Bariatric Surgery FAQ

Nausea After Gastric Sleeve Surgery

Nausea After Gastric Sleeve Surgery - Bariatric Fusion

The benefits of bariatric surgery are undeniable, but the transition to life after the procedure can come with numerous side effects.

Not only is nausea uncomfortable, but it can also interfere with adequate intake of fluid and electrolyte balance, resulting in more severe side effects.

Below is a review of common causes of nausea and tips on how to lessen this side effect of bariatric surgery.

What This Article Covers:

Common Causes of Nausea

Anesthetic and Surgery

Immediately after surgery, it is common to experience nausea and even vomiting. There are several causes of this after surgery.

Side effects from medication and sedation, as well as the anesthetic itself, can make you feel queasy, as can post-operative pain.

It is important that nausea does not progress to vomiting and possible damage to the surgery site. Your surgeon is likely to prescribe multiple medications to help prevent it.

Initial nausea should not last longer than a couple of days after surgery.

Medication and Vitamin Supplements

Some medications can cause nausea when taken on an empty stomach.

The changes in stomach acid can affect the rate at which vitamins and medications are absorbed, resulting in irritation of the stomach lining.

Taking your medications with meals or trying different forms of supplements, for example, liquid supplements or chewable bariatric vitamins, may help prevent nausea after gastric sleeve surgery.


Dehydration after bariatric surgery is a potential risk.

You must keep in mind that your stomach size is significantly reduced and can be easily overfilled. Drinking too fast or drinking while eating food can put pressure on the new stomach pouch and lead to nausea.

Most healthcare providers recommend pacing yourself and waiting at least 30 minutes after a meal before having a drink.

Advancing Stages Too Soon

Many people are tempted to consume solid food too soon after weight loss surgery.

There is a good reason that reintroducing food in stages of quantity and texture is recommended.

Adjusting to a new way of eating takes patience, but rushing to eat solid food will result in difficulty processing the food and cause nausea.

Dumping Syndrome

nausea after gastric bypass surgery

Dumping syndrome is a condition that can develop after bariatric surgery when food moves from the stomach into the small intestine too quickly.

This unpleasant side effect can happen within minutes of eating a meal or even hours after.

Signs of dumping syndrome include abdominal fullness, cramping, nausea, sweating, and dizziness.

Consuming high sugar foods is the biggest culprit, so stick to eating guidelines that your medical team provides you.

Food Intolerances

Temporary food intolerances can develop after gastric bypass surgery; the changes in acidity, enzymes, and hormones involved in digestion need time to normalize.

Food intolerances differ from person to person, but research has found that non-essential high sugar and high-fat foods cause the most trouble resulting in nausea.

Try small amounts of individual foods at a time. This will help you determine which foods are problematic.

Eating Too Quickly

Eating too fast increases the chance of nausea.

The general recommendation is to eat slowly, taking at least 30 minutes to eat a meal. Of course, this depends on what is being consumed and how far out from surgery you are.

Eating with smaller utensils serves as a reminder to take your time and can slow eating.

Chewing Food

It is required to chew thoroughly to a paste consistency after bariatric surgery. Chewing cannot be emphasized enough after bariatric surgery.

Proper chewing gives the stomach time to message the brain that it is full and prevents large pieces of food from getting stuck.


Initially, it may be difficult to gauge how much food you can eat at one time.

Overeating is one of the most common causes of nausea after surgery. Measuring out portion sizes when you prepare meals is essential.

If you are not sure of portion sizes, consult your dietitian for guidance.

Lying Down Too Soon After a Meal

Acid reflux or burping after bariatric surgery can be worsened by lying down too soon after a meal. This increases the chance of feeling nauseous.

Give your food a chance to digest and wait at least an hour after a meal before lying down.


Abdominal surgery can result in scarring in the abdominal cavity. This scarring is called adhesions and can cause twisting of the intestine and blockage.

A blockage is a rare side effect, but it can occur even years after surgery. Nausea and abdominal pain can be common symptoms.

Frequent nausea and vomiting should always be reported to your doctor.


Some patients may develop stomach ulcers after bariatric surgery. These can commonly form at the new connection between the new stomach and the small intestine.

Smoking and taking aspirin or anti-inflammatory medication will increase your risk of developing ulcers.


A stricture occurs when scar tissue develops at the joint of the new stomach and small intestine, making the opening smaller than it should be.

A stricture obstructs the passage of food and can cause nausea and vomiting. Stricture is a bariatric surgery long-term side effect, but it can be corrected by your surgeon dilating the connection with a special balloon catheter.

Will Nausea Improve With Time?

Healing from gastric sleeve surgery takes time and patience.

nausea after bariatric surgery

As you understand your new dietary needs and get used to new eating habits, issues with nausea will subside.

Many causes of nausea following bariatric surgery can be avoided if you diligently adhere to guidelines the surgeon provides you.

What if Nausea Persists?

Recurring nausea months, or even years, after gastric bypass is uncommon, but can occur. Always consult your bariatric surgeon or doctor so they can investigate. This will rule out any serious health issues that might be causing nausea.

Bottom Line

Experiencing nausea is common after weight loss surgery, but largely preventable by following your surgeons’ guidelines.

Be mindful of what and how you eat, get adequate rest, and address stress and anxiety. Psychological stress can cause nausea too.

Please keep in mind that these are just a few tips on the causes and prevention of nausea.

If you do experience persistent nausea, pain, or uncommon side effects, contact your healthcare provider immediately.

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**This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your physician or another qualified health provider with any questions in regards to a medical condition. A qualified healthcare professional can best assist you in deciding whether a dietary supplement is suitable based on your individual needs.

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