By Dr Joe

What do you get on this page regarding blood sugar spikes and crashes?

Well, in a nutshell, you are going to get the know-how on what a blood sugar spike is, what a blood sugar crash is, why your blood sugar actually spikes and crashes, the event, what triggers a blood sugar crash, the symptoms of blood sugar crash and how to prevent a blood sugar crash.

Keep reading…

blood sugar roller-coaster


Blood sugar spikes and crashes. Don’t you just hate it when that happens to you. It’s like your body doesn’t know what it wants to do.

Blood sugar high one minute, then low the next. Why can’t my blood sugar stay in the normal zone?

It’s easy to point the finger at our bodies but we should ideally be pointing the finger at the kinds of foods we eat, if blood sugar spikes and crashes are a frequent occurrence.

A blood sugar high followed by a blood sugar low is invariably the result of dietary choices. Yes, there are a few other causes besides diet but for the most part, diet is to blame for blood sugar spikes and crashes.

What is a blood sugar spike?

In simple terms, a blood sugar spike is one that overshoots beyond the expected target blood sugar for the index event.

Right, I can hear you shouting…WHAT?
…at your computer screen or smart phone. Dr Joe, explain some more.

Okay, let me explain.

The American College of Clinical Endocrinologists has a recommended target blood sugar level for when we are fasting, blood sugar level at 1 hour after we eat and target blood sugar 2 hours after a meal.

The recommended blood sugar target levels are shown in the image below. So, if your blood sugar overshoots above that recommended target, then that is a blood sugar spike.

non diabetic blood sugar chart


You should see the target as a ceiling rather than something to aim for.

So, for instance, if 1 hour after your meal, your blood sugar is 180mg/dl (10mmol/l), that is well over the recommended 1-hour post-meal level of 140 mg/dl (7.8mmol/l). That will constitute a blood sugar spike. Does the definition of a blood sugar spike make sense to you now? I hope so.

Now, what is a blood sugar crash?

A blood sugar crash is when your blood sugar level takes a nose-dive below 72mg/dl (4.0mmol/l). People respond differently to low blood sugar levels differently.

I, for instance can still function reasonably well with blood sugar level of 63mg/dl (3.5mmol/l).

You, on the other hand may be hitting rock bottom at such a level with nasty symptoms of blood sugar crash.

The point being; everyone is different. If you are having sugar crash symptoms and your sugar is below 72mg/dl (4.0mmol/l), then it makes sense to act. It’s a crash!

What happens in blood sugar spikes and crashes?

It’s a very simple chronology of events.

You have your meal.

The food is broken down to smaller units by the process of digestion. Usually this refers to a carbohydrate meal which is broken down to glucose.

The glucose is absorbed from the intestines into the blood stream.

Once your blood sugar rises above 100mg/dl (5.5mmol/l), the beta cells in your pancreas receive an alarm call to lower blood sugar back down to normal.

The beta cells respond by releasing the stored insulin hormone inside them into the blood stream to lower blood sugar. Yes, your pancreatic beta cells store insulin inside them ready for action when needed.

Insulin is like a firefighter waiting at the fire station waiting for a call to put out fire in a building. The fire station being the pancreas. Insulin is just there waiting to be released when the call comes along.

And “the call” comes along once blood sugar rises above 100mg/dl (5.5mmol/l).

Once that happens, insulin is released into the blood stream.

The release of insulin happens in pulses. The 1st release should do the job of lowering blood sugar back to below 100mg/dl (5.5mmol/l).

If the first phase of insulin does not lower blood sugar to the desired level, then a 2nd release takes place 20 minutes later.

The 2nd phase insulin response to the high blood sugar is expected to bring blood sugar back down to normal levels.

In a person whose metabolic pathway is intact, this sequence of blood sugar rise and lowering of the blood sugar happens smoothly without any drama.

So, what then triggers the blood sugar spike and the crash?

Glad you asked.

In an individual that experiences blood sugar spikes and crashes, the action of the beta cells in the second phase insulin release is the issue.

It would appear that the pancreas gets “too excited” at the prospect of being asked to release some more insulin in the 2nd phase response.

What then happens is that; the beta cells of the pancreas respond too dramatically in phase 2 release, pushing out more insulin than is required for the remaining blood sugar lowering task.

The net result is a dramatic fall in blood sugar resulting in the blood sugar crash.

And the symptoms of blood sugar crash are not very pleasant.

Symptoms of blood sugar crash includes headaches, dizziness, trembling, sweating, nervousness, feeling agitated, becoming weak and fatigued. Follow that link for a complete look at the symptoms.

low blood sugar symptoms


The initial blood sugar crash symptoms you feel are due to the release of adrenaline. The adrenaline is released by your body in response to the stress of the blood sugar crash.

Here’s something else that happens:

One of the symptoms of blood sugar crash is hunger. Do remember, I said earlier on that your pancreas releases a disproportionate amount of insulin to lower the blood sugar spike.

This disproportionate amount of insulin released into the circulation is what causes the blood sugar crash following the blood sugar spike.

The insulin produces a sudden “whoosh effect” clearing the sugar from the blood circulation by forcing the sugar into the cells in a dramatic way.

That’s not the end of the story though. The disproportionate high amount of insulin circulating in the blood does something else.

It makes you hungry!

Yes, Insulin makes you hungry.

Which means you want to eat again. In a way, it’s actually a protective effect. Insulin makes you hungry so you eat to replenish your low blood sugar. This is because low blood sugar is dangerous and your body doesn’t like it one bit.

Depletion is a trigger for Repletion. Kinda makes sense, right?

So, you eat again and if you keep eating the wrong foods that trigger the blood sugar spike and crashes, the process will repeat itself again.

You end up with a blood sugar spike and crash roller-coaster ride.

So, what foods are the wrong foods that trigger blood sugar spike and crash?

You guessed it. Refined carbs and Sugary foods, I’m afraid.
Refined carbs are easily digestible. This means they get digested very easily releasing their glucose units quickly.

Quick digestion, quick glucose absorption equates to quick rise in blood sugar and of course a blood sugar spike.

Then the cascade of events I described above ensues. See image below.

carbs and hunger

Carbs belong to 3 main groups:

  • Sugar
  • Refined carbs
  • Wholegrain carbs

Sugar refers to table sugar, fizzy drinks and sodas, candies, milk chocolate, your favourite Starbucks coffee and even Costa. In short, any sweets fall into this category.

Refined carbs refer to carbohydrate foods that have been stripped of their bran and germ leaving the endosperm only. Exposed endosperm is a recipe for quick digestion, quick absorption and blood sugar spikes.

Refined carbs lack the fiber that slows down the digestive process. Examples of refined carbs are white rice, white flour, white bread, bagels, muffins, cakes, doughnuts and other baked goods.

Wholegrain carbs have their bran and germ intact. The bran and germ constitute the fiber. The fiber applies brakes to the digestive process making the release of glucose from the food a slower process.

The means a gentler release of the glucose into circulation. This prevents the dreaded blood sugar spike and crash that follows. Foods like Amaranth, quinoa, bulgur wheat, oatmeal, brown rice are examples of wholegrain carbs or complex carbs.

Something to bear in mind:
If you are experiencing, blood sugar spikes and crashes, especially frequently, you may want to look into it further.

This is because, blood sugar spikes and crashes may be caused by the following apart from sugar and refined carbs:

  • Reactive hypoglycemia
  • Pre-diabetes
  • Obesity
  • Stomach surgery that causes food to hasten through to the small intestines

Reactive hypoglycemia, prediabetes can be diagnosed by your medical practitioner. And of course, if you’ve had stomach surgery, then the cause will be obvious to you by now.

So, how do you avoid blood sugar spikes and crashes?

It’s very simple. See image below for guidance.


blood sugar spikes and crashes prevention


If you are one of those experiencing the blood sugar roller coaster problem frequently, see your doctor to exclude reactive hypoglycemia and pre-diabetes.

Beyond that, the mainstay of avoiding blood sugar spikes and crashes is to avoiding refined sugar, refined carbs and sweets.

The way to go is to eat complex carbs only. The management of blood sugar spikes and crashes is similar to the management of non-diabetic hypoglycemia. Follow that link as I have more detailed management tips there.

But you can’t go wrong by eating complex wholegrain carbohydrates.

Along with eating complex carbs, include the pulses in your diet. Eat peas, beans, lentils, vegetables and you will experience a steady release of glucose that will keep your blood sugar in the normal zone – the green zone. No spikes. No crashes.

Suggested further reading:
1 Unique Spice That BEATS Abdominal Fat (plus controls blood sugar)