Is the Carnivore Diet Complete? What We May Be Missing About Fiber, Sleep, and Longevity

By Dustin Strong, CHN, ACN

I love when emerging research challenges us to pause and rethink what we think we know.

Before we begin, let me set the stage clearly—this is a preprint study, meaning it has not yet been peer-reviewed. So this is not clinical truth… yet.

But it is compelling. And perhaps more importantly, it aligns with patterns many of us are already observing in practice.

This study, analyzing nearly 5,000 real-world nights of sleep and dietary data, suggests something powerful:

What you eat today may influence how you sleep tonight—faster than we previously appreciated.

The Fiber Connection No One Is Talking About Enough

What stood out most to me was not just that diet matters—but which part of diet matters most.

Higher fiber intake was consistently associated with:

• Increased deep sleep (your physical repair state)

• Increased REM sleep (your cognitive and emotional processing state)

• Lower nighttime heart rate (a marker of improved autonomic recovery)

In other words, more restorative, efficient sleep.

As clinicians, we are constantly asked:

“How do I increase deep sleep?”“How do I improve REM?”

This study points us toward a foundational—and often overlooked—answer:

We may need to start with fiber.

A Necessary Conversation: Carnivore vs. Completeness

I’ve had many conversations recently with practitioners and patients alike who are exploring—or fully committed to—carnivore-style diets.

And to be clear, I see value in these approaches when used intentionally and seasonally. They can be powerful therapeutic tools in the right context.

But my question has remained consistent:

What about fiber?

This study reinforces something I believe we need to keep in view:

- Removing foods may solve a problem.

- But what we fail to include may create another.

If fiber is playing a role in sleep architecture, nervous system regulation, and gut-brain signaling, then we have to ask:

Is a zero-fiber approach complete as a long-term strategy?

Or is it better understood as a phase within a broader, more adaptive model of care?

More Sleep ≠ Better Sleep

This part of the study validated something I’ve heard repeatedly from patients:

“I sleep longer when I eat heavier meals at night.”

And yes—the data supports that.

Heavier evening meals were associated with slightly longer total sleep time.

But here’s the critical nuance:

They were also associated with higher nighttime heart rate.

In other words, the body is working harder while you sleep.

And this is where we need to shift our thinking:

We are not just aiming for more sleep.We are aiming for more efficient sleep.

Because healing, repair, and neurological restoration require a system that is able to downshift—not stay activated.

Why This Study Matters (and Where It Falls Short)

There are several reasons this research is worth paying attention to:

• It includes a large dataset (~4,800 nights)

• It uses objective sleep tracking, not just self-report

• It reflects real-world conditions, not artificial lab settings

• It applies advanced causal modeling, which strengthens interpretation

At the same time, we should remain grounded:

• It is still observational, not a randomized trial

• Dietary data is self-reported

• It reflects short-term effects, not long-term adaptation

• And again—it is a preprint, not yet peer-reviewed

This is not definitive—but it is directionally meaningful.

A Real-World Approach to Fiber

For those wondering what this looks like in practice, I’ll share what I personally aim for—both for myself and for many of my clients (outside of specific therapeutic phases like carnivore):

My general target is 30–40 grams of fiber per day.

On a typical clinic day, that might look like:

• A handful of raw, sprouted, organic nuts and seeds(pecans, walnuts, pumpkin seeds, Brazil nuts)

• A mix of organic berries(blueberries, blackberries, strawberries, raspberries)

• When I’m especially on track: chia seeds with pineapple and coconut

• A small serving of beans with lunch or dinner

This isn’t about perfection. It’s about consistency and diversity.

Because fiber is not just fiber—it comes packaged with polyphenols, micronutrients, and compounds that influence the gut-brain axis in ways we are still uncovering.

A More Useful Question

Perhaps the most important takeaway is this:

We need to move away from asking:

“What is the best diet?”

And instead begin asking:

“What does this physiology need right now?”

Because health is not static. And neither should our approach to nutrition be.

The Bottom Line

This study adds to a growing body of evidence suggesting:

• 🌱 Plant-forward, fiber-rich eating supports deeper, more restorative sleep

• ⏰ Meal timing influences sleep duration and nervous system activity

• 🧠 Sleep is not just neurological—it is deeply metabolic

And perhaps most importantly:

Deep sleep isn’t just something we optimize at night.It’s something we build—through the choices we make during the day.

This research was shared with me by my colleague, Dr. Jeff Crippen, as part of our ongoing mastermind collaboration—conversations like these are exactly how we continue to refine and elevate our understanding of what truly supports human health.