Weight Loss Surgery – Types, Safety, Benefits, And Side Effects

Medically reviewed by Patrick, MD, FACS Patrick PatrickMD, FACS facebook_iconinsta_icon
Written by , MSc (Biotechnology), ISSA Certified Fitness Nutritionist Charushila Biswas MSc (Biotechnology), ISSA Certified Fitness Nutritionist Experience: 6 years

Weight loss surgery, or bariatric surgery, is a surgical procedure that is usually only recommended if you have a BMI ranging from 35-40, or above, and suffer from obesity-related diseases such as diabetes and heart disease. Studies have shown that bariatric surgery reduces obesity-related complications and prevents weight regain after the surgery, for a healthier lifestyle. Continue reading to learn more about weight loss surgery, its safety, success rate, and much more.

What Is Weight Loss Surgery And How Does It Work?

Weight loss (known as bariatric) surgery, is a surgical procedure performed on the digestive system by highly skilled medical professionals to help extremely overweight patients lose weight. Unlike liposuction, where a certain amount of excess fat is removed from the body, weight loss surgery focuses on limiting the amount of food consumption and absorption.

This is done in two ways. First, by restricting the amount of food you can hold in your stomach, thereby, making you feel full sooner and preventing overconsumption. Secondly, by shortening your small intestine, to prevent absorption of food molecules that gets converted into fat when it is not used as an energy source.

Bariatric surgery is minimally invasive and can be done using a laparoscope. This is the most preferred method, as it causes less pain and speeds up the healing process (2). However, a few open bariatric surgeries can also be performed depending on the patient’s needs and health condition.

Back To TOC

Does Weight Loss Surgery Work?

Weight Loss Surgery - Does Weight Loss Surgery Work
Image: Shutterstock

Weight loss surgery, or bariatric surgery, is proven to be effective for morbidly obese patients. Since it prevents overeating and reduces the absorption of nutrients, you will gradually lose weight, and it will feel like you are losing weight naturally.

However, diet and lifestyle changes will need to be followed to prevent weight gain after weight loss surgery. Patients suffering from depression or binge eating disorders also need to take extra precaution, as they are more prone to gaining the weight back (3).

It is important to understand that although bariatric surgery aids in weight loss, a permanent lifestyle change is needed, to avoid gaining the weight back.

Back To TOC

Criteria For Weight Loss Surgery

Weight Loss Surgery - Criteria For Weight Loss Surgery
Image: Shutterstock

Weight loss surgery is not for everyone. For example, some patients may feel that they are overweight when they are not. If you feel the need to lose a little weight, and you are able to accomplish this by altering your lifestyle, diet, and exercise, surgery may not be right for you. So, how does someone know if weight loss surgery is the right option? Experts have designed a screening process and checklist to screen patients suitable for bariatric surgery.

Here are the basic criteria to qualify for weight loss surgery:

  • You have a BMI (Body Mass Index, calculate here) of 35-40 or more.
  • You have a BMI of 35-40 or more, and suffer from obesity-related diseases.
  • You have a BMI of 30-35, and suffer from obesity-related diseases.

Apart from this, a questionnaire or evaluation may be provided by your doctor to help determine whether you are a good candidate for bariatric surgery. Your doctor will make the decision based on numerous factors, to ensure this type of surgery is successful and will be beneficial for you in the long run.


[ Read: How To Lose Weight Fast At Home ]

Now, let’s take a look at the types of weight loss surgery.

Back To TOC

Types Of Weight Loss Surgery

There are four mainly used methods for bariatric surgery. Your doctor will determine which type of surgery will be best for you, as each has its own pros and cons.

1. Roux-en-Y Gastric Bypass

Weight Loss Surgery - Roux-en-Y Gastric Bypass
Image: Shutterstock

This is the “gold standard” of bariatric surgery, also known as a Gastric bypass.


First, the surgeon staples the upper part of the stomach and creates a small pouch. Then, the small intestine is cut and reattached to the lower part of the small intestine, to create a new smaller pouch. Next, the upper part of the small intestine is attached to the lower portion. This makes the stomach smaller. Therefore, you cannot eat as much since you will feel full sooner.

Attaching the lower part of the small intestine to the newly created small pouch will limit the absorption of calories, and the reattachment of the upper and lower small intestine will aid in proper digestion.

  • Suppresses appetite.
  • Aids long-term weight loss.
  • Reduces the risk of type 2 diabetes.
  • Increases satiety.
  • Complex procedure.
  • Longer recovery time.
  • May lead to vitamin and mineral deficiency. Patients should take vitamin and mineral supplements as long as they live.
  • Patient should adhere to a good lifestyle
  • Requires follow-ups.

2. Gastric Sleeve Surgery

Weight Loss Surgery - Gastric Sleeve Surgery
Image: Shutterstock

A sleeve gastrectomy or laparoscopic sleeve gastrectomy is another commonly used method.


The surgeon removes 80% of the stomach. The remaining stomach, which now looks like a banana, is too small to hold too much food. Therefore, you eat less and lose weight.

  • Leads to weight loss.
  • Helps sustain the weight loss.
  • Reduces the risk of obesity-related diseases like type 2 diabetes.
  • The major part of the stomach is permanently removed, so it is not reversible.
  • Gut bacteria and hormones get affected, which, in turn, affects metabolism.

3. Adjustable Gastric Band Surgery

Weight Loss Surgery - Adjustable Gastric Band Surgery
Image: Shutterstock

Gastric band surgery, also known as laparoscopic adjustable gastric band surgery, is another option.


The surgeon places a ring with an inner inflatable band at the top part of your stomach, thereby creating a small pouch. It is similar to tying a knot with a band. The remaining part of the stomach remains below the band. Now, the inflatable band is filled with salt water by the surgeon to adjust the opening of the stomach pouch. So, when the stomach is small, you will eat less and prevent weight gain.

  • Induces weight loss.
  • Reduces the amount of food the stomach can hold.
  • Involves no knife procedure.
  • Short hospital stay.
  • Reversible surgery.
  • Lowest rate of post-operative complications.
  • Lowest risk of vitamin and mineral deficiency.
  • Lower success rate.
  • Slower weight loss.
  • The band might slip.
  • A foreign object will remain inside your body.
  • Can result in dilation of the esophagus.
  • The band can have mechanical problems.
  • Requires re-operation.
  • Patient needs to adhere to a strict diet.

4. Duodenal Switch Surgery

Weight Loss Surgery - Duodenal Switch Surgery
Image: Shutterstock

This option, also known as biliopancreatic diversion with duodenal switch (BPD/DS), is the most complex weight loss surgery.


First, a gastric sleeve surgery is performed. Next, the duodenum and the last portion of the small intestine are divided, before joining these two parts together. About three-fourths of the small intestine is bypassed. The upper part of the small intestine that carries pancreatic enzymes and bile (important for digestion and absorption of fats and protein) is reconnected to the last portion. You will eat less since the small stomach pouch cannot hold too much food. Since the pancreatic enzymes and bile get mixed at the end of the small intestine, fewer calories will get absorbed.

  • Aids greater weight loss.
  • Reduces calorie absorption by 70%.
  • Increases satiety.
  • Best surgery for treating type 2 diabetes.
  • Requires longer hospital stay.
  • Causes vitamin and mineral deficiency.
  • Complex procedure and can be risky.
  • You have to stick to a strict diet.
  • Requires follow-up compliance.

These are the four weight loss surgery procedures that can help you lose the fat and lead a healthier lifestyle. But the main question is, how much weight will you lose?

Back To TOC

How Much Weight Will You Lose?

Bariatric or weight loss surgery is highly effective. The weight loss can range between 12-39% of the original body weight or 40-71% excess weight loss (4). This is a huge number, and it has changed the lives of many obese patients. It is proven that bariatric or weight loss surgery is a life-changing experience, but you should know what to expect before making this decision.

[ Read: How To Tighten Skin After Weight Loss ]

Back To TOC

What To Expect Before Weight Loss Surgery

Weight Loss Surgery - What To Expect Before Weight Loss Surgery
Image: Shutterstock

Before weight loss surgery, you may need to meet and discuss your condition with your doctor, psychiatrist, and dietitian. You will also be educated on what you should expect out of this surgery. Here’s what you should know:

  • Your doctor will do a thorough physical exam, check your blood report, and go through your medical history.
  • If you smoke, you will have to stop smoking six weeks, or more, before the surgery.
  • The dietitian will tell you what and how much to eat and what kind of lifestyle you should follow post-surgery.
  • The psychiatrist will do an assessment to know if bariatric surgery will help you.
  • Bariatric or weight loss surgery will help you lose the weight over a period of 12-15 months. You will not lose the weight overnight.
  • Most weight loss surgeries are deemed safe, and positive results. However, if you do not lead a healthy lifestyle afterwards, you might regain the weight.
  • You will have to go to follow-up appointments post-surgery.
  • Talk to your doctor if you are phobic to needles, a foreign object inside your body, or anything that you are concerned about.


Now, let me answer the most important question – is weight loss surgery safe? Here’s your answer.

Back To TOC

Is Weight Loss Surgery Safe?

Bariatric or weight loss surgery are considered safe procedures for the right candidates. You must have a detailed discussion with your doctor to know if weight loss surgery is what you want, and if it is the right decision for you. If you do decide to go for it, the next thing to plan for is the cost of the surgery.

Back To TOC

Weight Loss Surgery Cost

Weight Loss Surgery - Cost
Image: Shutterstock

The cost of weight loss surgery can typically range from $14,000-$23,000 on average. Talk to your insurance company to know if this surgery will be covered or not.

Before taking the next step, let’s discuss the benefits and side effects of weight loss surgery, so you can make an informed decision.

[ Read: Best Weight Loss Clinics In India ]

Back To TOC

Weight Loss Surgery Benefits

There are many benefits of weight loss surgery. Here’s what you should know:

  • Bariatric surgery aids in long-term weight loss.
  • It prevents excess weight regain.
  • Reduces the risk of obesity-related diseases.
  • Increases longevity.
  • Improves the quality of life.
  • Improves mental health.

Back To TOC

Weight Loss Surgery Side Effects

Here are a few side effects of bariatric surgery:

  • It can lead to vitamin and mineral deficiency.
  • You may need to be on vitamin and mineral supplements following the surgery.
  • You may feel nauseous.
  • This may lead to low blood sugar.
  • It may cause inflammation, ulcer, and hernia.
  • You will have follow-up appointments with your doctor.
  • You may need to follow a strict and specific weight loss surgery diet.
  • A reoperation may be necessary.

Weight loss surgery may be the best option available if you are obese and/or suffer from life-threatening comorbidities. Talk to your doctor and do your research about which surgeon and hospital facility you want to have this procedure performed before you take the next step. Remember, this surgery is NOT recommended for individuals who have the ability to reduce their weight by healthy eating and exercising.

Back To TOC

Frequently Asked Questions

What is the success rate of weight loss surgery?

Weight loss averages 65% for most patients, with over 85% of patients losing and maintaining 50% of the initial excess weight loss.

Does weight loss surgery affect pregnancy?

You must talk to your gynecologist. Depending on the type of weight loss surgery, weight regain, current lifestyle, and medical reports, your doctor will tell you how it may affect your pregnancy.

Recommended Articles:

Was this article helpful?

PatrickMD, FACS

Dr. Patrick Hsu is a board-certified plastic surgeon and reconstructive microsurgeon with 10 years of experience. He is also the founder of Memorial Plastic Surgery. He was born and raised in Short Hills, New Jersey, and knew even as a young boy that he wanted to be a surgeon. The field of plastic surgery was a natural choice for Dr....read full bio

Latest Articles