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Operations for Obesity

Surgeons often define success after obesity surgery as a loss of over 50 per cent of excess weight. Most people after surgery will end up much closer to their ideal weight as predicted by the BMI chart but will still carry some excess weight and loose skin.

Obesity surgery modifies the anatomy of the gastrointestinal tract. There are a number of surgical approaches that work by either reducing or restricting food intake (restrictive) and/or by reducing the absorption of food (metabolic).

The two surgical principles leading to weight loss


The main surgical techniques are

Combination of metabolic and restrictive obesity surgery

  • Gastric bypass
  • Sleeve gastrectomy

Restrictive only obesity surgery

  • Gastric banding

Each technique has its advantages and disadvantages, and a patient’s needs and risk factors may dictate a particular approach.

The operations reduce appetite and the amount that can be eaten. Eating is a soothing, enjoyable activity that everyone uses as a way of coping with stress and/or socialising with others. Obesity surgery changes this permanently and the realisation that this coping mechanism may be removed can be a daunting prospect for anyone considering surgery.

Changing how you eat, how you exercise and how you deal with stress is vital to getting the best result from obesity surgery. A weight loss operation does not do it all for you; it is best seen as a tool that makes achieving this lifestyle change possible. The obligation is on each patient to make the best use of this tool.

Surgical options for obesity are explained in detail in our patient information booklet

Gastric bypass surgery requires you to make significant changes to your lifestyle for the rest of your life.