Health Information Library

All the content of the library is provided from Mayo Clinic in English.
As a member of the Mayo Clinic Care Network, RSPP has special access to Mayo Clinic knowledge and resources.

< Back

Reactive hypoglycemia: What can I do?

Answer Section

Hypoglycemia is the medical term for low blood sugar. Reactive hypoglycemia, sometimes called postprandial hypoglycemia, happens when blood sugar drops after a meal — usually within four hours after eating.

Symptoms of hypoglycemia may include:

  • Shakiness.
  • Dizziness or lightheadedness.
  • Sweating.
  • Hunger.
  • A fast or uneven heartbeat.
  • Feeling weak or tired.
  • Feeling irritable or anxious.
  • Headache.
  • Confusion.

In people who have diabetes, insulin or other medicine that's used to lower blood sugar sometimes can lead to hypoglycemia after eating. A change to the medicine dosage may help.

In people who don't have diabetes, the cause of reactive hypoglycemia often isn't clear. But symptoms may be connected to what and when a person eats.

Other possible causes of reactive hypoglycemia include:

  • Alcohol.
  • Some surgical procedures, such as gastric bypass or other bariatric surgery.
  • Metabolic conditions that are passed down in families, also called inherited metabolic disorders.
  • Certain types of tumors.

A medical evaluation usually is done to see if symptoms are caused by low blood sugar, and if so, whether symptoms get better when blood sugar returns to normal. More testing may be needed if symptoms are severe.

Reactive hypoglycemia usually doesn't require medical treatment. But if another health condition is causing it, that condition needs to be treated. The following diet changes may help ease symptoms:

  • Eat a balanced diet that includes high-fiber foods, such as whole grains, fruits and vegetables.
  • Avoid sugary foods and processed simple carbohydrates, such as white bread or white pasta, especially on an empty stomach.
  • When drinking alcohol, eat food with it.
  • Eat several small meals and snacks about three hours apart throughout the day.
  • Exercise on a regular basis.

Content Last Updated: 13-Apr-2023
© 1998-2023 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of Use.