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Bariatric Surgery- Unstable Blood Sugar After Gastric Bypass

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Many would say the benefits of weight loss surgery are obvious.  You look better, you feel better, you’re healthier, and you live longer.  There are many common side effects of surgery, which clients obviously must decide for themselves if the potential benefits are worth the risks and inconveniences.  There is an emerging trend however of a much more serious complication of unstable blood sugar. 

Gastric Bypass

Roux en Y gastric bypass

Roux en Y gastric bypass

Bariatric Surgery Benefits and Risks

Bariatric surgery is a general term referring to weight loss surgery. Approximately 160,000 Americans have gastric bypass weight loss surgery each year. Generally candidates must be at least 100 lbs overweight, and go through rigorous testing and counseling before surgery. The most common surgery is the Roux-en-Y. Of course there are risks with any surgery, and the decision to have bariatric surgery cannot be taken lightly. The benefits must outweigh the risks. What are the benefits and risks?

A significant proportion of prospective clients already have weight-related chronic health problems such as high blood pressure, sleep apnea and diabetes. Many bariatric candidates and their physicians consider the surgery a matter of life and death. Other candidates are surely at risk to develop these and other obesity-related problems that are known to negatively impact good health and quality of life.

There are risks of complications related directly to the surgery, such as bleeding and leakage around the surgical site. There is an array of side effects after surgery, many of which are permanent. Among these are multiple vitamin and nutritional deficiencies and something called dumping syndrome. Dumping occurs when undigested food passes too quickly from the now egg-sized stomach into the small intestine. Symptoms, which can include feeling faint or dizzy, tend to happen after a high carbohydrate meal.

Dramatic Before and After Weight Loss Surgery

Dramatic Before and After Weight Loss Surgery

Sharon Osborne with husband Ozzy.  Sharon has kept her weight off after LapBand surgery, with no apparent serious side effects.

Sharon Osborne with husband Ozzy. Sharon has kept her weight off after LapBand surgery, with no apparent serious side effects.

Reactive Hypoglycemia

A condition is emerging in a small percentage of clients, occurring 2 to 5 years after bariatric surgery. The condition, associated primarily with the Roux-en-Y procedure, is a potentially dangerous drop in blood sugar, called hypoglycemia. The symptoms occur after meals and include feeling confused or lightheaded, having a fast pulse, sweating, and shaking. Because these symptoms are similar to dumping symptoms, many clients are not given a proper workup for blood sugar regulation abnormalities. One factor that distinguishes hypoglycemia in these clients is blacking out, and in some cases causing car accidents. Clients may also report feeling ravenous, having bad morning headaches, or having nightmares.

In 2005, the president of the American Society for Bariatric Surgery, Dr. Neil Hutcher, stated he had not seen the severe low blood sugar complication, neuroglycopenia, in his 3000 bariatric operations. Other experts at that time proclaimed the problem was rare, corrected by surgical removal of all or part of the pancreas, and that patients had no further complications. They therefore concluded it was unnecessary to curtail bariatric procedures.

Also in this timeframe, by contrast major hospitals and universities were publishing studies of small numbers of clients with reactive hypoglycemia. Clients were experiencing these dramatic severe drops in blood sugar after meals. Episodes began several years after successful weight loss from bariatric surgery. Considered a delayed or latent effect of dumping syndrome, undigested food quickly passes from the stomach pouch to the small bowel. Excessive insulin is then released, resulting in the rapid and dramatic drop in blood sugar, and onset of symptoms including confusion or passing out.

Blood sugar monitor

Blood sugar monitor

Removal of Pancreatic Tissue for Hypoglycemia After Bypass Surgery

Also in 2005, an important study was released in October by a collaborative group of researchers from Joslin Diabetes Center, Brigham and Women’s Hospital and Beth Isreal. The researchers noted that, while rare, the blood sugar should be evaluated expeditiously in clients exhibiting symptoms. The severe drop in blood sugar is potentially dangerous and the researchers were concerned that they would be attributed to dumping and essentially ignored. It is easy to imagine that many cases may go undiagnosed if they occur 5 years after gastric bypass surgery. By this time, the client may no longer be following up with the bariatric team. Clients and personal physicians may likely attribute symptoms to dumping.

The research team studied three clients who experienced severe hypoglycemic episodes after meals. Two clients caused auto accidents. These clients did not respond to dietary changes or medicines. Their symptoms got worse over time. They all subsequently had all or part of their pancreas removed, which was the emerging treatment for this condition. Examination of the removed tissue revealed an increase above normal in the number insulin producing cells.

Most studies concluded clients seemed to experience decreased severity of symptoms due to drops in blood sugar following removal of pancreatic tissue. For some clients however, the condition recurred.

Carnie Wilson

Carnie has battled to keep her excess weight off.

Carnie has battled to keep her excess weight off.

Poor Glucose Regluation Associated with Weight Gain After Bypass

In 2009 at the American Society for Metabolic & Bariatric Surgery Meeting, Dr. Mitchell Roslin of Lenox Hill Hospital, NY reported another tend of blood glucose issues. He noted common presentations by clients who regained weight after gastric bypass. Patients were understandably alarmed, and reported an uncontrollable drive to eat shortly after meals. Although less dramatic, again a reactive hypoglycemia was suspected. They theorized mildly decreased blood sugar levels due to increased insulin release would increase hunger.

Dr. Roslin and associates studied 67 clients, with an average of four years since gastric bypass surgery. The average age was 48, with 81% female. Average weight pre-surgery was 300 lbs, with an average body mass index (BMI) of 49. (Healthy BMI is 18.5 to 25.) Clients lost an average of 55% BMI of their excess weight. Clients had regained an average of 26 lbs. After glucose tolerance testing, 80% were determined to have glucose abnormalities.

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The specialists found the most dramatic swings in blood glucose were associated with small stomach pouches with wide anastomoses. They concluded that alternatives to the standard gastric bypass procedure, such as incorporation of valves needed to be explored. Further, they suggested that gastric bypass be abandoned, and a completely different approach be explored. Bombshell!

This article is dedicated to Miss Betty, Peter and Amy.


You can read general information on Roux-en-Y and Gastric Sleeve weight loss surgeries on the Johns Hopkins website.

Research from Dr. Mitchell Roslin of Lenox Hill Hospital described abnormal glucose tolerance after gastric bypass surgery. His findings were presented at the 2009 meeting of the American Society of Metabolic and Bariatric Surgery. Dr. Roslin’s findings are reported 6/26/09 by Charles Bankhead in ASMBS: Gastric Bypass Linked to Abnormal Glucose Tolerance.

The Joslin Diabetes Center, a non-profit institution affiliated with Harvard, is the source of information about low blood sugar after stomach bypass surgery in the 10/12/05 post, Severe Hypoglycemia- Complication of Gastric Bypass Surgery.

Dr. Karen E. Foster-Schubert published findings of hypoglycemia in her article, Hypoglycemia Complicating Bariatric Surgery: Incidence and Mechanisms.

The American Society of Metabolic and Bariatric Surgery released a position statement 12/7/16 with recommendations for treating clients with low blood sugar episodes after gastric bypass surgery. The ASMBS Position Statement on Postprandial Hyperinsulinemic Hypoglycemia after Bariatric Surgery was authored by physicians Eisenburg, Azagury, Ghiassi, Grover, and Kim. They did not recommend removal of the pancreas.

Multiple physicians published their findings comparing the Roux-en-Y and Gastric Sleeve procedures. Drs Li, Lai, Ni, and Sun published their article, Comparison of Laparoscopic Roux-en-Y Gastric Bypass with Laparoscopic Sleeve Gastrectomy for Morbid Obesity or Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials, in the Canadian Journal of Surgery in Dec 2013.


rmcrayne (author) from San Antonio Texas on December 25, 2013:

Allison, I have an "rmcrayne" Facebook page. Also Almost Vegetarian rmcrayne

Allison Kaufman on December 25, 2013:

Hi - I know this is an old post, but I'm looking for people who have had/have nesidioblastosis. I couldn't tell from your blog if you did or know someone who did. I also saw you are former military - the person who I am advocating for who was recently diagnosed has military insurance, so I figured there was a slight chance you'd have some insight. Thanks!! I didn't want to leave my email address up here - is there a way I can message you privately?

rmcrayne (author) from San Antonio Texas on December 30, 2011:

Cindy, please see my comment to Jana above. Take this article in to your doctor and insist on a consult back to your surgical group. Maybe also ask for an endocrinology consult.

rmcrayne (author) from San Antonio Texas on December 30, 2011:

Jana, That certainly is scary. Did you contact the surgical group that did your bariatric procedure? I’m so sorry your insurance ran out, and you have such limited options. Try to limit carbs, choosing low glycemic options. Good luck to you.

rmcrayne (author) from San Antonio Texas on December 29, 2011:

Thanks laserlipoNY. I am thrilled that my article might be useful for your clients! I don’t know if you see breast cancer clients for reconstruction, but I’ve written some hubs on post op management after breast cancer too.

cindy on September 26, 2011:

I had a gastric bypass in Dec 2004 and in the last 3 years, I have had a problem with my sugar jumping to 400 or more after eating something sweet or drinking orange juice. After about 45 min I feel dizzy and find that my sugar has dropped to 13-45. I went to a doctor and told her that my father died from complications from diabetes and she checked my sugar that one time and said that there was no reason for further checking because it was fine at that time. What should I do??? The lowest that it has gotten was 13, and I was passing out. My daughter fed me pnut butter, which seemed to bring me back. please email me with suggestions.

Manuel Porras from Germany, Colombia, USA, Panama, Mexico, Spain on September 21, 2011:

Bariatric surgery is a great option for you health

Jana Soriano on August 24, 2011:

I have been experiencing these very low blood sugars...It is very scary! Mine will get down to 28 or lower...I am very surprised that I have not blacked out yet. I have gone the doctor and they did lots of tests and nothing revealed...I don't think I am at the right doctor. I have been complaining of the symptoms of this for about 2 1/2 yrs and the school nurse where I worked finally told me what it was. She started checking my blood sugar for me...she was very concerned. I have recently run out of insurance so I am going to continue to monitor to the best of my ability what I eat and my blood sugar. I do keep the glucose pills in my purse where ever I go. I pray I do not black out!

rmcrayne (author) from San Antonio Texas on November 28, 2010:

My humblest apology CoolJerk. This was one of my early hubs, and I did not yet understand about Creative Commons and attribution. I hope you found my hub otherwise well researched, good information. Could you direct me to any free sources of medical graphics?

CoolJerk on November 28, 2010:

Please immediately remove the above black and white infographic on the Roux-en-Y gastric bypass. It is my infographic and I did not receive any request to use it on this site nor did I give any permissions. A photo credit is not the same thing as taking a portfolio piece from my Flickr account and using it wherever you like.

I'd prefer to go this route before filing a DMCA Complaint with Hub Pages.

Thank you for understanding.

rmcrayne (author) from San Antonio Texas on August 14, 2010:

Thank you lapband. I have made the correction.

lapbandexpert from The Colony, Texas on August 11, 2010:

Sharon Osbourne did not have a Gastric Bypass she had the Lap-Band VERY different

rmcrayne (author) from San Antonio Texas on July 11, 2010:

Thanks for reading and commenting VivekSri.

VivekSri on July 10, 2010:

What an information and solid looking post-op photos. Seems that's no big deal either. Keep posting.

rmcrayne (author) from San Antonio Texas on January 08, 2010:

habee my health was going down the tubes too until I made the switch to alternative medicine. I used to be on iron, potassium and B-12 shots, and 11 prescription and OTC meds. I have one friend who had the surgery and has done well so far, and one who is the reason I know about this problem.

Holle Abee from Georgia on January 08, 2010:

I considered having this a couple of years ago. I've gained a lot of weight since I developed health problems and am not very active anymore. My doctors told me NOT to have the weight-loss surgery because of my bouts with anemia. Sometimes my hemoglobin drops to 7, even with taking vitamins with iron plus liquid iron (yuck). I have a friend who had this surgery, and he's done wonderfully!

on December 15, 2009:

good hub

rmcrayne (author) from San Antonio Texas on September 21, 2009:

For you lrohner, I’ll consider it. It would be much easier however to tackle any “medical” topic once I’m back at WHMC volunteering, because I’ll have access to the online medical library.

From what I know at this point:

Long before surgery, the body adapts to try to keep up with the insulin demands. Think of a healthy sized body as a quart container. There is an amount of insulin that is optimal for function for 1 quart. At 2 quarts, the body may be able to increase production to have enough insulin. Person may not yet be diabetic. At this point, the pancreas actually has an increased number of islet cells (the insulin producing cells of the pancreas). As a person becomes more obese, there is a point at which the body can’t keep up, they will be diabetic, but still have “extra” islet cells that a healthy weight person wouldn’t have.

Bariatric surgery is thought to “cure” diabetes for most clients, in part because of the insulin response. Experts think that for most people after gastric bypass, the body reverses the process with the islet cells in the pancreas. The number of islet cells decreases. For those that develop this “reactive hypoglycemia”, the pancreas keeps these extra cells, therefore has too many. When they eat, especially a high carb meal, they have 2 quarts-equivalent of insulin, but now their container is only 1 quart-sized.

So, another hub later? Or does this answer the question, in which case I’ll polish a bit more and include it in this hub. Once back at WHMC, I’m going to look up “Miss Betty” and hopefully interview her for another hub. She said her surgeon told her this may be happening in 20% of bypass clients. Wonder what Dr. Hutcher has to say about that.

lrohner from USA on September 20, 2009:

With a diabetic daughter that suffered from severe hypoglycemia for years and a granddaughter just recuperating from Congenital Hyperinsulinism, I'm really curious as to cause of this hypoglycemia. Would you consider delving into that a bit more on another hub?

rmcrayne (author) from San Antonio Texas on September 20, 2009:

Thanks for the kudos girls!

@AW, click on the link near the end. The researchers recommended vertical-sleeve gastrectomy and duodenal switches, whatever that all means. Of course that would be new territory. Will there be equal or worse problems from that procedure down the line? It did seem this problem was almost exclusive to the roux n Y. At any rate, absolute best of luck with your surgery.

@Lisa, they do fear that clients will possibly develop diabetes. The whole thing sounds rash doesn’t it? I know someone this happened to. They removed half of her pancreas and she still had these pass-out drops in blood sugar. She fell and broke her wrist and had the longest wrist MRI report I had ever seen. Likely because osteoporosis is worsened by bypass too I think.

I will be going back and adding links for more of my sources, but wanted to squeak this in before the new HubMob topic launches tomorrow.


lrohner from USA on September 20, 2009:

Great hub, Rosemary! I'm curious about the pancreatic surgery to reduce hypoglycemic episodes. Can/does that lead to diabetes eventually?

atomswifey from Michigan on September 20, 2009:

WOW great hub here!

The surgery I have opted for is not the full gastrric bypass. It is the insertion of the lap band which is not exactly the same thing, but I will talk to my doctor about all of this my next appointment prior to surgery.

Thank you for all this information!


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