Dawn Phenomenon

We are often asked, “Why is it that my fasting blood glucose is always so much higher than at any other time of the day? Especially when I have had nothing to eat since supper (or bedtime)!”

Dr. Jason Fung, author of The Diabetes Code, explains it thoroughly in this article from which I have gleaned information and tried to summarize and provide excerpts from the full article.


The circadian rhythm creates the Dawn Phenomenon. “Just before awakening (around 4 a.m.), the body secretes higher levels of growth hormone: cortisol, glucagon, and adrenaline. Together, these are called the counter-regulatory hormones. That is, they counter the blood-sugar-lowering effects of insulin, meaning that they raise blood sugars. The nocturnal surge of growth hormone is considered the primary cause of the Dawn Phenomenon.

“These normal circadian hormonal increases prepare our bodies for the day ahead. That is, glucagon tells the liver to start pushing out some glucose. Adrenaline gives our bodies some energy. Growth hormone is involved in repair and new synthesis of protein. Cortisol, the stress hormone, increases as a general activator. After all, we are never quite so relaxed as deep sleep. So these hormones gently get us ready to wake up. A good ol’ fashioned hormonal kick in the ass, so to speak. Hormones are secreted in a pulsatile manner peaking in the early morning hours then falling to low levels during the day.

“Since these hormones all tend to raise blood sugars, we might expect that our sugars would go through the roof in the early morning. This does not actually happen [in non-diabetic people]. Why? Insulin secretion also increases in the early morning to counteract the counter regulatory hormones. In other words, insulin is there to make sure blood sugars do not go too high. However, if you look closely at the blood sugar readings, there is a slight increase in the morning time.

“So, in the normal, non-diabetic situation, blood sugars are not stable throughout 24 hours. The Dawn Effect happens in normal people. This is easily missed because the magnitude of the rise is very small – from 89 to 92 mg/dL. However, this effect was found in every patient studied. So, unless you are specifically looking for the Dawn Phenomenon, you are likely to miss it.

“Think about it this way. Your body has the ability to store food energy as sugar (glycogen) and fat. When you eat, you store food energy. As you sleep (fasting), your body needs to release this stored energy. Around 4 a.m. or so, knowing that you will soon be waking up, your body prepares you for the upcoming day. It does this by increasing counter-regulatory hormones to release sugar into the blood. You can see that glucose production falls overnight and starts to ramp up around 4 a.m. In order to prevent the sugars from rising too much, insulin increases to act as a ‘brake’ on the system….”


“However, in Type 2 diabetes, the body has high insulin resistance, meaning that the insulin has minimal effect at lowering the blood sugars. Since the counter regulatory hormones (mostly growth hormone) still are working, blood sugars rise unopposed, and are therefore much higher than the normal non-diabetic situation….

“In the Dawn Phenomenon, the body is under orders to release some of the stored sugar into the bloodstream. Like an over-inflated balloon, the liver puts forth prodigious amounts of sugar in order to relieve itself of this toxic sugar burden.

“Some people have normal blood sugars except for the Dawn Phenomenon. This still indicates that there is too much sugar stuffed into their liver. They need to keep burning down that sugar. It means there is much more work to be done before they are cleared of their diabetes.

“Think about it this way. The Dawn Phenomenon is simply moving sugar from body stores (liver) into the blood. That’s it. If your body stores are filled to bursting, then you will expel as much of that sugar as possible. By itself, Dawn Phenomenon is neither good nor bad. It is simply a marker that your body has too much sugar. Solution? Simple. Either don’t put any sugar in (Low Carb High Fat) or burn it off (Intermittent Fasting). Even better? LCHF + IF.”

Those of us who have experienced Dawn Phenomenon (Dr. Fung says 75% of us do), know that the fasting blood glucose number that evidences Dawn Phenomenon is the last one to go down!


Some people erroneously believe they need to have a bedtime snack in order to prevent Dawn Phenomenon. Nothing could be further from the truth! We at Adventist Vegetarian Diabetics do not recommend snacks during the day and especially not at bedtime. However, until you can re-train your brain and body that you do not need a bedtime snack, and you still “feel hungry,” have a small protein/fat snack, like full-fat cheese or natural almond butter. But nothing that is primarily carbohydrates!

If your fasting blood glucose is considerably higher than other numbers throughout the day, you can eat breakfast normally and just ignore the Dawn Phenomenon number. Check your blood glucose before and after meals, just to keep track of your numbers. Or you can delay your first meal of the day for a few hours to allow your blood glucose to go down more. Be sure to drink enough water to stay hydrated until you are ready to eat.

Make sure you are getting adequate sleep at night. Daily exercise is a must! Eliminate all forms of sugar but especially fructose, and all or most processed food products. Eat real food.

If you are taking prescription medications, you need to consult with your doctor. Never stop, start, or change dosages of medications without instructions from your doctor or other qualified health care practitioner.

Dr. Fung says that one of the worst things you can do is to pump injected insulin into your body. Even though the extra insulin will make your blood glucose numbers go done, this does nothing to address the real problem of too much sugar still in your body. When your blood glucose number goes down, it’s because the sugar that was in your blood has gone into your liver for storage, where it ultimately can cause non-alcoholic fatty liver disease (NAFLD).

He says, “Insulin moves the sugar from the blood where they [your doctors] see it, and into the tissues (liver) where they cannot. It is no less bad, but they are able to pat themselves on the back for a job ‘well done.’ It is not different from moving garbage from the kitchen to underneath your bed. It smells the same, but you can’t see it.”

So, yeah, talk to your doctor about insulin, too.

You can read the complete article by Dr. Jason Fung at https://idmprogram.com/dawn-phenomenon-t2d-8/.

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