Gastric bypass vs gastric sleeve: which one is better for you?

If you’re considering weight loss surgery, you may be wondering which procedure is right for you. Two of the most popular options are gastric sleeve and gastric bypass surgery. 

While both surgeries aim to help you lose weight, they differ in terms of their approach and the specific benefits and risks associated with each procedure. While patients can share their preferences with their doctor, it’s ultimately up to the doctor to determine which surgery is best suited for the patient’s individual needs and health condition. 

In this article, we’ll explore the key differences between gastric sleeve vs gastric bypass surgery, so you can get a hint about which option is more suitable for you.

What's the difference between gastric bypass and gastric sleeve?

gastric sleeve vs gastric bypass

The difference between gastric bypass and gastric sleeve is based on their techniques, requirements, results, and post-op diet stages.

In terms of techniques, they differ in the size of the stomach, the bypass has a small pouch and the gastric sleeve stomach is tube-shaped.

Nevertheless, due to the differences in techniques, the results differ in terms of portions of food eaten, the amount of losing weight, and food tolerance. 

The difference in requirements

There is common ground between the gastric sleeve and gastric bypass procedure but there are a few differences in requirements, let’s point each one out.

BMI: Generally, a gastric sleeve is an option for 35+ BMI patients. However, gastric bypass surgery is more suitable with 40+ BMI

Health condition: If the patient has many obesity-related diseases, such as type 2 diabetes, the doctor is most likely to suggest bypass surgery.

Post-op diet: Each surgery requires a specific 5-stage pre-op diet to reduce any surgical complications. For gastric bypass, the durations of the stages are a bit longer.

The difference in procedure and techniques

The gastric sleeve procedure as known as sleeve gastrectomy procedure involves removing more than half of the stomach, leaving a banana or tube-shaped passage between the esophagus and duodenum. This helps with the portion of food intake and causes manipulation of a hunger hormone and ghrelin which helps to lose excess body weight. It is known as laparoscopic surgery although it has other ways to be performed in other ways as well.

Gastric bypass aka Roux-en-Y is also laparoscopic surgery. The procedure involves creating a small pouch of the stomach and rerouting it straight with the smaller intestines. This results in a small passage for the food with very limited calorie absorption. This procedure is more complex than gastric sleeve surgery and more recovery time is needed.

The difference in results

Physical appearance, changes in weight loss, and health improvement vary because of factors such as starting weight, age, and medical history. Both gastric sleeve and bypass show remarkable results in patients and the success rates are very high, patients leave with positive feedback in the long-term results.

Gastric sleeve and gastric bypass aim to lose 50 to 60 percent of the weight in a year and a half, but the difference in weight loss is that bypass patients might lose more weight in a shorter period of time. 

Losing weight helps to improve health and is a solution for obese-related diseases such as blood pressure and sleep apnea. However, gastric sleeve affects less extensively with type 2 diabetes, but gastric bypass remission rates reach up to 80%. (1)

The difference in post-op diet

Bariatric surgeries aim to help the patient to follow a diet and feel full after a small portion of food intake. The gastric bypass is only 1 oz., it is almost the size of a golf ball. Due to less absorption of calories and nutrition in bypass patients, there is a high possibility of having nutritional deficiencies at the beginning of the diet. The patients need to take vitamins and mineral supplements for 3 to 6 months. Whereas gastric sleeve patients are less likely to take the supplements because the stomach size is 4-5 oz. (2)

The stages are: 

  • Clear liquid: First 2 days patients have only clear liquids like water, broth, etc.
  • Full liquid diet: This diet contains only a clear liquid diet to help the stomach heal.
  • Soft & Pureed diet: After clear liquids, patients can have mushed food and include soft food in their diet, such as scrambled eggs.
  • Solid diet: Patients can start including meat, fresh veggies, and fresh fruits in their diet. 
  • Maintenance diet: This diet is only guided to bypass patients and it aims to monitor the food intake that must be complemented with vitamin supplements to prevent nutrient deficiencies 

Durations of the stages are: 

Diet typeGastric sleeveGastric bypass
Clear liquidDays 1-2Days 1-2
Full liquidDays 3-7Weeks 2-3
Soft & Pureed foodWeeks 2-3Weeks 4-6
Solid foodWeeks 4 and beyondWeeks 6-8
Maintenance Week 9 and beyond

Overall, the postoperative diet for both gastric surgeries will require a lifelong commitment to healthy eating and portion control. Patients should work closely with their healthcare provider and a registered dietitian to develop a customized diet plan that meets their individual needs and helps them achieve a healthy weight.

If you need more detailed informations here’s two options:

Which is safer, gastric sleeve or bypass?

In terms of safety, both bariatric procedures are secure. This all goes to the technicalities and in hands of the surgeon and their experience in the field. However, even though the possibility is very rare, gastric bypass surgery has a more complicated and invasive approach which increases the risk and complications, such as leakage or infection.

That being said, in terms of which is more successful gastric bypass or sleeve for you depends on your medical history, current health status, and weight loss goals play major roles in terms of safety.

Your doctor will consider the safest surgical option for you and provide you with information.

Which is better gastric bypass or sleeve?

If you wonder what is the benefit of having a gastric sleeve vs gastric bypass, then Both surgeries are common and have great feedback from both doctors and patients for their affection for losing excess weight. However, they differ in many outcomes, such as:

gastric sleeve vs gastric bypass pros and cons

Complexity & Risk: Gastric bypass surgery is a more complicated surgery and has potential complications.

Recovery time: Due to surgical complexity gastric bypass requires more hospital stay and more recovery time.

Lack of efficiency: Gastric bypass patients are required to have minerals & vitamin supplements to maintain a high quality of life for 3-6 months.

Variety of diet: Gastric sleeve patients can go back to a regular diet in the long run.

Thyroid hormone: studies show both of the surgeries help control thyroid hormone levels but it needs to be monitored. You will still need to take meds to balance the hormones; hypothyroidism (underactive thyroid) is increased and lowers TSH (thyroid stimulating hormone). (3)

Type 2 diabetes: Gastric bypass is considered a metabolic surgery because it regulates glucose and insulin levels. This is due to the direct connection to the smaller intestines which manipulates the hormones and have less food consumption. It leads to a greater reduction in blood sugar levels and a higher rate of remission of type 2 diabetes compared to gastric sleeve

Reversibility: Reversing the surgery is possible. Yet, it is a very rare operation due to its risk and complications. Most surgeons do not approve and perform this operation.

In conclusion, which is more successful gastric bypass or sleeve? None of them is better than the other, but one option is more suitable than the other depending on your case. The doctor decides what is best for you in the end. 

How does your doctor decide the best one for you?

When it comes to deciding whether a patient should undergo gastric sleeve or gastric bypass surgery, the doctor will take several factors into consideration. One of the most important factors is the patient’s weight loss goals. If a patient has a significant amount of weight to lose, gastric bypass may be the better option. Additionally, the patient’s overall health, any pre-existing conditions, and surgical history will also be taken into account. Ultimately, the doctor’s top priority is ensuring the patient’s safety and helping them achieve their weight loss goals in the most effective way possible.

Weight loss goals: For patients with a BMI of 40 or higher who are seeking significant weight loss, gastric bypass may be a more suitable option than the gastric sleeve.

Overall health: If you have type 2 diabetes with a history of acid reflux, the doctor recommends bypass for its effectiveness. Even though a gastric sleeve helps with diabetes, a gastric bypass has more advantages to it and a chance to cure it.

Surgical history: If you have undergone stomach-related surgeries previously, such as gastric banding or sleeve gastrectomy, your doctor is more likely to suggest gastric bypass for you. In this case, the surgery is called revision because it could be done in case you reach the point where are not able to lose more weight. Your revision could be a gastric sleeve to bypass or a mini bypass. (4)

The decision that the doctor comes up with is based on the priority of making you a healthier person to have a better quality of life.


(1) Castellana M, Procino F, Biacchi E, et al. Roux-en-Y Gastric Bypass vs Sleeve Gastrectomy for Remission of Type 2 Diabetes. J Clin Endocrinol Metab. 2021;106(3):922-933. doi:10.1210/clinem/dgaa737 Link


(3) Rudnicki Y, Slavin M, Keidar A, et al. The effect of bariatric surgery on hypothyroidism: Sleeve gastrectomy versus gastric bypass. Surg Obes Relat Dis. 2018;14(9):1297-1303. doi:10.1016/j.soard.2018.06.008 Link

(4) Keleidari B, Mahmoudieh M, Shahabi S, et al. Reversing One-Anastomosis Gastric Bypass Surgery due to Severe and Refractory Hypoalbuminemia. World J Surg. 2020;44(4):1200-1208. doi:10.1007/s00268-019-05290-7 Link

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