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Common gastric bypass questions

The following are some of the most commonly asked questions in relation to gastric bypass.


How much weight can I expect to lose?


On average we expect gastric bypass patients to lose 60-70% of their excess weight.   Obviously some people will do better and some not as well as this. 


Can gastric bypass always be done with “keyhole” surgery?

No.  In some cases of extreme obesity it may actually be less risky to perform surgery through as a standard “open” procedure.  However, in most cases gastric bypass can be done as a laparoscopic (keyhole) intervention.


Will I lose more weight with gastric bypass than with a gastric band?

Not necessarily.  Although initial weight loss with the gastric bypass tends to be greater, some recent studies show that after 3-5 years, there is actually very little difference between the excess weight lost following gastric banding and gastric bypass.  A major factor is the level of post-operative support available to the patient undergoing gastric banding.  Some surgeons prefer to perform gastric bypass simply because they are unable to provide the level of behavioural and lifestyle support which is essential in the follow-up of gastric band patients.  Hence the selection of one procedure rather than another is to a large extent a function of patient choice and surgeon preference, rather than any hard evidence that one procedure is more effective than another.   Because there is no reliable way of predicting which patient will succeed with which procedure, in the end it comes down to the preference of the patient and the surgeon.  Nevertheless, given that patient safety is the first consideration it must always be borne in mind that laparoscopic banding is a very much less risky surgical option than gastric bypass.   


Is gastric bypass an effective procedure?


Yes.  Gastric bypass remains one of the most effective surgical treatments for obesity, with an excess weight loss of 60-70% in the best centres.


What does my BMI need to be to be considered for gastric bypass?


We will normally consider patients with a BMI of 30 kg/m2 or more for laparoscopic gastric banding. [To calculate your Body Mass Index go to www.healthierweight.co.uk)


However, given that the risks for gastric bypass are considerably higher than for gastric banding, we usually require that the bypass candidate should have a BMI of 40 kg/m2 or more.  Nevertheless, each case is different and has to be considered taking into account the pattern of weight gain, the presence of co-morbidities such as diabetes, hypertension etc.  


Will I only be able to eat tiny amounts for the rest of my life? Will I be able to eat regular food?


At the beginning you will likely only eat approximately two to four tablespoons of food. You will gradually advance your diet and by around eight weeks you should be eating "regular" food. Your capacity will increase over the first six to nine months of surgery. The stomach pouch and small intestine learn how to work together over a period of months. Many patients notice a dramatic increase in the amount of food they can handle comfortably. This is normal in most cases. This is the time when the good habits developed in the first few months will support further weight loss.



Do I have to take vitamin and mineral supplements for the rest of my life?

Yes.  Because gastric bypass limits absorption of calories, it can also limit the absorption of essential vitamins and minerals.  This is why daily vitamin and mineral supplementation is essential to your long-term health following gastric bypass. 


What about blood tests?

To ensure that you are maintaining the necessary levels of essential vitamins and minerals, you will need to have regular blood tests for the rest of your life.  In the Healthier Weight package, your first blood checks will be carried out at 6 months and then 12 months.  Depending on the results, the doctor will then be able to advise you on future testing frequency. 


What is “dumping syndrome”

Dumping syndrome is a group of signs and symptoms that develops most often in people who have had surgery to remove all or part of their stomach, or in whom much of their stomach has been surgically bypassed to help lose weight. It may occur early or late. 


Early dumping - (rapid gastric emptying) typically starts during a meal or within 15-30 minutes following a meal.  It is caused by foods which are high in sugar passing too quickly from the stomach pouch into the small intestine.  Because the food is very concentrated (dense) it attracts a correspondingly large amount of fluid into the gut causing it to become stretched and painful.  Symptoms include:

  • Nausea

  • Vomiting

  • Abdominal pain, cramps

  • Diarrhea

  • Dizziness, lightheadedness

  • Bloating, belching

  • Fatigue

  • Heart palpitations, rapid heart rate


Late dumping (rapid gastric emptying) typically occurs 1-3 hours after eating. Late dumping is caused by marked fluctuations in blood glucose levels among patients whose digestive anatomy has been altered by surgery, like gastric bypass. When sugar is eaten it is quickly absorbed into the bloodstream triggering a rapid rise in blood sugar levels. The pancreas responds by secreting an equally large amount of insulin to soak up the excess blood sugar.  However, sometimes the pancreas produces too much insulin, resulting in a low blood sugar level (hypoglycaemia).  Symptoms of late dumping include:

  • Sweating

  • Weakness, fatigue

  • Dizziness, light-headedness

  • Shakiness

  • Feelings of anxiety, nervousness

  • Heart palpitations, rapid heart rate

  • Fainting

  • Mental confusion


There are specific nutritional and behavioural strategies that can help to mitigate the effects of dumping syndrome.


Will I lose all my hair? How do I keep it from falling out?

While not all patients lose some hair after the bypass, many do. The reason has to do with weight loss and not surgery. Anyone who experiences a rapid, sustained weight loss will frequently also experience some temporary hair loss as well. This usually occurs between the fourth and the eighth month after surgery. You can help by maintaining a high protein diet, keeping well hydrated and taking your daily vitamin and mineral prescription (especially zinc).  You may also find kelp (a seaweed extract available from health food shops) helpful.  Almost all patients will experience natural hair re-growth after the initial period of loss. 


Can I get pregnant after weight loss surgery?

When a woman of child-bearing age undergoes gastric bypass surgery, one of the first things she will hear from the nay-sayers is that after surgery she cannot have a healthy pregnancy because of presumed nutritional deficiencies. The contrary is true. Morbid obesity results in a high rate of complicated pregnancies and a high rate of miscarriage. Women who become pregnant after achieving weight loss with gastric bypass generally have lower risk pregnancies than morbidly obese women.


So if you are a woman of child-bearing age and in otherwise good health, you should be able to have a baby after this surgery - but not right away. If you were to become pregnant in the first 12 months following this surgery, it could harm your health and that of a developing fetus. It is strongly recommended that women wait at least one year after the surgery before a pregnancy. Approximately one year post-operatively, your body will be fairly stable (from a weight and nutrition standpoint) and you should be able to carry a normally nourished fetus. You should consult your weight-loss specialist as you plan for pregnancy.


Women who need to take contraceptive precautions are all women who have not yet gone through menopause, as well as women who have completed menopause within the last two years. This applies even if you have not had regular periods, or if you believe that you are not capable of becoming pregnant.

Unfortunately, it is best to avoid birth control pills during the month before surgery, and for at least two months after surgery because they increase the risk of blood clots. Please be sure to talk with your family doctor or gynaecologist about a birth control method that will be best for you.


Can I still take all my medications after the bypass?

Food passing out of your new stomach pouch must squeeze through a new small opening before it gets into the normal digestive tract. This hole, or stoma, will dictate what size medications can pass through to your digestive system. Pills or capsules that are small enough will pass through the stoma without a problem.  But to be safe, you may want to crush all your medications or find liquid substitutes for them.  Not all pills can be crushed (e.g., time release) and some taste too awful to be tolerated in a crushed form.  Speak to your doctor about which of your medications can be taken in liquid form and which can be crushed.


Are there any medications that I must avoid altogether?

Some medications are not to be used because they may cause ulcers or inflammation in your stomach pouch.  You should permanently avoid using any type of non-steroidal anti-inflammatory drugs also known as “NSAIDs”, which include pain relievers such as aspirin, Brufen, Diclofenac, Sulindac, Celecoxib, Diflunisal,  Naproxen, Piroxicam etc.  If you are unsure, ask the Healthier Weight for advice.


How long does it take to recover from gastric bypass?

It takes 4-6 weeks to recover from the immediate physical effects of gastric bypass surgery, though there is considerable individual variation.   However, it is by no means uncommon for patients to report fatigue, feeling tearful and generally “down” for several months afterwards.  This is a common feature of any major surgical procedure and is not specifically a reflection of the gastric bypass patient. 

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The information within this guide to obesity / weight loss surgery uk is provided by Healthier Weight. Intuition Communication Ltd bears no responsibility for information published in this guide. Read Disclaimer in full.