Carnivore Animal-Based vs Plant-Based Diets & Their Role in Aging (2024)

We have an ambitious goal.

In this article, we want to settle the animal-based versus plant-based diet debate.

We understand why many carnivore diet fans have strong opinions about plant-based diets, and why plant-based dieters sometimes vehemently oppose meat-based diets.

Both have some good points. And some bad points.

It’s remarkable, but also understandable, that quite a lot of people still think high-animal-protein or high-meat diets are healthy, in light of so much scientific evidence to the contrary.

On the other hand, plant-based diets also have various shortcomings, as we will explain.As you may have deduced, we suggest a balanced approach of both plants and a moderate amount of animal protein, if longevity and maximizing your health are your goals.

Why Should You Believe Us?

We approach this topic from a novel perspective: aging. If you better understand why we age, you can better assess the long-term effects of diets and foods.

Our view is that high-animal protein diets are unhealthy in the long term because a high meat intake accelerates fundamental aging processes (whether your meat is grass-fed and antibiotic-free or not).

However, a plant-based diet can also accelerate aging, in part because people have a high risk of becoming deficient in important nutrients (even when taking 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 Their Diet Is “Healthy”

Often fans of high-animal-protein diets, like the paleo diet, cavemen diet, carnivore diet, Atkins diet, or Dukan diet, feel very strongly about their way of eating; they think their diet is the best of all diets.

Some reasons why high-animal protein proponents often believe their diet is healthy are the following:

• People on a high-animal protein diet can feel great. They might feel stronger, have more energy, build more muscle, lose weight, improve insulin resistance, and so on. However, these are short-term effects. Looking at the long-term effects of high-animal-protein diets stretching over decades, it would be clear that this kind of diet accelerates aging and can increase the risk of aging-related diseases, including heart disease and cancer. (We’ll explain why below).

• Sometimes people on a high-animal-protein diet do not only feel better, but they can also improve specific diseases, such as autoimmune diseases like multiple sclerosis (MS) or rheumatoid arthritis. However, this is not so much because of the meat (as meat can be pro-inflammatory — see further below), but mainly because this diet can reduce inflammation via various other mechanisms. For example, when following high-animal-protein diets, people often substantially reduce their intake of pro-inflammatory sugars and refined carbs (by consuming less sugary and starchy foods like bread, potatoes, pasta, and rice — which we also recommend). They also eat less junk food, eat more vegetables, and consume more healthy, anti-inflammatory fats, while consuming fewer substances that can cause auto-immune diseases, like gluten, soy, or dairy. So in a certain way, a carnivore diet is also a restriction diet. However, given meat and various fats found in meat can also induce inflammation (R,R), reducing meat intake, combined with low-glycemic vegetables, legumes, mushrooms, and healthy fats, would be even more beneficial (see further below).

• Proponents of high-animal-protein diets are often not very knowledgeable about biogerontology, the science of aging. They are unfamiliar with the effects of high-animal-protein intake on important aging pathways and mechanisms.

• Sometimes, high-animal-protein diet proponents draw on their own experiences after first following a plant-based diet. Often, they felt worse on such a diet, which can indeed be the case since a more plant-based diet (especially a vegetarian or vegan diet) can cause deficiencies and other problems, as we will discuss later.

• High-animal-protein dieters mainly focus on studies and books that further support their view; they don’t read other studies and books that demonstrate that such diets are unhealthy in the long term. Nutrition science is very complicated and very extensive!

• Carnivore dieters assume that given people in prehistoric times ate a lot of meat, a high-meat-based diet is best for humans. There are two main flaws in this reasoning:

First, scientists don’t know if prehistoric people really ate a lot of meat; meat was often difficult to come by.

Second, even if prehistoric people ate a lot of meat, this does not mean it is healthy for longevity. Nature does not care about us living a long life: it mainly cares about people reproducing as soon as possible (teens and twenties). What happens after that is no worry for nature. In fact, that’s the reason why aging exists: to make room for the future evolutionary generations.

So even if people in prehistory consumed lots of meat and this increased their risk of getting a heart attack when they would be 60, this would not be a problem given most prehistoric people didn’t have the chance to get so old. They died of external causes of death (e.g., accidents, disease, violence, starvation, etc.).

As modern humans, however, we have another agenda that somewhat conflicts with evolution: we want to live a long and healthy life. Nature wants us to live a short and reproductively successful life; if eating a lot of meat helped with this goal, but accelerated aging in the long term, that would be aligned with evolution’s goals.

Plant-Based Versus Meat-Based (Carnivore) Diets

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 higher risk of deficiencies of vitamins and minerals on a plant-based diet.

However, we believe this can be even further improved upon.

The crux is to follow a diet with low-starch plants at the foundation, with modest amounts of animal protein (mostly fish, some poultry if you’d like; red meat should be on rare occasions if you so choose and ideally in the form of organ meats), and plant-based hemp protein powder and nutritional supplements that will fill in the inevitable gaps regardless of what diet you’re on: carnivore, vegan, Mediterranean, you name it.

So, in essence, whatever diet you choose, no diet is perfect. That’s why you need supplements and may elect to use specific forms of protein powders. Because as we explain here, nature does not create perfect solutions.

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See Also

Ultimate Guide to Uses & Benefits of Protein ShakesHow Much Protein Should I Eat a Day? | Protein Sources - Consumer ReportsEnsure vs. Premier Protein: Which Protein Shake is Best?Healthy Meal Planning: Tips for Older Adults

51 Scientific Arguments Why a High-Meat (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

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. 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).

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

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

23. 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.

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

Animal Versus Plant 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).

Anecdotal Evidence

45. People who eat a lot of animal protein often look considerably older for their age. They look “muscular and bulky,” but they often easily look 10 years older.

46. People who eat lots of animal protein often have a receding hairline or go bald because of the overstimulation of growth pathways, which depletes hair follicle stem cells (R). (However, premature baldness can also happen with vegetarian diets because of nutrient deficiencies, including protein deficiency — as we explain here). This also helps to explain why bodybuilders or people on a carnivore diet can become bald prematurely. Becoming bald early can be a symptom of accelerated aging, which also increases the risk of aging-related diseases (R).

47. People who follow a more plant-based diet often look younger for their age as long as they don’t overdo it (e.g., like some vegetarians becoming deficient in important nutrients).

48. Bodybuilders who take in large amounts of animal protein, growth hormone, and male hormones often die considerably younger and have a significantly higher risk of dying (R).

Other Things Besides Protein That Make Meat Unhealthy

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

50. 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”

51. Often, carnivorous dieters bring up studies “demonstrating” that meat is healthy. For example, they mention a study in which people replace carbs with lean red meat and have “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.

Furthermore, these kinds of studies don’t look at the long-term effects: if you eat a lot of meat, do you age and die faster? After all, there are many interventions or drugs that can reduce inflammation but still shorten lifespan. Recall the earlier referred- to concept of antagonistic pleiotropy.

Additionally, in many of these studies, people eat less junk food, less fast sugars, more healthy fats, etc., which can all also lead to less inflammation. Instead of replacing fast carbs with animal protein, it would be better to replace fast carbs with vegetables, legumes, and mushrooms, which will reduce inflammation far better compared to red meat.

Finally, for every study that “shows” that red meat does not increase inflammation or cancer risk, there are many more studies that do show that meat intake increases inflammation, cancer risk, and the risk of many other diseases.

However, plant-based or vegetarian diets can also have drawbacks.

Problems With 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. 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.

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.

Conclusion

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.

We hope this sheds some light. Please do not hesitate to send this article to your carnivore (or vegan) friends!