Gastric Bypass Surgery

Gastric Bypass: Procedure & Results Guide

You probably found this page because you are considering having weight loss surgery.

In order to decide if having gastric bypass surgery is right for you, you’re going to need learn a little bit about it.

Since most of us reading this page are dealing with a similar situation of struggling with morbid obesity, most of us want the same questions answered initially:

  1. Major surgery sounds scary as heck. Is gastric bypass surgery safe?Yes, but it carries the same risks as any major surgery. To put the safety (risk of dying) into perspective, it is safer than having a C-section (1). In addition, most patients must learn to deal with certain complications or side effects (more on all of this below).
  2. How much weight will I lose?A lot. And, quickly.
  3. Can I still eat the foods I love?It depends on your current diet. The overwhelming majority of the time, you’ll be eating “healthy” food in smaller quantities than you’re used to. This will be a massive and permanent lifestyle change.
  4. Can I afford it?If your health insurance covers it, yes. If you don’t have health insurance, you’ll need to read about your options below.
  5. If I follow the rules, will my health improve and will I feel better?Most definitely.

We know you need more than the short answers above (and that you have more questions!), so we laid out this page to answer your questions in the simplest way possible while still providing a lot of information.

The Table of Contents directly below is set up as a guide to walk you through learning about gastric bypass surgery. Just click “Is Gastric Bypass Surgery Safe”, and you’ll be on your way to deciding if surgery is right for you.

If you have a specific topic that interests you most, feel free to skip right to it by clicking it below.


Click on any of the topics below to jump directly to that section

  1. Is Gastric Bypass Surgery Safe?
  2. How Much Weight Will I Lose?
  3. How Much Does It Cost?
  4. Am I A Good Candidate?
  5. How Will My Diet & Lifestyle Need To Change?
  6. Will I Feel Better And Be Healthier?
  7. Will My Friends And Family Look At Me Funny?
  8. Do I Need To Do Anything Before I Have Surgery?
  9. How Long Will It Take Me To Recover?
  10. Are There Other Weight Loss Procedures to Consider?
  11. How Do I Find A Good Surgeon Near Me?
Bariatric Surgery Source

Is Gastric Bypass Surgery Safe?

Yes. It’s very safe. The survival rate is 99.8% (2).

To put this in perspective, remaining morbidly obese is likely to be much riskier over the long-term than having gastric bypass surgery. For example, morbidly obese patients who have bariatric surgery are 89% less likely to die over any 5 year period than morbidly obese individuals who do not have surgery (3).

The surgery mainly consists of your surgeon separating the top portion of your stomach from the bottom portion and rerouting your intestines.

SLIDESHOW: Tap here to see how you will lose weight with the gastric bypass procedure.

After the procedure, you’re left with a much smaller stomach “pouch” at the top that will cause you to feel full sooner while eating and will make it very difficult to overeat. In addition, your food will “bypass” the top portion of your intestines where much of it is usually absorbed.

As a result, you’ll lose a lot of weight very quickly.

We understand that this may sound scary, but it has become a routine procedure with a very low risk of death.

However, as many as 1 out of every 10 gastric bypass patients do experience a non-life-threatening complication at some point (4). The most common complications include:

  • Stomal Stenosis (narrowing of the opening from the stomach to your intestine) – About 5 out of every 100 patients
  • Wound Infection – About 3 out of 100
  • Bowel Obstruction – About 3 out 100
  • Leak – About 2 out of 100
  • Gastrointestinal bleeding – About 2 out of 100

For more information about potential complications, click here.

Most patients must also learn to manage digestive issues like dumping syndrome, indigestion, and certain food intolerances. Sagging skin from extreme weight loss and long-term weight regain are also common issues. Click here for more about potential side effects.

How Much Weight Will I Lose After Gastric Bypass Surgery?

This is the million-dollar question, right?!

The reason you’re considering gastric bypass surgery is so you can live your life at a healthier weight.

Significant weight loss usually happens fast after surgery. Within 3 months, the average patient loses about one-third of their excess weight. By the 1-year mark, almost two-thirds of the excess weight will be gone.

Click Here to See How Much Weight You Could Lose

Click here for more pictures and videos.

Many patients reach “peak” weight loss between 1 and 2 years, then gain a little back. But long-term results are still impressive, with the average patient keeping about 60% of their excess weight off after 5 years.

Keep in mind that these are averages – “middle of the road” results. Patients who eat the right foods, exercise regularly, and follow their surgeon’s advice can lose even more, while patients who veer off-track lose less.

By 5 years after surgery, the average patient has kept off over half of their excess weight.

You can avoid weight regain by:

  • Working closely with your surgeon’s dietitian or nutritionist
  • Using a personal trainer
  • Attending in-person or online support groups at least twice per month
  • Keeping a food journal
  • Having the support of your family and friends
  • Maintaining your motivation and dedication
Bariatric Surgery Source

How Much Does Gastric Bypass Surgery Cost?

This all comes down to whether your health insurance covers bariatric surgery (another term for weight loss surgery). If your insurance covers bariatric surgery, then gastric bypass surgery will also be covered.

Click Here to Check Your Insurance

In addition to using the tool above, there are two main ways to confirm whether your health insurance covers weight loss surgery.

  1. You can call your health insurance company
  2. You can submit your information to a surgeon’s office and let the staff check for you (often done for free from home)

If you do not have insurance that covers bariatric surgery, the average cost of gastric bypass ranges from $15,000 to $20,000, depending on your area. Click here to read about ways you might be able to pay for surgery.

What’s Next If My Insurance Does Cover Gastric Bypass?

If your plan covers it, you will still need to confirm that you have a qualifying body mass index (BMI) over 35 with health problems or if your BMI is over 40, your insurance will cover your surgery even without health problems.

If your BMI qualifies, and you’re ready to proceed, it’s time to contact a surgeon to start the process. In addition to learning your medical history and scheduling a psychological exam, you’ll also need to complete a medically supervised diet program. All of this will be managed by your surgeon’s staff.

Even with insurance, you will still have to pay a portion of the costs. Your final out-of-pocket costs will depend on:

  • Your insurance plan’s deductible, coinsurance, and out-of-pocket maximum
  • How much you’ve already paid towards these throughout the year for other medical services (for example, if you’ve already reached your annual deductible and out-of-pocket maximum, you may not have to pay anything more for your weight loss surgery procedure)

See our Insurance Guide for everything you need to know about getting insurance to pay for surgery.

What Are My Options If My Insurance Doesn’t Cover It?

If you don’t have insurance that covers the procedure, the good news is that:

  • Your insurance may still cover some of your costs, such as pre-op testing, even if weight loss surgery is not an included benefit under your plan
  • Special discounts are usually offered to “self-pay” patients
  • Your out-of-pocket costs may be tax deductible
  • Loans are available to make it more affordable

See our Gastric Bypass Cost & Financing page for more information.

Am I A Good Candidate for Gastric Bypass Surgery?

There are two main things to consider in order to judge if you’re a good candidate for surgery.

  1. Is your body mass index (BMI) high enough to qualify you for surgery?
  2. Are you ready to make the necessary lifestyle changes to be successful?
Click Here to See Your BMI

Your BMI has to be above 40 to “automatically” qualify. Otherwise, it can be as low as 35, but only if you have a serious, obesity-related health issue.

Serious obesity-related health problems most commonly include:

  • High blood pressure
  • High cholesterol
  • Type 2 diabetes
  • Sleep apnea
  • Many others (see Health Benefits section above)

Only you know if you’re willing to make the changes to be successful, but be honest with yourself when you’re reading the required changes below.

Also, it’s important to know that you shouldn’t plan to get pregnant for at least 1 to 2 years after surgery.

See our Gastric Bypass Qualifications page for more information about who qualifies and who does not.

For a list of frequently asked questions about qualifying, see our “Do I Qualify For Weight Loss Surgery?” page.

How Will My Diet & Lifestyle Need To Change After I Have Gastric Bypass Surgery?

Here are a few high level considerations that apply to most patients:

  • You’ll probably need to eat healthier than you have in the past. If you stray too far from your surgeon-recommended diet, you will experience very unpleasant digestive issues like dumping syndrome, indigestion, nausea, and vomiting.
  • You’ll need to take vitamins & supplements for the rest of your life. Your surgeon will tell you the what and the when (and you can read about it below).
  • You’ll have to exercise. No one is asking to run a marathon next week, but you’ll need to be committed to being active!
  • You should regularly attend a weight loss surgery support group. You can do this in-person or online which really helps people stay on track.

Your surgery is only a tool. Long-term success requires diligence and sometimes difficult change in other areas.

The following sections give you a bit more detail about what to expect before and after surgery. Every surgeon is different, and every patient is different. Please talk with your surgeon before acting on any of the following advice.

Food & Drink: Your Diet Transition Schedule

Diet requirements by time frame are summarized below:

  • 3+ Weeks Before Surgery – Practice your post-bypass diet
  • 2 Weeks Before Surgery – High protein, low sugar, low carbs
  • 1 Week Before Surgery – Stop or change some medications
  • 2 Days Before Surgery – Clear liquids only
  • Midnight Before Surgery to 7 Days After Surgery (Varies by Surgeon) – Nothing to eat or drink
  • In Hospital (Varies by Surgeon) – Clear liquids only
  • Day 1 to Week 2 After Surgery (Varies by Surgeon) – Add thicker drinks & smooth foods (no chunks)
  • Day 2 to Week 3 After Surgery (Varies by Surgeon) – Slowly test pureed & soft solid foods
  • Day 3 to Weeks 4+ After Surgery (Varies by Surgeon) – Slowly test solid foods

For details about each stage, see our Gastric Bypass Diet Guide.

Vitamins & Supplements: Your 5 Lifelong Supplements

Since gastric bypass is a “malabsorptive” procedure by nature, it carries a high risk of malnutrition. Patients must be extremely diligent about taking prescribed vitamins and supplements or risk serious vitamin deficiency.

Your daily vitamin regimen will include:

  • Multivitamin
  • Calcium
  • Folate (folic acid)
  • Iron
  • Thiamin (vitamin B1)
  • Vitamin D
  • Vitamin B12

For more information, see our Bariatric Vitamins page.

The Importance of Exercise After Weight Loss Surgery

Getting proper exercise is second only to diet in determining how much weight you’ll lose.

For example:

  • Patients who work out two and a half hours per week have been found to lose 6% more than patients who don’t exercise (5).
  • Research shows that patients who work out regularly recover from surgery more quickly and see better improvements in their health (6).

What does “proper exercise” mean? Shoot for a 30 to 45 minute workout 3 or 4 days per week.

Click here to learn more about exercise after weight loss surgery.

Your Brain: Less Hungry, Careful About Food Addiction, New Mentality Will Change Your Behavior

Ghrelin Hormone & Hunger

The big diet changes reviewed above may be easier than they sound for two reasons:

  1. You may permanently feel less hungry following surgery since the production of a key hunger-causing hormone, ghrelin, will be reduced
  2. Your stomach will be much smaller, causing you to feel full much sooner while eating

Food Addiction

If not addressed prior to surgery, food addiction can lead to long-term weight regain for gastric bypass patients. If you struggle with food addiction, talk with your surgeon before moving forward with surgery.

To find out if you may be suffering from food addiction, take our Food Addiction Quiz.

The Importance of Regularly Attending a Support Group

Like other difficult times in your life, having the help and support of a compassionate group of people who know exactly what you are going through can work wonders.

In fact, patients who regularly attend support groups lose more weight and even recover from surgery more quickly.

Your surgeon will be able to recommend a good support group at their clinic or in your area.

Will I Feel Better And Be Healthier If I Have Gastric Bypass Surgery?


Gastric bypass results in complete “resolution” (cure, as long as weight loss is maintained) of many obesity-related health problems, including those listed below:

  • Diabetes
  • Sleep apnea
  • Hypertension
  • Asthma
  • Cholesterol problems
  • and at least 10 other conditions

Patients who aren’t cured usually experience a noticeable improvement.

On top of that, you’ll be walk up a flight of stairs without sweating and tying your shoes won’t feel like a workout!

Note that patients who have a strict follow-up schedule with their surgeon at 3-, 6-, and 12-months post-op see greater improvements in or remission of their diabetes, high blood pressure (hypertension), and high cholesterol than patients who skip these visits (7).

Your dramatic weight loss will also improve your joint health. For every pound of weight lost, there is a 4 pound reduction in pressure on the knee (8). This improves mobility and reduces pain in the knees.

Further, 88,000 weight loss surgery participants were involved in data collection for cancer research. Results state that patients who undergo weight loss surgery have 33% less risk of developing cancer (9).

Risk rates were even further reduced for obesity-related cancers, including (10):

  • Colon cancer
  • Postmenopausal breast cancer
  • Endometrial cancer
  • Pancreatic cancer
Click Here to See a Full List of Health Benefits

Will My Friends And Family Look At Me Funny If I Have Gastric Sleeve Surgery?

It’s possible you’ll hear whispers that you took the “easy way out” by having surgery. You can brush that right off because all that comment really shows is others’ lack of understanding about bariatric surgery… because there is nothing “easy” about it.

Jealousy can also rear its ugly head. People that you would want and expect to be happy for you may not be comfortable with the attention your weight loss is bringing your way.

Hopefully, the majority of your friends and family will be smiling ear-to-ear because you’ll be more active and able to do more things with everyone. Your newfound energy can benefit everything from getting back into a sport you love to having more sex!

Positives reported by most patients include:

  • Being treated with more respect
  • Getting more compliments from others
  • Building deeper relationships by being able to physically keep up with kids and more physically fit friends
  • Increased self-confidence and the effect that has on others
  • Getting more romantic interest from others
  • Improvements in quality of sexual life (11)
  • No more obesity discrimination. For example, strangers tend to be nicer to thin people

But your relationship changes won’t be all roses. People who you’ve known for a long time will not be used to the way you look and may not know how to act around you. For example:

  • Could your new self-confidence create conflict with people who are used the “old” you?
  • How will overweight friends or family members feel when you’re losing weight but they are not?
  • Will your friends or family make it difficult for you to stay on track by making bad diet choices?
  • Will your new healthier diet and smaller portion sizes make meals with others awkward?
  • How will your coworkers react? Should you even tell them you are having surgery?
  • Could intimacy with your spouse or partner be affected?
  • Could your spouse or partner become jealous now that others are noticing you more?

And what about the new “skinny lens” you see the world through? For example, when interacting with others you might think:

  • “How do I handle obesity discrimination now that I’m on the ‘other side’?”
  • “Would this person be treating me the same way if I hadn’t lost all this weight?”

Be prepared for both the good and the challenging “shocks” of dramatic weight loss following surgery.

For real life experiences and advice from other patients, see our Relationships After Weight Loss surgery page.

What Do I Need to Do Before I Have Surgery?

Yes. But the biggest thing you’ll have to do is change your diet.

Why? Because:

  • Losing as much weight as possible before your surgery will reduce the chance that anything goes wrong during surgery
  • Patients who lose more weight before surgery tend to lose more weight after surgery
  • Slipping into old habits equals weight regain. The sooner you can establish good diet and exercise habits, the more likely you will be to maintain them after surgery

Your surgeon will discuss all of this with you during the weeks leading up to surgery, as well as:

  • Asking you to complete a health assessment, including questions about your medical history, medications, and surgical history
  • Ordering certain tests like an ECG, x-ray, and blood tests
  • Establishing a pre-surgery diet regimen, including:
    • 2 Weeks Before
      • No sugar
      • Lower carbs
      • Increased protein
      • Increased veggies
      • Plenty of fluids
    • 2 Days Before
    • 12 Hours Before
      • No food or drink, no tobacco

On surgery day, you’ll perform the typical pre-surgery routine:

  1. Remove all clothes and jewelry
  2. Put on your hospital gown
  3. Meet with your nurse and anesthesiologist
  4. Start your IV
  5. Receive medication for relaxation and sleep

See our Preparing for Weight Loss Surgery page for more information.

How Long Will It Take Me To Recover From Gastric Bypass Surgery?

You’ll be “fully recovered” in 4 – 6 weeks after your surgery, although most patients are able to return to work in 1 – 3 weeks.

Below are the details on what to expect from the time you enter the hospital to the time you’re living your “new”, post-op life.

You’ll arrive at the hospital at least two hours before surgery to allow for prep time. The gastric bypass procedure itself will take about 4 hours to perform. Immediately after surgery, you’ll have a dedicated nurse to manage your pain and check your vitals.

Most patients are discharged from the hospital in 2 – 3 days.

Click here for more about what to expect in the hospital.

Your recovery may include challenges like nausea, digestive issues, and body changes that will go away over time or after adjusting diet/lifestyle habits.

After you return home, you will have a follow up visit with your doctor within 2 weeks to ensure you are recovering well and to address any questions. Later visits will be scheduled as-needed.

See our Gastric Bypass Recovery page for an in-depth recovery timeline and details about each aspect of recovery.

Is Gastric Bypass Surgery The Best Surgical Option For Me?

It depends.

The most popular procedure in the United States is currently gastric sleeve, not gastric bypass, because the sleeve results in similar weight loss with a less complex procedure and lower complication rates.

However, gastric bypass is the 2nd most popular procedure for good reason.

Its dietary restrictions and the repercussions for “cheating” are helpful towards long-term weight loss for many patients.

In addition, gastric bypass results in better health improvement, and it is much better than gastric sleeve if you are on blood thinners to reduce the risk of marginal ulcers.

Newer procedures like gastric balloon and AspireAssist are becoming more popular, but their numbers are nowhere close to the gastric sleeve or gastric bypass. Lap-Band is making a bit of a comeback, but it is no longer widely performed.

Below is the full list of positives and negatives of gastric bypass versus the other available weight loss procedures.

Gastric Bypass Positives

  • Weight loss is usually in range of gastric sleeve and much better (on average) than after LAP-BAND® surgery or gastric balloon (but less than duodenal switch). The AspireAssist needs more research, but initial results show a weight loss potential less than gastric bypass.
  • Health Improvement is generally better than after gastric sleeve, LAP-BAND®, or gastric balloon (but not as good as duodenal switch). Initial research shows AspireAssist will have similar health improvements to gastric balloon, but more research is needed to confirm.
  • Short-term risk of gastric bypass is similar to that of gastric sleeve and lower than duodenal switch (but higher than LAP-BAND®, gastric balloon, or AspireAssist).
  • Long-term risk of gastric bypass is lower than duodenal switch (but higher than gastric sleeve, and LAP-BAND® surgery; long-term data not yet available for balloon or AspireAssist).
  • There is no external device left inside the body as there is with LAP-BAND®, gastric balloon, and AspireAssist, so there is no risk of device-related complications. While the risk of device-related complications is relatively low for gastric balloon and AspireAssist, it is a concern and should be considered for LAP-BAND®.
  • If you are on anticoagulation medication (blood thinners), compared with gastric sleeve, gastric bypass surgery is probably a better choice to reduce the risk of marginal ulcers.

Gastric Bypass Negatives

  • Not reversible – Unlike LAP-BAND®, gastric balloon, and AspireAssist, gastric bypass surgery (along with gastric sleeve and duodenal switch) should be considered irreversible – once your stomach size is reduced and your intestines are rerouted, it is very it is very difficult and uncommon for the procedure to be reversed.
  • Weight loss (on average) is usually lower than duodenal switch (but higher or similar to all other procedures).
  • Health Improvement is generally not as significant as after duodenal switch (but is generally better than all other procedures).
  • While survival rate is extremely high at 998 out of every 1,000 patients, risk of gastric bypass complications is higher than all other procedures except duodenal switch. Early complications occur in about 1 out of 10 patients while late complications occur in about 1 out of 7 (12) (13)
  • The two primarily “malabsorptive” procedures, gastric bypass and duodenal switch, are more complicated to perform and include the rearranging your digestive system. As a result, they have a:
    • Longer recovery
    • Higher risk of vitamin deficiency (and therefore require more daily supplements)
    • Higher costs
  • Dumping syndrome is experienced by up to 7 out of 10 gastric bypass patients, although many patients report this being a “good thing” since it helps them keep their diet on track (see more in the Downsides section above).

For further comparison of gastric bypass surgery to other procedures, see our Types of Bariatric Surgery page.

These pages will help you better understand the differences between gastric bypass and other popular procedures:

“Stomach Stapling”, or horizontal gastroplasty, is an old procedure that is no longer performed. Click here for more details.

For a more-detailed comparison, see our Types of Bariatric Surgery page.

To learn which procedure is best for you, click here to take our Choose the Right Procedure Quiz.

How Do I Find A Good Surgeon Near Me?

You can read everything available on the internet, but nothing can fully replace an in-person consultation with a great bariatric surgeon. If you’re curious about weight loss surgery, find a local surgeon and set one up.

Bariatric Surgery Source

To view references for this page, click here.

* Disclaimers: Content: The information contained in this website is provided for general information purposes and your specific results may vary depending on a variety of circumstances. It is not intended as nor should be relied upon as medical advice. Rather, it is designed to support, not replace, the relationship that exists between a patient/site visitor and his/her existing physician(s). Before you use any of the information provided in the site, you should seek the advice of a qualified medical, dietary, fitness or other appropriate professional. Advertising: Bariatric Surgery Source, LLC has entered into referral and advertising arrangements with certain medical practices, original equipment manufacturers, and financial companies under which we receive compensation (in the form of flat fees per qualifying action) when you click on links to our partners and/or submit information. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Read More

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