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What to Know About Gastric Bypass Failure

What to Know About Gastric Bypass Failure

Gastric bypass is the second most common bariatric operation in the world. As with any surgical procedure, complications are possible. On the other hand, weight loss surgery can be lifesaving for many patients.

Gastric bypass failure occurs when patients experience severe side effects or when they are unable to lose a significant amount of weight. Overall, gastric bypass failure rates remain low.

In cases with severe complications, revision surgery may be recommended.

Possible Side-Effects and Complications Associated with Gastric Bypass

Gastric bypass is a safe and effective surgery for the treatment of obesity. However, surgery carries the possibility of risks and side effects, such as diarrhea, malabsorption. The majority of side effects after gastric bypass are minor and  can be easily solved. But sometimes, patients experience more severe difficulties that can lead to additional health problems.

Complications after gastric bypass can happen in the early post-op period, or later on down the road. The most common gastric bypass complications that may occur soon after surgery include:

  • Anthesthia or medication-related complications
  • Leak
  • Blood clotting
  • Pulmonary embolism
  • Bleeding
  • Infection

Some complications happen long after the surgery. The most common complications that may happen later on include:

  • Vitamin and mineral deficiencies
  • Protein deficiency
  • Narrowing/scarring  of bowel connections
  • Internal hernia
  • Dumping syndrome
  • Failure to lose sufficient weight
  • Weight regain
Weight regain is possible after bariatric surgery. It's especially important to monitor your diet and exercise.

Failure to Lose a Significant Amount of weight after Gastric Bypass

The gastric bypass procedure is considered the gold standard of weight loss surgery procedures. On average, patients can expect to lose 60-80% of their excess weight. Weight loss is likely to occur over one to two years after surgery. However, not all patients lose the same amount after gastric bypass.

Gastric bypass does not lead to weight loss on its own, but it does help patients achieve weight loss. Weight loss is more successful after gastric bypass when patients follow a healthy diet combined with regular physical activity. Lack of a healthy diet and not following nutrition recommendations after surgery is one reason for gastric bypass failure.

Avoiding or Correcting a Failed Gastric Bypass

The first line of defense against failed gastric bypass is before surgery even happens. It's essential to get educated before surgery about appropriate amounts of protein and calories to maximize your weight loss. Gastric bypass limits the amount and kinds of food that you can handle after surgery. Your diet quality is very important to ensure adequate nutrients. It's also important to learn what and how to eat after surgery to avoid gastric bypass failure. Possible complications associated with poor nutrition include weight regain.

If you begin to gain weight after surgery, talk to your healthcare team. You may have a good idea of what's causing your weight gain. A thorough evaluation may be needed to determine if other factors — medical, psychological, lifestyle — are involved.

Weight gain is a chance to examine your eating and exercise habits.

Down the road, it's not uncommon to eventually regain some of the weight loss after surgery. It's important to keep in mind that obesity is a chronic disease. Bariatric surgery provides a powerful tool for significant weight-loss, but without proper care, "the tool" can lose its effectiveness, leading to weight regain.

A stall in weight loss happens in many weight loss journeys, even after weight loss surgery. Try to determine whether you are truly in a weight loss plateau. Don't only use the scale as a way of measuring progress. If you are working out consistently, you might be losing fat and gaining muscle, making it seem like you aren't losing weight. Measure progress by the way you feel and how your clothes fit.

Evaluate each piece of your new lifestyle habits. Could you be eating more calories than you think? Is your exercise program not challenging enough anymore?

Sometimes, revision surgery is needed when the gastric bypass fails. It's important to remember that treating obesity is similar to managing other chronic diseases. One treatment isn't always enough. When revision surgery is needed, your physician will consider the risks and benefits of another operation.

Often, weight regain can be fixed with getting back on track with nutrition.


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Morgyn Clair, MS, RDN


Morgyn is an RD specializing in weight management and surgical weight loss. She has a master's in clinical nutrition and dietetics, and currently works as a clinical dietitian in a physician’s office.

Gintas Antanavicius, MD, FACS, FASMBS

Medical Reviewer

Dr. G is a co-founder of BariBuilder. A US-based expert surgeon with over 10 years of bariatric experience, he regularly publishes research in medical journals like SOARD, Obesity Surgery, etc.