Can a Ketogenic Diet Cause Hypoglycemia or Low Blood Sugar?

Short Answer: It can but usually only in the first few weeks of keto and usually in only the most insulin resistant.

Your Old Diet

Before we get into how hypoglycemia is possible with a ketogenic diet, let’s review what happens with your blood sugar levels when you start a ketogenic diet.  While you were eating your traditional high-carb Standard American Diet, you were training your body to produce a large amount of insulin with every meal.  This insulin was important because the high levels of blood glucose your diet was producing was toxic to your body so your body had to get that sugar out of the blood stream and into cells where it could be used as fuel or stored as glycogen or triglycerides.

Your New Diet

Now let’s look at what happens when you start a ketogenic diet.  Your body continues to produce the same amount of insulin when you eat which should cause your blood sugar levels to drop so instead, your body begins to pull sugar out of all the nooks and crannies in your body where it stored it.  The first reservoir to be tapped is the glycogen stored in your muscles.  This stock of sugar is large enough that you can potentially go several weeks with normal blood sugars on keto but eventually those stores run out and that’s when things can get a crazy.

Now for most people, by the time the stores of sugar are depleted, your body has already begun making a few of the necessary changes to your metabolism to run on fat and the feeling of being “run down” or what is sometimes called the “Keto Flu” only last a few days.  The body makes the transition over to running on stored fat and ketones and you are off to the races but for a few people, especially the really insulin resistant ones, you can start to feel the symptoms of hypoglycemia.

Symptoms of Hypoglycemia

Your body begins to produce adrenalin and cortisol, both are stress hormones that tell the liver to produce more blood glucose in the liver.  This causes feelings of hypoglycemia as the body struggles to maintain proper blood sugar levels while simultaneously trying to make the switch over to begin burning fat for fuel.  Symptoms include:

  • heart palpitations or fibrillation
  • dizziness
  • light-headedness
  • sweating
  • headaches
  • nervousness
  • irritability
  • shaking and tremors
  • flushing
  • craving for sweets
  • intense hunger
  • nausea, vomiting
  • panic attack
  • numbness/coldness in the extremities
  • fatigue and shakiness for hours afterwards

Remedies for Hypoglycemia

If you get like this, it is ok to eat something with some sugar in it to get some relief while the body continues to make the transfer.  Something like a piece of fruit of even glucose tablets.  The important thing to remember here is that this goes away eventually.  Soon your body will be humming along just fine on ketones and this will all be a distant memory.  Remember to drink plenty of water and up your salt intake during this time.

If you have any other questions, leave them in the comments below and I’ll answer them as best I can.  Thanks!

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Can a Ketogenic Diet Cause Hypoglycemia or Low Blood Sugar?