This has not been a problem with any of our patients. The operation has been designed to reduce the calorie intake to a level which is adequate to nourish the patient at their correct body weight. The weight will fall until this point is reached, and will then stabilise.

The main reason that we adopted the gastric procedure as our chosen operation is the excellent long term results. Even after more than 10 years, patients keep the excess weight off. In Leeds, we have seen no cases of worrying weight gain after the operation. Once the weight loss period of up to two years is over, it is quite common for weight to vary, but substantial weight gain has not been a problem. Scientific data from the USA over a period of 15 years confirms this.

Initially, food must be pureed since there will inevitably be some swelling around the internal stitching and stapling. Solid food is started again step by step and after a period of between two weeks and three months, patients are back on normal solid food. However, the amount of food eaten will be much smaller, and this must continue permanently.

It is technically possible to reverse the operation surgically, but no patient has ever asked us to do this. Neither have we ever had to reverse the procedure on medical grounds.

The gastric bypass operation is major surgery, but has been shown to be safe and well tolerated. The major risks related to any surgery in the very overweight are the chance of chest infection, infection of the wound and wound hernias later on. We see these in about 10% of our patients and wound hernias generally require surgical repair. Chest infections and blockages in the veins of the lower legs are a potential concern but we take various special precautions to prevent them, and these complications have not been a problem.

The greatest hazard is of a leak from the new, stapled join between the stomach and the intestine. We X-ray all of our patients after the procedure to make sure that there is no leak. We have had no leaks in all the procedures we have carried out to date. If it did occur, the patient would need an urgent second operation.

Out of the first 350 procedures we carried out, we had to remove the spleen of one patient because it was damaged during the operation. This led to no long-term problems.

Up to December 2000 we had completed 350 gastric bypass procedures, with one patient dying due to respiratory failure some time after the operation. He suffered a degree of respiratory failure before the operation, and the procedure was performed to improved his breathing long-term.