Understanding Reactive Hypoglycemia: All You Need to Know

Reactive hypoglycemia occurs when your blood sugar is after a meal, but when should you start to worry if this condition is a sign of more serious issues? Find out symptoms, causes, prevention tips, and more.

Mia Barnes
— Signos
Staff Writer
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Reviewed by

Mia Barnes
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Updated by

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Science-based and reviewed

April 23, 2024
June 19, 2023
— Updated:

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You ate breakfast, but come 11 a.m., you feel nauseous, shaky, and dizzy. You might have even developed a mild headache. What’s going on? Did you fail to eat enough, is it a normal dip in your glucose levels, or could you have reactive hypoglycemia? 

This medical condition can affect you like a case of the flu, but it’s readily treatable and preventable. Knowing what it is and what to do brings rapid relief. However, you can suffer adverse effects if you ignore this condition, as severe hypoglycemia could be an indication of a serious medical conditions, such as pre-diabetes. Here’s all you need to know about reactive hypoglycemia. 

What is Reactive Hypoglycemia?

Hypoglycemia is a fancy scientific word for low blood sugar. You might be familiar with the term if you or someone you love is living with type 1 or 2 diabetes. Keeping your glucose levels within the desirable range is vital to reducing your risk of serious health complications, such as heart and kidney disease and blindness1.

There are two types of hypoglycemia you should know about:

  • Reactive hypoglycemia: Also called postprandial hypoglycemia, this type occurs after eating, typically within four hours of a meal. 
  • Fasting hypoglycemia: This type occurs after going without eating for eight hours or more. Low fasting blood sugar indicates an elevated diabetes risk. 

It’s a snap to tell what type affects you; ask yourself when you last ate.

Your pancreas is your insulin-producing organ, which also helps you maintain the ideal balance.2 Trouble with this organ can result in type 1 diabetes or type 2 diabetes.

If you currently take medication to manage diabetes, recurring symptoms could indicate a need to adjust your doseage. Talk to your doctor about your options and specific situation. 


Signs and Symptoms of Reactive Hypoglycemia 

This health condition isn’t shy, manifesting in multiple unpleasant symptoms. It can make you feel worse than a case of the flu, although your agony won’t last nearly as long if quickly addressed. 

When should you suspect reactive hypoglycemia? Here are some common symptoms you can expect. 

Common symptoms

  • Fatigue: Do you get walloped with the need to nap an hour or so after lunch, so much so that you can barely keep your eyes open? It could be reactive hypoglycemia.
  • Dizziness
  • Anxiety
  • Shaking
  • Increased appetite: You could crave carbohydrates in particular. 
  • Headaches and migraines: If you always get walloped two hours after lunch, your blood sugar could play a role.
  • Poor concentration
  • Nausea
  • Increased heart rate: This is one of the more frightening symptoms. It can also contribute to anxiety, as your body interprets your racing heart as panic. 

These symptoms typically develop within two to three hours after a meal. Fortunately, they’re easily correctable. However, other symptoms can be more severe, requiring medical intervention. 

Severe symptoms

  • Confusion: You might forget what day it is or what you should be doing. 
  • Behavioral changes: Mild hypoglycemia can make you irritable, but more severe cases can leave you belligerent. 
  • Clumsy movements: You might find walking in a straight line hard or lose coordination. 
  • Blurry or altered vision: Things could get hazy or appear surreal. 
  • Seizures: One of the most dangerous symptoms, causing loss of control over your muscles. 
  • Loss of consciousness: This symptom nearly always requires medical intervention. 

These symptoms are dangerous because they affect your ability to carry out your daily tasks. Furthermore, they could be symptoms of a more serious underlying health condition. For example, blurry vision, behavioral changes, and clumsy movements can also indicate a stroke, a medical emergency requiring rapid intervention to prevent or minimize permanent brain damage⁴.

Treatment for reactive hypoglycemia typically involves eating a specific food item. For example, if you live with diabetes, you should follow the direction given by your doctor. Suggestions could include consuming 15 grams of carbohydrates and testing your blood sugar to see if it has recovered to an optimal range. Repeat until your blood sugar reaches 70 mg/dL.3 If you do not live with diabetes, simply snack until you feel better. 

When to See a Doctor

You should see a doctor for reactive hypoglycemia under three conditions: 

  • You develop severe symptoms: If you experience any of the symptoms listed as severe, you should seek medical attention. 
  • You live with diabetes, and episodes happen often: If you have more than one such episode per week, talk to your doctor. They may need to adjust your dosage. 
  • You live with diabetes, and carb-laden snacks don’t help: If you drink sugary foods, such as juice, but your symptoms continue, please seek medical care. 

Causes of Reactive Hypoglycemia 

Doctors often can not immediately identify reactive hypoglycemia causes without further testing if you are non-diabetic. Non-diabetic hypoglycemia can result as a side effect of some health conditions or the following: 

  • Foods with a high glycemic index: Some foods, like candy, raise your blood glucose levels too rapidly, followed by a debilitating crash. 
  • Gastric bypass surgery: This type of stomach surgery shrinks your stomach size, requiring you to eat smaller meals that may not tide you over for several hours. Ulcer surgery can have a similar effect.
  • Metabolic disorders: Some conditions affecting your adrenal or pituitary gland can cause hypoglycemic symptoms. The deficiency of certain digestive enzymes can also interfere with the body's ability to break down food, which reduces the amount of glucose available for absorption in the intestines. 
  • Tumors: A pancreatic tumor can result in reactive hypoglycemia.

Most cases of reactive hypoglycemia occur for unidentifiable reasons and do not indicate serious health risks. However, only your doctor can make that determination.

Diagnosis & Treatment

Your doctor will perform several tests to determine the underlying cause of your reactive hypoglycemia symptoms. Your healthcare provider will likely start with a mixed-meal tolerance test (MMTT). During the MMTT, you will drink a sugary drink that will raise your blood sugar and cause your body to make more insulin. Your healthcare provider will then check your blood sugar levels over the next few hours.6 Your doctor will perform additional diagnostic testing if blood sugar isn’t the underlying issue. 

Reactive hypoglycemia treatment typically consists of eating something to stabilize your blood sugar. A candy and a filling snack like a low-sugar protein bar should quickly improve how you feel. 

What to Eat During an Episode

If you notice reactive hypoglycemia symptoms, you should turn to fast-acting carbohydrates that raise your blood sugar. Here’s a short list of some good ones to keep on hand: 

  • Banana
  • Honey
  • Glucose gel
  • Fruit juice
  • Raisins
  • Milk
  • Sugar
  • Syrup
  • Hard candies 

Consider following up with a protein and whole-grain snack, like peanuts and seeded crackers. This combo helps stabilize your blood sugar, preventing future reactive hypoglycemic symptoms.

The foods at mealtime also affect whether or not you develop reactive hypoglycemia symptoms. How can you prevent it from occurring in the first place? 

How to Prevent Reactive Hypoglycemia

The best way to tackle reactive hypoglycemia symptoms is prevention and embracing specific lifestyle changes. The following tips can minimize your risk. 

1. Adopt a healthy and balanced diet

The best diets consist of whole foods that resemble their natural forms. To thrive, you need a balance of lean proteins, fruits, vegetables, and healthy fats. Doctors may recommend making dietary changes or adopting certain eating styles like the Mediterranean Diet. Below are some general dietary recommendations to keep in mind:5 

  • Balance your omega-3 and omega-6 fatty acids: You need both omega-3 and omega-6 fatty acids for health, but the problem is the proportion.9 Omega-6s increase in vegetable oils, like the safflower, sunflower, canola, soybean, and corn oil used in many prepared foods. You can find omega-3s in fatty fish, eggs, and seeds like chia and flax. 
  • Stick to whole grains: You should watch your carbohydrate intake if you’re prone to reactive hypoglycemia symptoms. However, whole grains absorb slowly because of their filling fiber and don’t cause huge fluctuations. Avoid processed simple carbohydrates, such as white bread or white pasta.
  • Have protein with each meal: A combination of protein and whole-grain foods stabilizes your blood sugar, preventing spikes. 
  • Make fruits and vegetables the main course: Although many people make meat the centerpiece of their table, fresh veggies should predominate. Think of your plate as a clock, with a half hour for salad greens and cooked vegetables and 15 minutes each for starch and protein. 

2. Beware high glycemic foods

Avoid these two big baddies, eating them in moderation, if at all: 

  • Sugar: Refined sugar absorbs straight into your bloodstream, causing rapid fluctuations. 
  • Bleached flour: Your body treats this like sugar because manufacturers strip away the bran and chaff. What’s left behind is a fiberless goo that spikes your glucose. Unfortunately, it’s also found in many convenience foods, so read labels carefully. 

3. Eat less, more frequently

You might benefit from eating six small meals spaced throughout the day to prevent reactive hypoglycemia symptoms instead of two or three larger ones. 

4. Avoid alcohol and sugar mixes

Alcohol is high in sugar. Additionally, you should recognize these common terms for “added sugar” on food labels:

  • Fructose (like high-fructose corn syrup)
  • Maltose
  • Sucrose
  • Maltodextrin
  • Agave nectar
  • Brown rice syrup
  • Corn syrup
  • Molasses
  • Barley malt
  • Evaporated cane syrup

5. Limit or avoid caffeine

Caffeine can increase gut motility, which speeds digestion, impacting blood sugar levels.7 Also, injesting caffeine or alcohol or an empty stomach, as this will significantly impact your blood glucose levels. 

6. Exercise regularly

Exercise keeps levels of various hormones in check. It teaches your muscle cells to use insulin and glucose more effectively, helping you balance blood sugar naturally. A lack of physical activity lowers insulin sensitivity, increasing your risk of reactive hypoglycemia symptoms and type 2 diabetes.

7. Manage stress

Stress causes elevated cortisol levels. This stress hormone can increase food cravings as your body interprets the excess as an ongoing threat it needs to fuel itself against. Worse, you typically desire high-sugar, high-fat meals. 

Can Hypoglycemia Be Dangerous?

If you are prone to reactive hypoglycemia symptoms, please don’t dismiss your disorder as inconvenient. While an occasional bout that you quickly correct won’t cause lasting harm, you may run a greater risk of developing type 2 diabetes.8 

Therefore, you should regularly use the above prevention tips. They can keep your reactive hypoglycemia symptoms at bay while lowering your type 2 diabetes risk. Millions of Americans don’t know they’re in danger, but your body is warning you; please heed it. 

Learn How to Improve Your Health and Monitor Your Blood Sugar Levels with Signos’ Expert Advice.

Everyone’s body is different, and you may need to try various techniques to ease your reactive hypoglycemia symptoms. As you implement the above dietary suggestions, you can find out how specific foods affect your blood sugar by tracking your glucose response using Signos.

Signos uses a CGM to gather your biodata and provides real-time feedback on how your body responds to different foods. The Signos app will suggest small changes in your activities or eating habits to reduce glucose spikes.

Learn more about Signos, their options, and pricing

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Topics discussed in this article:


  1. Manage Blood Sugar. CDC. Retrieved April 5, 2023 from: https://www.cdc.gov/diabetes/managing/manage-blood-sugar.html#:~:text=It%27s%20important%20to%20keep%20your,improve%20your%20energy%20and%20mood.
  2. What Does Your Pancreas Do? Dr. Mark Fraiman, MD, MBA. Retrieved April 5, 2023 from https://liverandpancreassurgeon.com/what-pancreas-does/
  3. What Is Reactive Hypoglycemia? WebMD. 2021. Retrieved April 5, 2023 from  https://www.webmd.com/a-to-z-guides/reactive-hypoglycemia
  4. Why Getting Quick Stroke Treatment Is Important. American Stroke Association. Retrieved April 5, 2023 from https://www.stroke.org/en/about-stroke/types-of-stroke/is-getting-quick-stroke-treatment-important#:~:text=Quick%20Stroke%20Treatment%20Can%20Save,stroke%20and%20even%20prevent%20death.
  5. Mediterranean Diet Ranked Best Diet Six Years in a Row: Is It Right For You? Medical News Today. Retrieved April 5, 2023, from https://www.medicalnewstoday.com/articles/best-diet-2023-us-news-ranking-mediterranean-dash
  6. Mixed Meal Tolerance Test. Cincinnati Children’s Hospital. Retrieved April 6, 2023 from https://www.cincinnatichildrens.org/health/m/mixed-meal-tolerance-test
  7. Effect of Coffee And Its Components on the Gastrointestinal Tract and the Brain-Gut Axis. National Institutes for Health. Retrieved April 6, 2023 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824117/
  8. Postprandial Reactive Hypoglycemia. National Institutions for Health. Retrieved April 6, 2023 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192270/ 
  9. The Importance of the Ratio of Omega-6/Omega-3 essential fatty acids. National Institutes for Health. Retrieved April 6, 2023 from https://pubmed.ncbi.nlm.nih.gov/12442909/

About the author

Mia Barnes is a health writer and researcher who specializes in nutrition, fitness, and mental health.

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