Carnivore Diet: Joe Rogan Swears By It, Doctors Hate It. Who's Right?

The carnivore diet is one of the most polarizing topics in fitness right now.

On one side, you've got Joe Rogan, Jordan Peterson, and thousands of people online claiming it cured their depression, fixed their autoimmune issues, and gave them superhuman energy.

On the other side, you've got doctors and nutritionists saying it's a terrible idea that'll wreck your heart, give you cancer, and leave you nutrient-deficient.

So who's right?

After 13+ years of training clients and watching diet trends come and go, here's my take: Both sides are right—and both are wrong.

What Is the Carnivore Diet?

The carnivore diet is exactly what it sounds like: you eat only animal products. Meat, fish, eggs, and some dairy. That's it.

No fruits. No vegetables. No grains. No legumes. No plant-based foods of any kind.

It's the most extreme version of low-carb eating you can do. Zero carbs. Zero fiber. Just protein and fat.

Proponents say this is how humans ate for thousands of years before agriculture, and that plants are actually inflammatory and harmful.

Why People Swear By It

Let's start with the positive side. Because there are real people seeing real results on this diet.

1. Rapid Weight Loss

When you cut out all carbs, your body enters ketosis. You lose water weight fast, and fat loss follows if you're in a calorie deficit.

High protein and fat intake also keeps you full, so people naturally eat less without counting calories.

2. Reduced Inflammation

Some people report massive reductions in joint pain, skin issues, and autoimmune symptoms when they eliminate plant foods.

Why? Plants contain compounds called lectins, oxalates, and phytates—which can cause inflammation in certain people.

If you're sensitive to these compounds, cutting them out can feel life-changing.

3. Mental Clarity and Energy

A lot of carnivore dieters report stable energy throughout the day—no crashes, no brain fog.

Ketones (produced when eating low-carb) are a very efficient fuel source for the brain. Some people thrive on this.

4. Simplicity

There's no meal planning. No calorie counting. No worrying about macros. Just eat meat until you're full.

For people who hate complexity, this is appealing.

5. Digestive Relief

People with IBS, Crohn's, or other gut issues sometimes find relief on carnivore because they're eliminating all potential irritants.

No fiber, no FODMAPs, no plant compounds—just easily digestible animal protein and fat.

Why Doctors Hate It

Now let's talk about why every mainstream health expert says this diet is insane.

1. No Fiber = Gut Problems

Fiber feeds the healthy bacteria in your gut. Without it, your gut microbiome suffers.

Long-term, this could increase your risk of colon cancer and other digestive issues.

Carnivore dieters will tell you they don't need fiber because they're not eating plants. But the research on gut health says otherwise.

2. Heart Disease Risk

Eating only meat—especially red meat—means you're consuming a lot of saturated fat.

Studies link high saturated fat intake to increased LDL cholesterol, which raises heart disease risk.

Now, some carnivore advocates will say their cholesterol is fine. And for some people, it is. But for others, it skyrockets.

3. Cancer Risk

The World Health Organization classifies processed meat as a Group 1 carcinogen (same category as smoking).

Red meat is classified as Group 2A—probably carcinogenic.

Does that mean eating steak will give you cancer? No. But eating only meat for years? The long-term data isn't great.

4. Nutrient Deficiencies

Plants provide vitamins, minerals, and antioxidants that meat doesn't.

Vitamin C, magnesium, potassium, and phytonutrients are all missing or low on a carnivore diet.

You can survive without them short-term. But long-term? You're asking for problems.

5. Zero Long-Term Studies

There are no long-term controlled studies on the carnivore diet. Zero.

Everything we know is anecdotal—people sharing their experiences online. That's not science.

Maybe it's safe long-term. Maybe it's not. We literally don't know.

The Truth: It Works Short-Term, But Long-Term Is Risky

Here's my honest take after watching people try this diet:

Short-term (1-6 months): The carnivore diet can be incredibly effective for certain people.

If you have autoimmune issues, severe gut problems, or food sensitivities, eliminating all plant foods might give you relief.

It's also a great way to reset your relationship with food if you've been binge-eating processed carbs.

Long-term (6+ months): This is where it gets sketchy.

Without fiber, antioxidants, and a diverse microbiome, you're setting yourself up for potential issues down the road.

Your gut health will decline. Your heart disease risk might increase. And you'll be nutrient-deficient in ways that don't show up immediately but compound over time.

Who Should (Maybe) Try It

The carnivore diet might work for you if:

• You have severe autoimmune issues and nothing else has worked
• You have chronic gut problems (IBS, Crohn's, etc.) and need an elimination protocol
• You want to do a short-term reset (30-90 days max)
• You're experimenting under medical supervision

Even then, I'd recommend transitioning to a more balanced diet after a few months.

Who Shouldn't Try It

Don't go carnivore if:

• You have high cholesterol or heart disease risk
• You have kidney issues (high protein can strain kidneys)
• You're looking for a sustainable long-term diet
• You're trying to build muscle (you need carbs for performance)
• You just want to lose weight (there are better, healthier ways)

What I Recommend Instead

If you're drawn to carnivore because of its simplicity and effectiveness, try this instead:

The 80/20 Animal-Based Diet

Eat mostly animal products (meat, fish, eggs, dairy) but include some plants:

• Low-toxin fruits: berries, apples, bananas
• Easy-to-digest veggies: cooked spinach, zucchini, carrots
• Healthy fats: avocado, olive oil
• Optional: white rice or sweet potatoes for carbs

This gives you the benefits of high protein and fat while avoiding the long-term risks of zero plants.

You'll still lose weight. You'll still reduce inflammation. But you won't wreck your gut or heart in the process.

The Bottom Line

The carnivore diet works—for some people, in the short term.

If you have serious health issues and nothing else has worked, it might be worth trying under medical supervision.

But as a long-term lifestyle? It's a gamble. You're betting that the anecdotal success stories outweigh the lack of long-term research and the known risks of eating only meat.

For most people, a balanced diet with high protein, healthy fats, and some plants is a safer, more sustainable approach.

CJ Critney is a personal trainer and owner of FYTS Fitness in Westlake Village, California, with 13+ years of experience transforming clients through science-backed training and faith-driven discipline.