric Surgery: Sleeve Gastrectomy or Gastric Bypass? Who Is Eligible?

The most common question asked by people considering bariatric surgery is whether sleeve gastrectomy or gastric bypass is better. Both are effective operations. The important question is not which operation is universally superior, but which is most suitable for the individual patient.

Who may be suitable for bariatric surgery?

Surgery is considered for people who meet recognised clinical criteria, particularly those with a body mass index (BMI) of 40 kg/m² or above, or a BMI of 35 kg/m² or above with obesity-related conditions such as type 2 diabetes, hypertension or sleep apnoea. Patients should also have made appropriate non-surgical attempts and be ready to follow long-term dietary and lifestyle guidance.

Sleeve gastrectomy

During sleeve gastrectomy, approximately 75–80% of the stomach is removed, leaving a narrow tube-shaped stomach. This reduces meal capacity and also affects hormones involved in hunger.

• The intestinal route is unchanged.
• The risk of nutrient malabsorption is generally lower than after bypass.
• The operation is usually shorter.

However, sleeve gastrectomy may worsen significant reflux, so it may not be the preferred choice for patients with severe reflux disease.

Roux-en-Y gastric bypass

Gastric bypass creates a small stomach pouch and connects it to a later part of the small bowel. It limits intake and changes absorption and metabolic signalling. It can be particularly effective for type 2 diabetes and reflux.

• It has a strong metabolic effect on type 2 diabetes.
• It generally improves reflux symptoms.
• It provides effective long-term weight control.

Because absorption changes, lifelong vitamin and mineral supplementation and regular blood tests are essential.

How is the procedure selected?

Bypass may be favoured in severe reflux or poorly controlled type 2 diabetes. Sleeve gastrectomy may suit patients who prefer a simpler anatomical procedure and have no important reflux. These are guiding principles rather than a prescription; the final decision follows examination and investigation.

Life after surgery

Success depends on long-term follow-up. Patients move gradually from liquids to puréed and then solid food, prioritise protein, remain physically active, take prescribed supplements and attend regular reviews.

Sleeve gastrectomy and gastric bypass are not rivals. They are different tools for different patients.