Is an Animal Based Diet Healthy? An RD Weighs In.

The animal-based diet (aka the carnivore diet or Lion Diet) has sparked controversy among health professionals in recent years. Its loyal followers claim that eating mostly meat has significant health benefits like weight loss, getting rid of brain fog, better gut health, and so on.

Hi, I’m Jamie, and I’ve been a Registered Dietitian for over 8 years! I specialize in helping women ditch useless diets and build healthy habits, while still eating what they love.

So, is the animal-based diet healthy or not? Let’s look at what we know about it based on research.

A raw steak with a sprig of fresh rosemary on top which is allowed on an animal based diet.

What is an animal-based diet? 

The animal-based diet, otherwise known as the carnivore diet, is a strict diet regime that only allows you to eat animal products – and even some of those are limited.  It’s based on the idea that plants are full of ‘toxins’ that cause inflammation and supposedly harm us.

If you choose to follow it you won’t find a single green veggie, juicy fruit, or carb on your plate! It goes against everything we’ve ever been told about a plant-based diet.

Here are some of the foods that you’re allowed to eat on this meat-only diet (spoiler: it’s a whole lotta animal protein). 

Animal-based foods you can eat:

  • Red meat: beef, pork, lamb
  • Organ meats: livers, hearts, brains, and intestines
  • Poultry: chicken, duck, turkey, geese, quail, and pheasants
  • Fish: Alaskan salmon, cod, herring, mahi-mahi, mackerel, trout, sardines
  • Sauce or gravy: made from meat and butter, no flour allowed
  • Eggs
  • Lard 
  • Bone marrow
  • Butter
  • Salt and pepper
  • Bone broth
  • Water
A chef slicing large beef ribs apart on a wooden cutting board.

Foods you can (sometimes) eat:

Depending on how strictly you follow the carnivore diet, some foods are allowed in very small amounts since they still contain carbs or come from plants.

  • Some dairy products like milk, yogurt and soft cheese  
  • Coffee and tea (limited since these come from plants)

Foods you can’t eat:

These foods are a hard “no” for strict carnivore dieters. 

  • Fruit: apples, oranges, berries, grapes, avocado, bananas, pomegranates, peaches, nectarines, mangoes, fruit juices, etc.
  • Vegetables: lettuce, spinach, kale, tomatoes, cabbage, broccoli, cauliflower, green beans, carrots, eggplant, etc.
  • Grains: rice, oats, pasta, bread, flour, quinoa, etc.
  • Legumes: peas, soybeans, black beans, navy beans, chickpeas, lentils, pinto beans, etc.
  • Nuts: almonds, pistachios, walnuts, cashews, peanuts, etc.
  • Seeds: pumpkin, hemp, flax, sunflower, chia, etc.
  • Sugar and sweets

Animal Based Diet Claims

Carnivore diet enthusiasts claim that an animal-based diet is the cure to just about everything health-related, but a few of the most commonly reported ones are:

  1. Decreased inflammation
  2. Better insulin resistance
  3. Weight loss
  4. Mental clarity
  5. Gut healing

Sounds impressive, right? However, all of these positive effects are self-reported and based on testimonials of carnivore dieters, meaning there’s no solid research to back it.

There are also a few other self-reported cases of it relieving symptoms of autoimmune disease. But again they’re based on a few people’s own experiences and are not well-studied.

The Research (spoiler: there’s almost none)

When you go hunting for research articles about the animal based diet, you’ll only find this one. In the study, participants were only included if they had been eating the carnivore diet for over 6 months. 

Many said they were able to stop taking diabetes medications, felt more energized, slept better, and had better overall health on this meat diet.

But there’s a catch: all of the findings were self-reported and based on each person’s perception of the effects, not measurable data (2).

The study also did not require participants to validate their reported health changes. So, there’s no way to know whether or not the self-reported data is accurate.

And as mentioned, participants were only included if they had been eating the diet for over 6 months. It didn’t include anyone who was unable to stick to the diet for 6 months or experienced negative effects when they started following it. Two super important pieces of information.

The bottom line: The group of animal based eaters in this study were as hardcore carnivore as they come. While it looks incredibly impressive at a glance, it really should be taken with a grain of salt.

A study full of self-reported findings its nowhere near adequate. The animal based diet desperately needs better research, and more of it before it’s claims can be respected.

Pros and Cons of the carnivore diet

Like any diet, there are pros and cons, but I’ll warn you right off the bat, the list of cons is a lot longer for the carnivore diet. First, let’s look at the potential benefits of the carnivore diet.


1. Less decision-making with meals

Because the diet is so limited, you don’t have to overthink your grocery list. That’s a win…… right? Over 80% of the store is off limits since you’re only allowed to shop in the meat section – and occasionally visit dairy. 

2. Self-reported claims

Some people have reported feeling better on this eating plan. It’s super important to remember that this is self-reported data vs. information gathered in a formal study. However, I don’t want to completely ignore or discredit people’s personal experiences, so it’s worth mentioning.

With that being said though, it makes me wonder what these folks were eating before trying carnivore. Maybe they were eating more highly-processed foods and their body felt better with less.

It’s very possible that the people who are currently feeling good on carnivore might still feel good (possibly even better) with a less restrictive plan than what carnivore recommends. 


Aside from the simple menu, there are major downsides to consider.

1. High in red meat and saturated fat

The Dietary Guidelines for Americans and the American Heart Association recommend limiting your diet to 10% saturated fat or less (3, 4). 

The carnivore diet recommends eating 70-80% animal fat, and most of these foods are high in saturated fat, which can increase your cholesterol levels and increase your risk for heart disease (5).

If you have high cholesterol to begin with or you’re at risk for cardiovascular disease, this diet probably isn’t for you.

Research also shows that diet high in red meat can increase your risk of colon cancer (6). If cancer runs in your family or you’re predisposed in any way, I would advise against considering this diet.

2. Negative side effects

When you start the carnivore diet you can expect to go through some grueling side effects. Some of these are similar to keto diet side effects, but likely more intense since this is a zero carbs diet.

If you head to google, you can see that what’s often self-reported includes:

  • Nausea and diarrhea
  • Dizziness
  • Irritability
  • Bad breath
  • Body odor
  • Brain fog
  • Cramping
  • Heart palpitations
  • Night sweats
  • Exhaustion
  • Poor focus
  • Cramps

The carnivore diet is ultra low carbohydrate (this is essentially a ketogenic diet without plants) and missing tons of health-promoting nutrients, so this is no surprise.

2. Expensive

Your grocery bill is likely going to skyrocket on this diet since animal foods are expensive. There are a lot of blogs that reveal ‘how to eat cheap as a carnivore,’ but most recommend increasing your fat intake since it’s cheap and purchasing the lowest quality meats on the market. 

3. Super restrictive

If you like a variety of foods, the carnivore diet is going to be hard to follow. When you follow it to a T you can say goodbye to juicy fruits, crunchy vegetables, and delicious desserts. The carnivore diet is arguably the most restrictive diet out there.

It takes a lot of willpower to follow such tight rules, and you’re likely to experience lots of cravings.

If you’re someone who has struggled with disordered eating in the past, I highly recommend running far, far away from this one.

4. Missing important nutrients

There’s no denying that an animal-based diet puts you at risk for nutrient deficiencies.

Just to give you one example, most of the food you’re allowed to eat on the carnivore diet lacks Vitamin C which prevents scurvy. The easiest way to get enough is to eat fruits and veggies (7, 8). 

The meat-based diet is also missing fiber, which promotes a healthy gut, lowers cholesterol, keeps your blood sugar balanced, and even decreases your risk for certain diseases (10). You’re also way more likely to be constipated without fiber.

Cutting all fruits, veggies, legumes and whole grains out of your diet also eliminates many micronutrients and disease-fighting antioxidants from your diet.

Diets that are high in plant-based foods are well-researched and have been associated with lower risk of heart disease, some cancers, Alzheimer’s, and type 2 diabetes (11).

Not only does the carnivore diet cut these healthful food groups out, but there’s no research that proves following an animal-based diet is better.

5. The science doesn’t back it up

The only research study available is a self-reported study and reported health changes were not checked for accuracy. Simply put: the science just isn’t there to back up the claims.

On the contrary, diets that have a variety of foods and promote balanced eating with lots of plant-based foods, like vegetarian diets or the Mediterranean diet for example, are very well researched and have been associated with lower risk of chronic disease (12). They’re also more sustainable diets.

A spread of Mediterranean diet approved foods like olive oil, fruits and vegetables, fish and legumes.

Should you try it?

Most claims for this diet are anecdotal and self-reported, and there’s certainly no long-term research on an animal-based diet.

The carnivore diet at this point is un-researched and goes against evidence that proves fiber-filled carbs, fruits, and vegetables are good for us. Researchers have consistently found eating non-starchy veggies, plant proteins, fruits, nuts, and legumes actually decreases our risk of chronic diseases (13).

Based on the evidence, it’s better to focus on a well-rounded, balanced diet with a focus on moderation and including more plant foods.

If you’re considering becoming a carnivore, you also have to think about the sustainability of the diet. Are you committed to cutting out all fruits, vegetables, and carbs? If the answer is no it’s best to stay away. 

The bottom line is that its ultra restrictive with no proven health outcomes to justify putting yourself through that.

Do I recommend it as a Registered Dietitian?

As a dietitian, an animal-based diet isn’t something I’d recommend, ever. In fact, based on what we know about human nutrition, trying the carnivore diet is more risky to your health than beneficial.

Not to mention, it’s difficult to sustain because it’s so restrictive. And again, it goes against so much research we have about the benefits of eating more plants. 

It’s totally unrealistic for most people to follow and leaves the potential for huge nutritional gaps. In short, it’s simply unnecessary to live a healthy life and puts you at risk for health issues.

Instead, I support a balanced nutrition approach for good health, aka ditching restrictive diets. I encourage you to fill your plate with lean protein, fiber-filled carbs, and your favorite fruits and vegetables – foods you actually like that fuel you properly!

Have you tried the carnivore diet before? Or are you currently on it? Comment below to share your experience!

Other articles you might like:

30-Day Keto Challenge: Should You Try It?

5 Ways to Reset Your Metabolism

Why Do I Keep Eating After I’m Full (And What To Do About It)

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It's me, Jamie!

I’m a Registered Dietitian dedicated to helping you break free of the all-or-nothing dieting with balanced and realistic healthy eating.

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Meet Jamie

I’m a Registered Dietitian and I’ve been exactly where you are, right now. The all or nothing dieting, the constant food guilt, the scale obsession, absolutely no balance with food…. Sound familiar?