Carnivore Diet Pros and Cons: Why High-Animal-Protein Diets Accelerate Aging

This article seeks to address the ongoing debate between animal-based diets and plant-based diets. Both sides present strong opinions — carnivore diet proponents often criticize plant-based diets, while plant-based advocates frequently oppose meat-heavy diets. Each approach offers certain benefits but also comes with drawbacks.

Despite substantial scientific evidence questioning the long-term health of high-animal-protein or meat-based diets, many people still consider them healthy. On the other hand, plant-based diets have their own challenges, which we will examine.

Ultimately, we suggest a balanced diet that includes both plant-based foods and moderate amounts of animal protein. Combined with smart supplementation and a healthy lifestyle, this approach may offer the best outcomes for longevity and overall health.

Why Explore Carnivore Diet Pros and Cons?

We tackle this topic from a unique angle: aging. By gaining a deeper understanding of why we age, you can more accurately evaluate the long-term impact of different diets and foods.

In our view, high-animal-protein diets are detrimental in the long run, as a high intake of meat accelerates key aging processes, regardless of whether the meat is grass-fed or antibiotic-free.

On the other hand, plant-based diets can also contribute to aging, partly due to the high risk of nutrient deficiencies, even with the use of supplements.

What Defines a High-Animal-Protein Diet?

First, let’s define what high-animal protein diets are, because we don’t want to run into the issue of consuming too little protein. Consuming too little protein can be deleterious to our health as well, including higher risks for osteoperosis, sarcopenia and premature death. So, we need an adequate amount to maintain our health, but not too much.

To that point, consuming 0.60 grams or protein per pound of bodyweight per day, to 0.72 grams for those weightlifting or over 50-60 years of age is adequate for general health, and maintenance and growth of muscle. So, for a 150 pound person, consuming roughly 90 to 110 grams of protein per day is a good range to shoot for.

Going significantly above these levels, especially with animal proteins like red meat, would be considered a high animal protein diet and is what we will address in this article. Conversely, going significantly below these figures for an extended period of time would also be of concern for distinct reasons.

Why Meat Eaters Often Believe a Carnivore Diet Is “Healthy”

Many advocates of high-animal-protein diets, such as the paleo, caveman, carnivore, Atkins, or Dukan diets, are often deeply convinced that their eating approach is superior. They consider it the healthiest of all diets.

Here are a few reasons why proponents of high-animal-protein diets often consider their eating habits to be healthy.

Short-Term Benefits

People following a high-animal-protein diet often feel great in the short term. They may experience increased strength, energy, muscle growth, weight loss, and improved insulin resistance.

However, these benefits are temporary. When examining the long-term effects over decades, it becomes evident that such diets can accelerate aging and raise the risk of age-related diseases, including heart disease and cancer. More on that below.

The Illusion of Health Improvements

Sometimes, people on a high-animal-protein diet not only feel better but may also see improvements in certain conditions, such as autoimmune diseases like multiple sclerosis (MS) or rheumatoid arthritis. However, these benefits are not primarily due to the meat itself, as meat can actually promote inflammation (more on this below).

Instead, the improvement often comes from other factors, such as a significant reduction in pro-inflammatory sugars and refined carbs, like bread, potatoes, pasta, and rice. These diets typically minimize these types of foods (which we also recommend reducing).

Additionally, high-animal-protein dieters tend to:

• Avoid junk food
• Consume more vegetables
• Incorporate healthy, anti-inflammatory fats
• Eliminate potential triggers of autoimmune diseases, such as gluten, soy, and dairy

In this way, a carnivore diet acts as a type of restriction diet. However, meat and certain fats found in meat can also cause inflammation (R,R). So, a diet that limits meat intake and focuses on low-glycemic vegetables, legumes, mushrooms, and healthy fats would be even more beneficial (see below for more details).

The Prehistoric Take

Carnivore dieters often believe that because prehistoric humans consumed large amounts of meat, a meat-heavy diet is optimal for modern humans. However, this reasoning has two major flaws:

1. Scientists are unsure if prehistoric people truly consumed large amounts of meat, as meat was often difficult to obtain.
2. Even if early humans did eat a lot of meat, that doesn’t necessarily mean it’s beneficial for longevity.

Nature’s primary concern is reproduction, not long life; it prioritizes survival through the reproductive years (teens and twenties). What happens afterward is of no consequence to nature. This is why aging exists: to make room for future generations.

Even if prehistoric diets high in meat raised the risk of heart disease by age 60, it wouldn’t have been an issue. Most people in prehistory didn’t live that long. They typically died from external factors such as accidents, disease, violence, or starvation.

As modern humans, our goals are different. We seek a long, healthy life, which somewhat conflicts with nature’s agenda. While eating a lot of meat may have supported reproductive success in early humans, if it also accelerated aging, that would align with nature’s priorities but not with our own.

Plant-Based Diet Vs. Animal-Based Diet

So, should we follow a plant-based diet or a meat-based diet? 

If we look at the whole of scientific studies, numerous studies show that people who follow a plant-based diet live longer and are healthier (R,R,R,R,R,R,R,R). 

This is despite the increased risk of vitamin and mineral deficiencies on a plant-based diet.

However, we believe there’s room for further improvement.

The key is to base your diet on low-starch plants, complemented by moderate amounts of animal protein—primarily fish and, if desired, some poultry. Red meat should be consumed sparingly, and preferably as organ meats. Additionally, incorporating plant-based protein powders, like hemp, along with nutritional supplements, can help fill in the inevitable nutritional gaps that occur with any diet—whether it’s carnivore, vegan, Mediterranean, or otherwise.

In short, no diet is perfect. That’s why supplements and targeted protein powders are essential, as nature doesn’t offer flawless solutions.

47 Scientific Arguments on Why a Carnivore Diet Accelerates Aging 

So why are high-animal protein-diets unhealthy in the long term? We listed the main arguments for you below. 

Longevity Zones and Protein Intake

1. There is no longevity zone in the world where people live longer by eating lots of meat or animal protein. Longevity zones, also called “Blue Zones,” are areas where people live considerably longer. What all Blue Zones have in common is that people consume few animal products . For example, long-lived people in Okinawa (Japan), Sardinia (Italy), Icaria (Greece), or the Seventh-Day Adventists in California consume little or no meat (R). Of course, there are many other reasons why people live longer in these zones, but a low animal protein intake is a clear common denominator.  

2. Mostly, people who reach a very old age (e.g., centenarians) do not consume a lot of animal protein. They reach a high age without eating lots of meat or without following a paleo diet or drinking whey shakes (R,R,R,R). 

Overall Scientific Evidence 

3. Most studies clearly show that consuming a more plant-based diet is much healthier than a diet high in animal protein (R,R,R,R,R,R,R). There are some studies claiming that high meat intake is not unhealthy, but they are significantly in the minority; the scientific evidence is overwhelmingly in favor of a more plant-based diet instead of a high-animal-protein diet. 

Protein Accumulation Is One of the Hallmarks of Aging

4. One of the reasons why we age is the accumulation of proteins inside and outside cells. This protein accumulation is also called a “hallmark of aging” (R). Protein accumulation plays a role in Alzheimer’s disease (R), heart failure (R), blood vessel aging (R,R), and so on. A high-animal-protein diet can accelerate this process (R,R,R). Given that “protein accumulation” plays a major role in aging, following a “high protein diet” could accelerate this mechanism. 

5. One common thread throughout biogerontology (the science that studies aging) is that too much animal protein accelerates aging, reduces lifespan, and increases the risk of disease (R,R,R). 

Less Protein (and Less Macronutrients), Longer Lifespans 

6. In biogerontology, depriving animals of macronutrients like protein, sugar, and fats makes them live longer. This can be done, for example, via caloric restriction, fasting, or diets that lack essential amino acids (R,R,R). This suggests that doing the opposite, like consuming lots of amino acids and/or carbs, accelerates aging.  

7. Restricting protein extends lifespan (R,R,R).

8. Restricting essential amino acids extends lifespan, and increasing the intake of essential amino acids reduces lifespan (R,R,R,R). 

9. Restricting the amino acid methionine (essential for building proteins) extends lifespan (R,R,R,R). 

10. Many studies show that too much carbs, especially fast carbs, accelerate aging, for example by stimulating the insulin and IGF-1 pathways. Meat and animal protein also stimulates the insulin and IGF-1 and growth hormone pathways (R,R,R). 

Animal Protein Activates Aging Pathways  

11. Animal protein activates important “canonical” aging pathways. These are, for example, the mTOR, insulin, and the IGF-1 pathway. Activating these pathways by amino acids from animal protein accelerates aging. Meat and milk are strong activators of these pro-aging “nutrient sensing pathways,” and of other pro-aging pathways (e.g. galactose in milk) (R,R,R,R,R,R,R,R,R,R,R,R,R,R,R,R,R,R). 

12. Inhibiting the same aging pathways that meat and milk stimulate slows down aging (R,R,R).

13. mTOR is an important receptor (sensor) activated by amino acids from protein; mTOR activation reduces lifespan (R,R,R). 

14. Milk, a strong stimulator of aging pathways like mTOR, increases mortality and accelerates aging (R,R,R,R). 

15. Whey protein and branched chain amino acids strongly stimulate growth and aging pathways like mTOR (R). Giving animals whey protein makes them age and die faster than giving them equal amounts of soy protein (R). 

16. Taking substances (e.g., rapamycin) that inhibit aging pathways that animal protein stimulates (particularly, mTOR) extends lifespan (R). 

Meat, Animal Protein, and Growth

Diseases

17. Another common observation in all of biogerontology is that too much growth accelerates aging and increases the risk of aging-related diseases (R,R). Extra growth makes cells, including stem cells, wear out faster. Consuming a lot of animal protein promotes growth (e.g., of muscle mass). So in the short term, one feels better, but this activation of growth signaling accelerates aging. 

18. Meat or animal protein increases levels of growth hormone, IGF, and insulin, which are all known to accelerate aging and increase the risk of aging-related disease in the long term (R,R,R,R).  

19. People who suffer from diseases in which too much growth hormone is produced, like acromegaly, often die much sooner and suffer from various aging-related diseases at a young age. A high intake of meat also stimulates growth hormone, IGF (insulin-like growth factor), and insulin. 

20. Taking substances that promote (muscle) growth (e.g., growth hormone, IGF-1 inducers, testosterone boosters) have been associated with an increased risk of developing cancer, type 2 diabetes, heart disease, and other aging-related diseases. Animal protein also increases the body’s production of these same substances.

Accelerated Aging Vs. Living Longer

21. People with dwarfism due to a reduced activation of growth pathways (e.g., Laron syndrome) have less risk of developing aging-related diseases like cancer or type 2 diabetes (R). 

22. Induction of growth and “hyperfunction” is one of the central reasons why we age — see, for example, the papers of Mikhail Blagosklonny (R,R). 

23. Animals and people with mutations in the growth hormone, IGF, or insulin axis live longer and have fewer aging-related diseases (R). 

24. Scientists are developing therapies to slow aging by reducing growth hormone and growth pathways (e.g., via antibodies against growth hormone or via growth hormone inhibitors) (R). 

25. An important theory in aging, called “antagonistic pleiotropy,” states that specific advantages when being young can confer disadvantages (accelerate aging) when being older. For example, extra calcium uptake can enable stronger bones when one is young, but could accelerate calcification of the arteries in the long term.

Similarly, extra growth in the form of stronger muscles and more endurance and strength during youth/young age could accelerate aging in the long term, for example by too much activation of growth, IGF, and insulin pathways (R). 

Animal Protein and Cell Maintenance 

26. Too much protein (amino acids) gives the signal to the cells that they should not maintain themselves properly. The cells interpret an overabundance of amino acids (and sugars) as there are enough building blocks and energy to build new cell parts, so they maintain the existing parts less. The result is autophagy and other maintenance pathways are dialed down, which accelerates aging. 

27. Various pathways that are associated with extended healthspan and lifespan are based on being better able to cope with the effects of too much protein. For example, increased autophagy (the process that breaks down cellular proteins) increases lifespan (R). 

28. Activating autophagy increases lifespan (R). An intake of animal protein reduces autophagy (R,R).

29. Branched chain amino acids (also popular among athletes and bodybuilders) accelerate aging (R), for example by stimulating mTOR and inhibiting autophagy. Putting animals on a life-long diet devoid of branched-chain amino acids can lead to longer lifespans (R). 

Meat, Testosterone, and Aging

30. High-animal-protein diets lead to more testosterone in males. Male sex hormones accelerate aging (R,R). This makes sense in light of aging theories like the disposable soma theory of aging (Professor Kirkwood) and theory of antagonistic pleiotropy, in which sex and more strength during youth (early reproductive age) are tradeoffs that can accelerate aging in the long term (post-youth).

If animals get extra testosterone, they age and die faster (R). People who are castrated (their testes have been removed so they don’t make sex hormones like testosterone) live on average 14 to 19 years longer (R,R,R,R). Castrating animals also extends their lifespan (R,R,R). Giving female hormones to male animals can extend lifespan (R).

Why Grass-Fed Meat Still Accelerates Aging

31. Often, meat proponents will claim that the studies showing detrimental effects of high meat consumption are biased because the meat is “grain fed” or contains too much antibiotics, growth hormone, etc. However, given that it’s true that grass-fed, antibiotic-free meat is somewhat healthier than industry-made meat, the main problem is that the meat still contains lots of amino acids that overstimulate aging/nutrient sensing and growth pathways, and thus accelerates aging in the long-term. 

Plant-Based Diet Vs. Animal-Based Diet Protein 

32. There are differences between plant-based protein and animal-based protein. For example, in studies in which rats were given equal amounts of protein, but one group received plant-based soy protein while the other group received animal-based whey protein, we see that the rats on soy protein live longer (R). Rats on the soy-protein diet had a median length of life of 844 days compared to 730 days for the rats on a casein-containing diet. The rats on the soy-protein diet were also considerably healthier (R,R). 

33. Animal protein contains more branched chain amino acids (which are strong stimulators of the aging switch mTOR) and other amino acids that activate aging and growth pathways (R,R,R). 

34. A decreased consumption of branched chain amino acids can improve metabolic health (R). 

35. A more plant-based diet is associated with lower levels of pro-aging proteins like IGF compared with meat-eaters (R). 

36. Replacing animal-based protein with more vegetable-based protein reduces the risk of various aging-related diseases and mortality in humans (R,R,R).

37. The higher the animal-to-plant protein ratio, the higher the mortality rate in humans (R,R,R,R,R). 

38. Many studies show that substituting animal protein with plant protein reduces mortality and the risk of various aging-related diseases (R). For example, substituting plant foods like legumes, nuts, or soy for red meat can reduce the risk of cardiovascular diseases (R). Substituting one serving of red meat with one serving of other foods (including fish, poultry, nuts, and legumes) each day was associated with a 7% to 19% lower mortality risk (R). 

“It’s Not the Protein That’s Unhealthy” 

39. Often, people say that it’s not the protein that makes too much meat unhealthy. However, it’s clear that too much protein stimulates nutrient-sensing pathways. For example, directly infusing protein into the blood immediately induces insulin resistance. (R,R,R,R).

40. Studies also show a correlation with protein intake in meat and the risk of, for example, type 2 diabetes. For example, for every 5% increase in protein intake (of total calories) there is a 20% higher risk of type 2 diabetes (R). This dose-response relationship (the higher the dose of proteins, the higher the risk of diabetes) suggests a causative relationship. Large studies also demonstrate a dose-response relationship between protein intake (between red meat, processed red meat, and animal protein and type 2 diabetes (R)). 

41. In people with insulin resistance and type 2 diabetes, there are excess levels of amino acids (R). 

42. Contrary to plant-based foods, red meat contains specific amino acids, like methionine and branched-chain amino acids (BCAA’s) that can accelerate aging (R). 

43. Not only too many carbs but also too many amino acids play a role in type 2 diabetes (R). 

44. Too much meat intake alters the microbiome, which can accelerate aging and increase the risk of cancer and other aging-related diseases. The amino acids (protein) in meat leads to microbiome changes. Also, only partial digestion of meat protein in the gut can lead to unhealthy effects and an increased risk of autoimmune diseases (R,R). 

Other Things Besides Protein That Make Meat Unhealthy 

45. Red meat, often baked or barbecued, contains lots of substances that are unhealthy, like heterocyclic amines (HAs) and polycyclic aromatic hydrocarbons (PAHs). 

46. Fats in meat can directly activate white blood cells and lead to more inflammation (R,R,R). Meat-based fats are also more difficult for our cells to process and break down compared to plant-based meats, leading to the formation of free radicals and other unhealthy compounds inside cells (R,R,R). 

“But Wait, There Are Studies Showing That Meat Is Healthy”

47. Carnivore dieters often cite studies claiming that meat is healthy. For instance, they may refer to research where individuals replaced carbohydrates with lean red meat and experienced “reduced inflammation (R).

However, in this study, inflammation is measured in a very crude way (e.g., looking at CRP, instead of ultra-sensitive CRP). There are many other biomarkers of inflammation they didn’t look at in these studies that could have increased (IL-8, IL-6, IL-1, TNF-alpha, sedimentation rate, etc). 

Many biomarkers are actually crude ways to measure something like immune function or cardiovascular health. 

Moreover, these studies often fail to consider the long-term effects: does consuming large amounts of meat accelerate aging and lead to a shorter lifespan? It’s important to remember that many interventions or drugs can reduce inflammation while still decreasing lifespan, which ties into the concept of antagonistic pleiotropy.

Additionally, in many of these studies, participants reduce their consumption of junk food, fast sugars, and increase healthy fats, all of which can also lower inflammation. Rather than replacing fast carbs with animal protein, a better approach would be to swap fast carbs for vegetables, legumes, and mushrooms, which are more effective at reducing inflammation than red meat.

Lastly, for every study suggesting that red meat doesn’t increase inflammation or cancer risk, there are numerous others showing that meat consumption raises inflammation, cancer risk, and the likelihood of various diseases.

That said, plant-based or vegetarian diets also have their own potential drawbacks.

Challenges of Vegetarian and Plant-Based Diets 

We also understand why some paleo diet proponents are very opposed to a plant-based or vegetarian diet. 

After all, people who follow a plant-based or vegetarian diet can undermine their health or have a reduced quality of life. 

There are several reasons for this.

Deficiency in Key Micronutrients

One important reason is that they have more risk of micronutrient deficiencies. 

Examples of common micronutrient deficiencies when following a plant-based diet include iron, zinc, copper, carnosine, choline, iodine, phosphatidylcholine, various B vitamins (not only vitamin B12), (animal-based) omega-3 fatty acids (in case they also don’t eat fish), animal-based vitamin A (retinoids), calcium (often even when also drinking calcium-enriched plant-based milk), creatine (which confers longevity benefits), and so on. 

Just taking a multivitamin won’t suffice in most cases, given most multivitamins are inadequately dosed, do not include all micronutrients, contain the wrong forms of vitamins and minerals, or the plant-based forms are not properly converted into the animal forms (e.g., carotenoids into retinoids or ALA omega-3s into DHA and EPA), as we explain here.

This also explains why quite a lot of people following a vegetarian diet can suffer from fatigue, brain fog, trouble concentrating, difficulty finding words, slower thinking, anemia, looking pale, premature baldness, weakness, shortness of breath, reduced immunity (getting sick easily), and so on. 

Inadequate Protein

Furthermore, when following a plant-based diet, some people often do not take in enough protein. Yes, we just went over all of the issues from consuming too much protein, or a diet heavy in animal proteins, but the opposite can also become an issue: inadequate protein. 

This can lead to fatigue, weakness, dizziness, getting sick easily, and so on. It can also result in osteoporosis, sarcopenia and death from either cause in the later decades of life. Too much animal protein can accelerate aging, but too little protein is also not ideal. 

What We Believe Is The Best Diet for Longevity

We are proponents of a diet that is somewhat in the middle: we advise consuming a more plant-based diet, supplementing it with important health supplements and longevity supplements, as well as fatty fish, poultry, and hemp or a vegetarian blend of protein powder. 

This does not mean you can’t eat meat, we only recommend eating less meat. If you do eat animal foods, try to replace red meat (pork, beef, mutton) with white meat, fatty fish and organ meats. 

Don’t drink milk, but do make sure to take in adequate amounts of calcium. 

Replace bread, potatoes, pasta, and rice (which can also cause high sugar and insulin peaks) with vegetables, legumes, and mushrooms. Legumes and mushrooms also contain vegetable protein, just like nuts and seeds. 

Consider integrating fasting or time restricted feeding into your routine.

For a more complete description of the ideal diet for optimal healthspan and lifespan, check out the NOVOS longevity diet. 

Understand Carnivore Diet Pros and Cons

People often have strong opinions about diet.

They often follow other “experts” who confirm what they already believe, while not looking into or assigning adequate weight to other knowledge that shows otherwise. 

An important reason why the debate is still raging about animal- versus plant-based diets is that most diets do not approach nutrition from the viewpoint of aging and the effects that aging can have on health and disease risk.

Additionally, most diets look at short-term benefits like weight loss or improved biomarkers. They don’t look at how these diets impact important aging mechanisms and the long-term consequences thereof. 

If you look at the science of aging, it’s clear that overstimulation by nutrients like proteins (and glucose) accelerate aging. 

Our goal is to provide more clarity and information on this issue, approaching it from novel angles. 

Our approach is quite rare in the diet landscape, given we approach this issue from the viewpoint of aging. We also look at the long-term effects of nutrition while basing ourselves on the whole body of scientific studies, not just the ones that confirm our viewpoint. 

Our goal at NOVOS is to slow down aging, and we are agnostic to the approach. We rely on science to guide us and update our perspectives as new evidence is published.

We nonetheless recommend you do your own research. We strongly promote critical thinking. 

You can go to Pubmed (the largest database of scientific papers) and search terms like protein, animal-based diets, biogerontology, aging, mTOR, nutrient sensing pathways, autophagy, protein accumulation, and hallmark of aging, and read the many papers written about these topics.

FAQ About Plant-Based Diet Vs. Animal-Based Diet

Is the carnivore diet good for longevity?

Short term, it can boost energy and reduce inflammation. But in the long term, high meat intake accelerates aging by activating growth pathways and increasing disease risk.

What are the pros and cons of a plant-based diet?

Pros: longer lifespan, lower inflammation, better metabolic health. Cons: risk of nutrient deficiencies (e.g., B12, omega-3s) without smart supplementation.

Which is healthier: plant-based or animal-based?

Plant-based diets are linked to better longevity. Small amounts of fish or poultry can be beneficial, but heavy meat intake shortens lifespan in most studies.

Does high protein slow aging?

Not necessarily. You need enough protein to maintain muscle. But too much can speed up aging, especially protein from animal sources. Aim for moderation.

Why limit meat if it has nutrients?

Because meat overstimulates aging pathways like mTOR and IGF-1. Even grass-fed meat can promote inflammation and cellular aging over time.

What’s the best diet for longevity?

A mostly plant-based diet with some fish or poultry, low in starch and processed food, plus smart supplementation. This approach supports healthspan and lifespan. Explore The NOVOS Longevity Diet.