Hypoglycemia may occur after gastric sleeve surgery, especially if you’ve eaten foods high in sugar or fat.

Gastric sleeve surgery is becoming a more common method for some people to lose weight, especially for those with type 2 diabetes when eating habits, exercise, and lifestyle changes are not enough.

Although gastric sleeve surgery can have positive health results, it also carries risks that include postsurgery hypoglycemia.

Hypoglycemia, or low blood sugar, is rare in people who do not have diabetes. However, it may occur after gastric sleeve surgery due to quicker passage of food through the stomach into the intestines.

Following a specific diet and taking medications to lower insulin levels after eating can help prevent hypoglycemia, but when it does occur, treatment with glucose or glucagon is necessary.

Dumping syndrome is frequently the cause of hypoglycemia after gastric sleeve surgery. It occurs when food moves too quickly from the stomach to the small intestine. Approximately 10% of people who have stomach surgery will develop it, according to the National Institute of Diabetes and Digestive and Kidney Diseases.

Dumping syndrome can cause hypoglycemia because when food moves too quickly from your stomach to the intestines, the digestive tract releases higher levels of hormones than it normally would. Fluid also moves to your small intestines from the bloodstream.

The pancreas responds to the higher hormone levels by creating more insulin than is necessary. Too much insulin can then lead to low blood sugar approximately 1 to 3 hours after eating.

Even if you have recently had gastric sleeve surgery, doctors will still need to rule out other potential causes of hypoglycemia because the low blood sugar levels are not always due to dumping.

Common symptoms of low blood sugar include:

  • hunger
  • headaches
  • dizziness
  • fatigue
  • blurry vision
  • sweating
  • shaking or trembling
  • pale appearance
  • trouble concentrating or remembering

Severe cases of hypoglycemia may result in seizures or coma.

Preventing post-bariatric hypoglycemia involves eating only approved foods and taking medications to reduce insulin production.

If you do develop hypoglycemia, it should be treated immediately with glucose or glucagon.

For acute hypoglycemia, taking glucose tablets or gel and then waiting 15 minutes to see if your blood sugar level rises can be an effective way to reregulate blood sugar.

For more severe hypoglycemia, glucagon and intravenous (IV) medical treatment may be necessary to raise your blood sugar level.

After regulating your blood sugar level, the underlying cause should be identified and treated. In many cases, post-bariatric surgery hypoglycemia is due to dumping syndrome and can be prevented in the future by changing how frequently you eat as well as what you eat.

In some cases, medications can also help.

Octreotide and acrabose have both been prescribed to treat this condition.

It’s important that you avoid sugar after gastric sleeve surgery because it can lead to dumping syndrome. (When foods with sugar are dumped quickly into the intestines, it can lead to abdominal cramping, nausea, diarrhea, dizziness, and fatigue in addition to hypoglycemia.)

In addition to avoiding sugar after gastric sleeve surgery, it is recommended to avoid high fat foods and enjoy water between meals versus during meals. Right after surgery, you can expect to consume only clear liquids. This will typically advance in a couple of days to other liquids that do not contain sugar and that are low in fat (ex. skim milk).

You will graduate from liquids to a pureed diet next, but you should continue to avoid seedy fruits and vegetables as well as foods like cauliflower and broccoli that are very fibrous and do not liquify well.

When doctors feel that recovery has progressed sufficiently, they’ll allow the introduction of soft solids. When solid foods are approved, it’s important that you eat slowly, thoroughly chewing before swallowing.

Research has found that low carbohydrate, high protein meals are less likely to lead to hypoglycemia after bariatric surgeries. Meals should ideally be consumed 3–4 hours apart and not include alcohol or caffeine. It’s also important that you take any vitamin and mineral supplements your doctor may recommend.

Although hypoglycemia is rare for people who do not have diabetes, it can occur after gastric sleeve surgery.

If you have gastric sleeve surgery, it’s important to stick to your medically approved meal plan to help prevent dumping syndrome, which can lead to hypoglycemia. Even when a strict diet is maintained, it’s possible to experience hypoglycemia after gastric sleeve surgery.

So if you are planning on having gastric sleeve surgery, you may wish to talk with your doctor about how to treat potential hypoglycemia if it should occur with glucose or glucagon.