Your Protein Shake Might be Spiking Your Cortisol

G'day Legend,

Up early this morning in Austin with the BPN athlete team. One of the biggest questions I get is: should I eat before I train in the morning?

The answer depends on your training and your goals. But what you have after your workout? That's a much more specific answer.

And if you're just drinking a protein shake on an empty stomach, you need to read below. You might be spiking your cortisol every single morning without knowing it.

In this week’s newsletter (4 min read):
💪 Why whey on an empty stomach triggers cortisol 
⏰ The timing that actually works
🌙 Casein vs. whey (when to use each) 

If you've got a mate who always hits a shake first thing in the morning, send them THIS link.

Why Whey on an Empty Stomach = Cortisol Spike

Here's what's happening when you drink a protein shake first thing in the morning on an empty stomach.

Whey protein is fast-digesting. It triggers a rapid amino acid release into your bloodstream, which causes an insulin spike. Normally, insulin responds to glucose from carbohydrates. But when you get an insulin response without that glucose buffer, your body compensates by releasing cortisol.

The problem is timing. Your cortisol is already naturally elevated in the morning. That's the cortisol awakening response that gets you out of bed and firing. When you add whey protein on an empty stomach, you're stacking another spike on top of it.

Chronically elevated cortisol leads to:

• fat storage (especially around your midsection)

• poor recovery

• disrupted sleep

• that wired-but-tired feeling that makes training feel harder than it should.

Your protein shake isn't the problem. The timing is. So this is why my shake after my morning workout always has carbs be it a banana and or berries. My afternoon shake will be also not from a fasted stated

The Timing That Actually Works

Post-workout: This is when whey shines. Your cortisol is already elevated from training, your insulin sensitivity is high, and your muscles are primed for protein synthesis. The insulin spike here is beneficial. It drives nutrients into muscle cells.

Mid-morning (after breakfast): If you've eaten a whole food breakfast first, your cortisol levels have normalized and you have a food buffer in your stomach. A protein shake here works as a convenient protein boost without triggering the stress response.

Never first thing AM on an empty stomach: Unless you're training immediately after waking up, this is the worst time for whey. I have my long black coffee, banana or BPN go bar, and 1 scoop of G1M sport (contains electrolytes and carbs from BPN) and I save my shake for after my session.

I used to train fasted and the first thing I would have after a workout was a shake. I did not realize how flat it was making me feel 

Casein vs. Whey (When to Use Each)

Not all protein powders hit your system the same way.

Whey: Fast absorption, rapid amino acid spike. Use post-workout or after meals when you want quick delivery to muscles.

Casein: Slow release, steady amino acid drip over hours. Use pre-bed for overnight recovery or between meals for sustained satiety.

Blends: Moderate release rate. Good for meal replacements when you need something that lasts longer than whey but faster than casein.

The biggest shift for me was switching to casein at night. Whey before bed can disrupt sleep for some people because of that insulin-cortisol response. Casein provides a steady stream of amino acids without the spike, supporting muscle repair while you sleep.

The Signs Your Shake Is Stressing You Out

Pay attention to how you feel after drinking a protein shake.

Jittery or anxious feeling: Even without caffeine, this can indicate a cortisol response.

Afternoon energy crash: Morning cortisol spike often leads to afternoon cortisol crash.

Sleep disruption: If you're drinking shakes late or even early and noticing worse sleep quality, cortisol timing might be off.

Increased belly fat despite hitting protein goals: Chronically elevated cortisol drives visceral fat storage.

Poor recovery despite adequate protein intake: Cortisol is catabolic. It breaks down muscle tissue. If your shake timing is spiking cortisol regularly, you're working against your recovery.

The Protocol

Here's the framework that works.

Morning trainers: Water and electrolytes pre-workout, then protein shake WITH carbs post-workout, then whole food breakfast within 2 hours.

Evening trainers: Whole food breakfast with protein, optional mid-morning shake if needed, whole food meal post-training.

Twice-a-day trainers: Whey after each session, casein before bed.

Rest days: Prioritize whole food protein sources. If you use a shake, have it mid-morning after breakfast, not first thing.

The rule is simple: don't drink whey on an empty stomach unless you're about to train or just finished training.

Quick Notes

🏃‍♂️ In Austin this week with the BPN athlete team. Always good to get the reps in with people who push you.

🎥 Thanks for all the support on the Alex Honnold newsletter last week! The response was massive. If you haven't watched the full YouTube episode yet, check it out HERE.

#EatGoodFeelGood

— DC