Bad Breath after Gastric Sleeve Surgery | Gastric Bypass Surgery

bad breath post gastric sleeve surgery

Bariatric surgery is one of the most effective ways to lose weight for people with morbid obesity or chronic weight-related complications. According to research, most individuals who undergo this procedure rarely have regrets afterward.

Except for one thing, bad breath.

Foul-smelling breath is one of the nastiest side effects of bariatric surgery. But should it deter you from taking the procedure? And if you’re already battling it, how do you deal with it effectively? Let’s break these down.

What Causes Bad Breaths After Bariatric Surgery?

Bad breath is a side effect of gastric sleeve and gastric bypass surgeries. However, it is less common with gastric sleeves compared to gastric bypass. It is very rare to suffer from bad breath after gastric sleeve surgery.

Bad breath for gastric sleeve surgery patients often occurs due to several factors such as stasis, stomach problems, and change in diet. The most common reasons behind bad breath after gastric sleeve surgery include:

  • Smoking
  • A high-protein diet (Ketosis)
  • Acid reflux (GERD)
  • Indigestion and other stomach problems
  • Too much sugar and alcohol
  • Dehydration
  • Food stuck in the digestive tract (stasis)
  • Poor oral hygiene

In most cases, eating a low-sugar, low-acidity diet and drinking plenty of water prevents bad breath. However, there are other causes you might want to pay close attention to.

Stasis and GERD

Bariatric surgery works by shrinking the stomach. This sudden reduction in volume often makes it difficult for food to move through the digestive tract. When this food gets stuck, it can cause acid reflux. Consistent acid reflux leads to gastroesophageal reflux disease, GERD.

As the undigested food, bile, or stomach acid backflows towards your mouth, it causes bad breath plus some pain.

Stasis and GERD can be treated using over-the-counter drugs and prescription medication which will help reduce the frequency and severity of the condition.

Stasis and GERD also eventually calm down as you get more accustomed to your new stomach and develop ways of naturally keeping the symptoms and smell away.


The body goes into the state of ketosis when it uses fats instead of carbohydrates for energy. This is the goal for bariatric surgery and is one of the primary reasons you’ll lose weight quickly.

As the body undergoes ketosis, it releases ketones that contain acetone. Acetone releases a fruity odor which some may find offensive or foul.

bad breath side effect gastric sleeve

The Other Side Effects of Ketosis

Bad breath often starts a few days after surgery. This normal body reaction as it adjusts to its new diet also comes with the following effects:

  • Body odor: It’s common to have increased body odor during ketosis. Your body adapts with time, with the odor decreasing and stabilizing after one to four months.
  • Dry mouth: Dry mouth occurs because of reduced carbohydrate and sodium intake. Hydrating helps prevent dry mouth and bad breath.
  • Metallic taste: A metallic taste in the mouth after surgery is common. It takes two to eight weeks to dissipate.
  • Insomnia: Glucose keeps our bodies constantly energized and elevates the serotonin levels in the brain, which helps the body relax and sleep. During ketosis, glucose is very low, which may trigger insomnia.
  • Digestive issues: Ketosis often triggers constipation, gas, and diarrhea. This is due to the lack of fiber which a healthy digestive system needs. High-fiber foods and carbohydrates prevent constipation. To reduce digestive issues, you can eat low-carb high-fiber foods such as broccoli, cauliflower, and avocados.


Dehydration is often treated as a direct symptom of gastrectomy. It’s caused by patients forgetting to drink enough fluids due to the new diet restrictions. Feeling fuller for longer or taking smaller spaced-out sips deters most patients from staying hydrated.

Staying hydrated helps rinse out odor-inducing bacteria and keep the body functioning optimally.

How Long Does the Body Take to Adapt?

It may take weeks to a few months for the body to fully adapt to the new diet, reduce ketosis, and improve foul breath. It may be difficult to control the bad breath during this period, but practicing good hygiene can make a huge difference.

Once your body has adapted to the new diet, it will efficiently process fats from its byproducts.

Tips to Deal with Bad Breath After Bariatric Surgery

The following are what you can do to deal with bad breath after bariatric surgery:

  • Drink lots of water
  • Chew sugar-free gum that stimulates the production of odor-fighting saliva
  • Brush and floss after every solid or liquid meal. Don’t forget the tongue since it can harbor odor-generating bacteria and food particles on the surface
  • Use a water pick to clean out food particles more thoroughly
  • Try cinnamon-flavored gums
  • You can also visit a dentist to rule out tooth decay or gum disease

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