The Internet Says Coffee on an Empty Stomach Is Bad for Your Blood Sugar
I wore a glucose monitor to see what happens after my morning coffee.
Scroll through social media long enough and you’ll see some version of it: Don’t drink coffee first thing. Eat within 30 minutes of waking. Wait at least an hour before caffeine. Otherwise, you’re sabotaging your blood sugar for the rest of the day and your hormones are doomed.
So naturally, I wanted to know if that’s true.
No matter where you consume nutrition info (credible or otherwise!), one of the most repeated pieces of advice in wellness right now is that drinking coffee on an empty stomach will spike your blood sugar and derail your hormones.
As a nutrition consultant, this question comes up constantly. In fact, for the women I work with who drink coffee first thing, many arrive feeling slightly guilty about their morning routine (because they’ve been told their coffee habit is sabotaging their hormones). But I get it. When the same advice shows up everywhere, it starts to feel like a rule you’re breaking. Before we panic about our morning cup, it’s worth looking at why this belief caught on in the first place.
Because curiosity got the better of me, I decided to test the claim myself while wearing a CGM. Scroll for my results.
Why People Believe It
The argument usually goes something like this. When you wake up, your body naturally releases cortisol. Cortisol helps you feel alert and mobilizes energy so you can start your day. Coffee also stimulates cortisol and adrenaline. Because of this, some experts argue that drinking caffeine first thing creates a stress response that spikes blood sugar.
Add to that the growing popularity of continuous glucose monitors. People can now watch their blood sugar fluctuate in real time. If someone sees their glucose rise after coffee, it’s easy to assume coffee caused a harmful spike. This idea spread quickly because it does make sense. Stress hormones raise blood sugar. Coffee stimulates stress hormones. Therefore, coffee must be the culprit.
Under the paywall, I’m sharing the following:
Screenshots of my glucose monitor data from 6am-12pm
What the research says about caffeine and blood sugar
When it may make sense to delay your coffee intake
Data on caffeine and hormone/thyroid conditions like PCOS and endometriosis
The very simple rule I follow with coffee that tends to keep energy and glucose stable throughout the day
