Bariatric surgery side effects

Common Bariatric Procedures and Their Side Effects

Side effects are a common concern for patients who have undergone weight loss surgery. Some side effects can be expected regardless of which surgery you decide to get. However, some surgeries can make you more prone to specific symptoms such as ulcers. Informing yourself about the potential adverse effects of weight-loss surgeries can better help prepare you for a much better outcome.

Here are three of the most sought-after surgeries that we performed in 2021, including the gastric sleeve, RNY gastric bypass, mini-gastric bypass, and duodenal switch. Each procedure explicitly targets a patient’s weight loss needs and goals. Depending on their health, some surgeries could be recommended over others. We will break down each procedure and identify common side effects based on a survey collection of over 1000 patients from 2021.

Gastric Sleeve (887/1,116)

A gastric sleeve is primarily a restrictive metabolic procedure that helps accelerate weight loss. It’s achieved by laparoscopically removing 80% of the stomach’s greater curvature, permanently reducing the ghrelin hormones present. This procedure is a solid base surgery that can easily be revised and transitioned into another weight-loss method if needed.
Most Common Side Effects After Gastric Sleeve Surgery

Top 5 Side EffectsPercentage
1. Hair loss60.99%
2. Constipation39.23%
3. Fatigue35.51%
4. Gas33.60%
5. Vomiting26.38%

RNY Gastric Bypass (132/1,116)

RNY Gastric Bypass uses both restriction and malabsorption methods to aid weight loss. The restriction is achieved by forming the new “egg-sized” stomach pouch, the stoma, measuring roughly 5-10% of the original stomach. The stoma is separated from the stomach while the remaining stomach stays intact to help digestion. Malabsorption is caused by the rerouting, or “bypassing,” of the intestines causing fewer calories and nutrients to be absorbed.
Most Common Side Effects After RNY Gastric Bypass Surgery
Top 5 Side EffectsPercentage
1. Gas60.61%
2. Hair loss58.33%
3. Fatigue42.42%
4. Nausea37.12%
5. Diarrhea35.61%

Mini Gastric Bypass (47/1,116)

The mini-gastric bypass shares a similar combination of restriction and malabsorption but with a slight twist. The stomach is cut similarly to the gastric sleeve, leaving 15-20% of the stomach. It is medically considered a modification of RNY gastric bypass due to its single anastomosis (one connection) of the intestines. About two meters of the small bowel is removed and is re-connected between the small intestine and new stomach pouch.
Most Common Side Effects After Mini Gastric Bypass Surgery
Top 5 Side EffectsPercentage
1. Hair loss61.70%
2. Gas59.57%
3. Bloating40.43%
4. Fatigue38.30%
5. Nausea36.17%

DS-Duodenal Switch (50/1,116)

The Biliopancreatic Diversion with Duodenal Switch (BPD/DS), or simply Duodenal switch (DS), is known as the most powerful metabolic and bariatric surgery that combines two of the most popular weight loss procedures; the gastric sleeve and RNY gastric bypass. Sleeve gastrectomy is responsible for removing 70% of the stomach and transforming it into a “sleeve”. This restrictive technique causes the new stomach to have fewer hunger hormones (ghrelin) while minimizing the amount of food it can hold. The malabsorption approach requires rerouting the intestines by bypassing the small intestine’s duodenum and jejunum to help diminish the absorbed nutrients. This modification disrupts the standard process for the breakdown of food from digestive juices and bile, causing fewer calories to be consumed.
Common Side Effects After Duodenal Switch Surgery

Top 5 Side EffectsPercentage
1. Diarrhea66.00%
2. Fatigue46.00%
3. Dehydration26.00%
4. Vomiting18.00%
5. Constipation18.00%


Bariatric surgery can have its fair share of side effects, but some of them share specific ones across the board. Hair loss is one of the main side effects many patients face due to the drastic diet changes, accelerated weight loss, and choice of weight loss surgery. Hair loss is temporary until your body can adjust to the new diet and lifestyle. Another common side effect is gas, mainly caused by the foods digested. Ways to find relief could be from over-the-counter treatments like Gas-X, or simply walking around could help alleviate it. The final similar by-product of weight loss surgery is fatigue. Your body has been shocked by a new process of retaining and breaking down food that can demand an entire reboot of your body’s digestive system. Give your body plenty of time and rest before you start to embrace the new lifestyle fully.

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