The Dawn Effect: Why Your Morning Blood Sugar Might Be Higher (Even in Ketosis)
The Dawn Effect: A Ketogenic Conundrum
Since returning to Melbourne, I’ve been mostly on point: walking 10,000 steps daily, hitting the gym for strength training, and sticking to my high-fat, low-carb diet. In the evenings, my blood sugar is rock solid—low 4s (mmol/L), with ketones ranging from 3.0 to 3.8. Great, right?
Then morning rolls around.
I wake up, fasted, and test again. My blood sugar’s climbed to around 4.8 and—strangely—my ketones have plummeted to 0.8. What gives?
Admittedly, I’ve been eating later at night (life, guests, family rhythms), and I’ve indulged in a few more post-dinner snacks than usual. We’re talking coconut yoghurt, cream, a few too many raspberries—up to a full punnet. Not the end of the world, but possibly enough to nudge my metabolism overnight.
Still, this morning pattern isn’t new. Even during my Bali protocol—where I was crushing it with HBOT, EBOO, IVs, and daily saunas—my morning numbers never quite matched the evening ones.
Turns out, there’s a name for this little biochemical betrayal: The Dawn Effect.
So, What Is the Dawn Effect?
The Dawn Effect (or Dawn Phenomenon) is a natural rise in blood sugar that happens in the early morning—typically between 2 a.m. and 8 a.m.—even when you haven’t eaten. It’s caused by a circadian surge of hormones like:
Cortisol (your “wake-up and get going” hormone)
Glucagon (stimulates glucose release from the liver)
Epinephrine (adrenaline, basically)
Growth hormone
These hormones signal the liver to release glucose into the bloodstream to prepare your body for the day ahead. In most people, this doesn’t cause a problem. But if you’re tracking blood sugar closely—especially on a ketogenic diet—it can feel frustrating to see morning readings that look “worse” than your evening numbers.
Why Do Ketones Drop in the Morning?
Ketones drop for a few reasons:
Increased Blood Sugar = Increased Insulin
Even small bumps in morning glucose can cause insulin to rise slightly. That insulin suppresses ketogenesis.
Overnight Caloric Load
Late-night eating, especially with carbs (like raspberries), can keep insulin circulating into the early morning.
Higher Energy Demands in the Morning
Your body prioritizes quick energy on waking, and even in ketosis, it may tap glycogen reserves first.
Stress Hormones and Sleep Quality
Poor or fragmented sleep increases cortisol, which can both elevate blood sugar and dampen ketone production.
You’re Probably Still in Ketosis
Let’s not throw the butter out with the berries. One or two mornings with lower ketones does not mean you’re out of ketosis entirely. If you’re still averaging sub-5 blood glucose (mmol/L) and producing ketones above 0.5, you’re metabolically flexible and burning fat.
But if you want to nudge your ketones back up:
Finish your last meal earlier—aim for a 12–14 hour overnight fast.
Limit snacking, especially after dinner.
Reduce fruit—even low-carb ones like berries can disrupt ketosis.
Track your sleep and work on reducing late-night stress (yes, even podcasts can count!).
Final Thoughts: A Dance, Not a Straight Line
Staying in ketosis isn’t a perfect, linear process. It’s more like a dance between your goals, your lifestyle, your hormones, and your biology. The Dawn Effect is one of those oddities that reminds us that the body is dynamic—even in a fasted, fat-adapted state.
Tracking helps. Understanding helps more. And sometimes, so does a little grace.
You’re not broken. You’re human. And your body is doing exactly what it’s wired to do. Now that you know how the Dawn Effect works, you can work with it rather than feeling derailed by it.
