“I'm a diabetic, FYI.”

The 5 blood sugar patterns to master as a type 2 diabetic

Saturday, June 15, 2019

Jason Tu
By Jason Tu

Living with type 2 diabetes can feel like a game of Flappy Bird at times. Too high, and you hit a pipe. Too low, and you hit a pipe… or fall onto the floor.

Photo by @borisworkshop on Unsplash.
Photo by @borisworkshop on Unsplash.

Lucky for us diabetics, if you’ve pricked your fingers enough times (or if you have a CGM), you’ll start to notice a couple of recurring patterns – 5 to be exact! (At least in my experience as a type 2 diabetic.)

I list the patterns below, and discuss solutions for each:


  1. The carb effect
  2. The protein effect
  3. Exercise
  4. Dawn Phenomenon
  5. Sleep

The carb effect

A post-lunch blood sugar spike.
A post-lunch blood sugar spike.

The first pattern you should recognize: when you consume foods containing carbs, you raise your blood sugar! (On the other hand, consuming pure dietary fat doesn’t affect your blood sugar at all – try eating a tablespoon of butter to see.)

This is normal, and everyone experiences a rise in blood sugar after a meal. However, if your blood sugar is spiking too much (above 120 mg/dL or 6.7 mmol/L is my threshold), try some of the following:

  • Let your blood sugar drop further before eating.
  • Lower (or eliminate) the sugar and refined carbs in your meal.
  • Replace the sugar and refined carbs with fibrous, cruciferous vegetables (to feel full).

Generally, I find that if if you feel heavy or sleepy after a meal, it means you ate too much!

The protein effect

Gradual rise in blood sugar after a steakhouse dinner, followed by some exercise.
Gradual rise in blood sugar after a steakhouse dinner, followed by some exercise.

If you’ve ever had a high protein meal – say a large steak, or large cut of fish – and noticed that your blood sugar rises very steadily over the course of 5 hours, then this pattern applies to you.

What gives, right? I thought protein didn’t get turned into sugar. The science roughly goes like this:

  • Protein stimulates glucagon and insulin in equal amounts.
  • Glucagon tells your liver to release its stored glycogen, and convert the glycogen to blood sugar.
  • Insulin stores blood sugar in the form of glycogen.

In a non-diabetic, insulin-sensitive person, the opposing action of glucagon and insulin keep their blood sugar levels steady.

However, in a type 2 diabetic, insulin-resistant person, the glucagon works as usual, but the insulin is deficient. So the glucagon wins out over time, which is why you see a gradual rise in your blood sugar level.

Marty Kendall of the Optimizing Nutrition blog explains this protein effect in more nuance.

Suffice to say, if you experience this protein effect, you could:

  • Moderate the amount of protein you eat.
  • Build more lean muscle mass through exercise.

Which leads us to the next pattern…


I’ve found that low-intensity, long-duration exercise (like walking, running, biking, and swimming) almost always lowers your blood sugar. This makes it useful as immediate treatment for high blood sugars. Just go for a long walk:

What happens to your blood sugar during a steady jog.
What happens to your blood sugar during a steady jog.

On the other hand, high-intensity, short-duration exercise (like weightlifting, sprinting, and rock climbing) will spike your blood sugar temporarily, but keep your blood sugar lower overall for a period of time afterward:

A blood sugar graph of my first time at a bouldering gym.
A blood sugar graph of my first time at a bouldering gym.

Ultimately, I think both types of exercise are highly beneficial for us diabetics. Anything helps!

Dawn Phenomenon

Ever find your blood sugar to be out-of-range upon waking up, even when you haven’t eaten anything the night before?

I used to experience this every morning, and apparently people call it Dawn Phenomenon:

Dawn Phenomenon, between 4am and 8am.
Dawn Phenomenon, between 4am and 8am.

Dawn Phenomenon itself is well-understood: our liver dumps sugar (that is, it converts our stored glycogen into blood sugar) to ready us for the day ahead. However, because type 2 diabetics are insulin-deficient, we experience an unfortunate rise in blood sugar levels.

To counter Dawn Phenomenon, most advice recommends eating a snack at various times:

  • Eat a snack containing carbs before bedtime.
  • Eat a snack containing protein before bedtime.
  • Eat immediately after waking up, so you trigger insulin, which will bring your blood sugar down.

But all of that advice strikes me as wrong, because they never worked for me. I think the root of the problem is that we’re still eating too many carbs. Since we’re eating too many carbs, our livers still have glycogen in the tank – ready to be converted to blood sugar upon waking.

Dr. Jason Fung explains the mechanics in detail in his blog post about Dawn Phenomenon.

I eventually cured my Dawn Phenomenon by eliminating all carbs from my diet, with the exception of vegetable carbs. I still see some Dawn Phenomenon, but the effect is far less severe:

Dawn Phenomenon, between 4am and 8am. Blood sugar gradually comes down after waking.
Dawn Phenomenon, between 4am and 8am. Blood sugar gradually comes down after waking.

Some other techniques involve fasting (for at least 12 hours) to deplete your glycogen stores, as recommended by this Reddit post.

Sleep and stress

Last but not last, I find that sleep is essential for keeping your blood sugar stable throughout the day.

I find that when I run on very little sleep (say, less than 5 hours), it becomes very difficult to keep my blood sugar level throughout the day:

A Friday with very little sleep.
A Friday with very little sleep.

Whereas I fare much better on weekends, when I’m allowed to sleep in:

A day's graph, backed by a long night of sleep.
A day's graph, backed by a long night of sleep.


To summarize, here’s a table of all 5 patterns, and the solutions for addressing each one:

Pattern Solution
The carb effect: too many carbs Eat fewer carbs, and eliminate sugar and refined carbs
The protein effect: too much protein Eat slightly less protein, and do more exercise
Exercise: helps lower blood sugar Be aware that exercise may temporarily increase blood sugar
Dawn Phenomenon: raises your blood sugar in the morning Cut down on carbs (or do fasting) to empty your glycogen stores
Sleep and stress: lack of sleep keeps your blood sugar elevated Get more sleep

With knowledge of the 5 patterns above, you can easily debug the multiple root causes of any instance of elevated blood sugars.

For example, if you notice that consuming carbs for breakfast (the “carb effect” pattern) after a night of little sleep (the “sleep and stress” pattern) spikes your blood sugar particularly badly, you can make a note to skip breakfast whenever you’re running low on sleep. This is because you are more insulin-sensitive later in the day.

Alternatively, you could just get more sleep. 🙂

What has your experience been with the different blood sugar patterns? Please leave a comment below!