Bart Decadt

Consultant Laparoscopic Bariatric

& Upper GI Surgeon


When you are considering surgery, its really important to have as much information as you can to make an informed choice. Your health and the choices you make are really important to us, so we have complied a list of the most commonly asked questions for you to read, to help put your mind at ease as much as possible. All the information below has come from questions our patients have asked us, so that you too can gain the benefit of our knowledge and procedures. If you require more information, please email us.

What does the evaluation for obesity surgery involve?

As part of our preoperative assessment you will see the bariatric nurse and dietitian. Accurate preoperative assessment of your knowledge about nutrition, personal habits, and commitment to change are essential for a successful long-term outcome. You will be called to the outpatient preoperative assessment unit a few days/weeks before the planned operation and will receive general medical evaluation. This will include some blood tests and where indicated an ECG and a chest X-ray.


If you have breathing problems, or if we are concerned that you may be suffering with some degree of obstructive sleep apnoea (OSA) we might need to consider the need for a sleep study. If the test shows severe OSA, you will need to have CPAP machine to help you with breathing for a few weeks in order to reduce strain on your heart and to make the surgery safer for your body to tolerate. We will need to keep you on the High Dependency Unit overnight after surgery for closer monitoring. If you suffer with angina or have had a heart attack in the past, we will need to consider an opinion from a cardiologist and a test to investigate and if necessary treat any significant narrowing of the coronary arteries that supply the heart in order to reduce the risk to your heart.


If we feel necessary, we may recommend that you see a psychologist to make sure that an operation would be advisable and that you are mentally and emotionally prepared for the restriction on the amount of food that you will be able to at after the operation. We may also recommend that you see an endocrine doctor if we are concerned that you may have an endocrine illness causing the obesity and possibly the diabetes and requiring treatment with medications.

Who is suitable for weight loss surgery?

When appropriate non-surgical measures have been tried but failed to achieve or maintain adequate, clinically beneficial weight loss in patients whose BMI is 40 kg/m2 or more or between 35-40 kg/m2 in association with other significant disease (for example, type 2 diabetes, heart disease or high blood pressure). It is also recommended as a first-line option (instead of lifestyle interventions or drug treatment) for adults with a BMI of more than 50 kg/m2 in whom surgical intervention is considered appropriate (National Institute for Clinical Excellence). In March 2011, The International Diabetes Federation (IDF) recommended bariatric surgery to patients with BMI 30 kg/m2 (Asians from BMI 27.5 kg/m2) if their diabetes was poorly controlled. However, the need for surgery to aid weight loss is dependent on discussion with the bariatric team who will provide you expert and comprehensive advice.

How long is the surgery, and how long will I stay in hospital?

On average, the gastric banding procedure takes 20-30 minutes, the sleeve gastrectomy takes 25-40 minutes, while the bypass requires 60-90 minutes. Most patients begin liquids on the same day after the surgery and take liquid diet the following day. Almost all band patients are discharged home within 24 hours, while 80% of patients who have had sleeve or bypass are discharged the following day. The remainder may stay a day or two longer, especially if they’ve travelled a long distance, if they have mobility issues or if they have no support at home.

Why consider an operation if there is some risk?

Patients who are morbidly obese have a greatly increased risk of premature death from a number of causes, especially diabetes, high blood pressure, heart and lung disease, as well as cancer. Weight loss surgery has been shown to reduce the risk of death, to improve or reverse the weight-related complications, and to improve quality of life. In the large majority of people, the benefits of surgery far outweigh the risks, but that balance has to be discussed with the surgeon and possibly the anaesthetist.

How soon will I return to normal activity?

You may be able to do most light activities within few days of surgery and as you feel comfortable to do them. We advise that you avoid driving for an average of 10-14 days as you need to be off all painkillers, full mobile and able to confidently make an emergency stop before you start driving. Most people can return to an office job within 7-14 days after surgery, while those in a manual job might require up to 4 weeks. You will normally be given an appointment to be seen in clinic 4-6 weeks after the surgery to discuss your progress and to assist you with your food choices.

How much weight will I lose after the operation?

After surgery, the initial weight loss is rapid and gradually slows down with time as you approach your target weight. Weight loss after the gastric banding operation is slower than that after sleeve gastrectomy or gastric bypass, but can be increased by adjusting the band. On average, people lose 40-50% of their excess weight, 60-65% after sleeve gastrectomy and 65-75% after gastric bypass over a course of 12-18 months. Generally speaking, what one loses in the first 4-6 months, it will take another 8-12 months to lose the same amount of weight again. It is possible to lose more weight by a combination of regular exercise and additional dieting usually by reducing high calorie snack foods or fluids rather than reducing the meal size. Unlike ordinary dieting, where weight is regained very rapidly when the diet stops, weight loss after the surgery is more permanent and once lost, weight tends to stay off.


However, there are failure rates with each operation, and this means that some people don’t get to lose much weight or rarely none at all. On average, 10-30% of patients having gastric band will fail to lose much weight, while 5% of patients or less will fail after sleeve gastrectomy or gastric bypass. One has to work with the surgery in order to achieve the weight loss desired, and should look at surgery as an aid to weight loss rather than the answer. There are factors that predict poor weight loss, such as diabetes (especially when it has been long-standing and harder to treat, perhaps requiring insulin), polycystic ovary syndrome, older-age and sweet eating, as well as a very high BMI; people who have some of these factors are advised to consider operations that are more effective in achieving weight loss such as the gastric bypass or the sleeve gastrectomy.

Will I ‘overshoot’ and get too thin?

This is extremely rare, and when it occurs there are usually other factors that are contributing and should be addressed such as excess alcohol intake with associated alcohol-related liver disease and occasionally psychological issues that result in anorexia (severe lack of interest in food).

Is the operation reversible?

The gastric band is easily reversible as the band could be removed by keyhole surgery, and this may rarely be required if there are complications related to the band such as band erosion, pouch dilatation, band slippage, severe reflux or band infection. It is technically possible to reverse the gastric bypass, and this could be accomplished laparoscopically (keyhole surgery), though it is extremely rare to need to do that. The sleeve gastrectomy cannot be reversed as some 75% of the stomach is actually removed; however, someone could potentially reverse the effect of surgery if he/she stretches the stomach over time and increase their portion size and calorie intake.

What is the follow-up after the operation?

Our team that includes the surgeon, the dietician and the bariatric nurse will see you at regular intervals after the surgery within a structured follow-up program, and for up to two years as minimum. This often involves reviews at 6 weeks, 3 months, and then 6-monthly, but more often if necessary and particularly so after the gastric band in order to perform band adjustments and achieve an optimal degree of restriction. Surgery is but one piece of your lifetime commitment to weight control and altered habits. Psychological counseling are available after surgery as needed.

Will I need blood tests after the surgery?

If you had a sleeve gastrectomy, a gastric bypass or a duodenal switch, you will need to have regular blood tests to check on various minerals and vitamins and to ensure all is in order and that you are not anaemic. We will do these blood tests during the initial 12 months after surgery, and then we ask your GP to check these every year. You should also continue to take the recommended supplements.

Will I need to have my gallbladder removed?

Obesity as well as weight loss by any means (including diet) promotes the formation of gallstones. If you are known to have gallstones before your operation, then it is our preference to remove the gallbladder at the time of the gastric bypass or sleeve gastrectomy, but prefer not to do so at the time of gastric banding least the band might get infected. If, on the other hand, you are not known to have gallstones, then there is a 10-15% chance that you will develop gallstones after weight loss surgery and this will require a keyhole operation to remove the gallbladder.

I am a diabetic; should I continue to take my diabetes medicine?

It is not uncommon for diabetic patients, particularly those who have had diabetes for five years or less and who were taking tablets rather than insulin to control their diabetes, to find that they no longer need treatment for their diabetes (this is called “remission of diabetes”). This happens gradually as the extra weight comes off. The chance of remission of diabetes is approximately 40-50% with the gastric band, 60-65% with the sleeve gastrectomy and 80-85% with the gastric bypass. In fact, it is common that we halve the dose of insulin or discontinue it and stop metformin and/or other tablets immediately after gastric bypass surgery. It is important therefore for you to see your doctor regularly during the first 12-18 months after the operation to check your blood sugar. Your doctor will then decide whether the dose of your diabetes medicine should be reduced. This is important as your blood sugar may otherwise drop quite low (hypoglycaemia), which can be dangerous.

Will I need plastic surgery?

A variety of factors including your starting weight, weight loss that you have achieved after surgery, location of excess weight and your age influence the need for plastic surgery. In general, skin elasticity is greater in younger patients and the need for plastic surgery is less. You may need an operation to remove what might become a very saggy abdominal skin (apronectomy) after your weight has leveled. This is usually two years after surgery. Some might also require arm and thigh lifts and cosmetic breast surgery.

Can I become pregnant after bariatric surgery?

Yes. Thousands of women have become pregnant after bariatric surgery. We recommend that women of the childbearing age should practice contraception during the initial 12 months after surgery and preferably for up to 18 months until the weight loss has leveled, particularly if they have had a gastric bypass or a sleeve gastrectomy. This is because of concern for the nutrition and growth of the baby if the mother is still losing weight during pregnancy. This advice is also applicable to women who are infertile due to polycystic ovary syndrome; we have had a number of such women who didn’t follow advice and became pregnant within 3-6 months of gastric bypass surgery, though fortunately they had normal babies. We recommend that pregnant women who have had a gastric bypass should take one Pregnacare and one Pregnacare plus every day during pregnancy and should stop the iron tablets during the initial three months of the pregnancy. Women who have had a gastric band should have it fully deflated during pregnancy.

Contact Private Secretary (Barbara Dawson)  

Telephone  0161 440 9997   Fax 0161 440 8818   Mobile 07802 445558



All Enquiries

0161 440 9997

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