Can Eating Only Meat Be Healthier? The Pros and Cons of the Paleo Diet
Paul Saladino is a popular American nutrition influencer with millions of followers. According to his personal website, he is a medical doctor who completed his residency at the University of Washington in Seattle and is also a certified Physician Nutrition Specialist. During his medical training, he became disillusioned with the Western healthcare system's approach, which he felt only addressed symptoms rather than the root causes of health issues. Driven by a belief in the power of diet to help people achieve healthier lives, he created a personal social media platform where he fervently advocates for a meat-based and organ meat-focused diet.
In 2020, Saladino published The Carnivore Code, a book that presents evidence from scientific literature on the health benefits of eating meat, showcases the medical potential of an all-meat diet, and includes a carnivore-friendly recipe guide. The book quickly gained attention, with many influencers, Hollywood actors, athletes, and even political figures adopting the carnivore diet.
The diet Saladino advocates for can be classified as a variation of the "Paleo Diet," which is based on the idea of following the eating habits of humans from the Paleolithic era. Past research suggests that early humans primarily ate meat, and the rationale behind this diet is simple: humans evolved eating the diet of their ancestors, and our genes have not yet had enough time to adapt to modern agricultural products. However, Saladino's version of this diet is one of the more extreme forms, consisting solely of organ meats and grass-fed beef, while completely eliminating fruits and vegetables. He also claims that this way of eating cured his asthma and severe eczema. Saladino's slogan is, "If you eat like our ancient ancestors did millions of years ago, humanity will thrive!"
But the question remains: Can these popular celebrity-endorsed diets truly make us healthier?
--------------------------
The Real "Paleo Diet"
The "Paleo Diet" is modeled after the diet of our ancestors who lived during the Paleolithic era (approximately 2.6 million to 12,000 years ago), but the question is: Did they really eat mostly meat? What did early humans actually eat?
During the late Eocene to early Miocene epochs, primates, including humans, monkeys, and apes, evolved a fruit-based diet. The earliest human ancestors, part of the Hominina lineage, date back to around 6 to 7 million years ago. Fossil evidence shows that they had already learned to walk upright but spent a considerable amount of time in trees and did not yet use tools. Scientists hypothesize that their diet was likely very similar to that of our closest living relatives—the chimpanzees and bonobos, which are omnivores with a diet that includes a lot of fruit, leaves, flowers, and bark.
Around 3.5 million years ago, early hominids like Australopithecus afarensis and Kenyanthropus platyops began to expand their diet. In addition to plants, they also started eating animals. Archaeologists have found mammal bone fragments at the Dikika site in Ethiopia’s Afar region, which show signs of cutting and striking. These marks are believed to be from the only hominid species living in the area at the time—Australopithecus afarensis—indicating that they had learned to use stone tools. This discovery is one of the earliest pieces of evidence that humans began incorporating meat into their diets.
Evolutionary biologists believe that eating meat was crucial for the development of larger brains in our ancestors. Meat and bone marrow, as high-calorie food sources, provided energy for our ancestors' larger brains, unlike the low-calorie, plant-based foods consumed by other primates. Leslie Aiello, a professor of anthropology at University College London, and Peter Wheeler, a paleoanthropologist at Liverpool John Moores University, proposed that the human brain consumes 20% of the body’s total energy at rest, compared to just 8% in primates. This suggests that from the time of early Homo species, our ancestors relied heavily on high-energy foods, especially meat. Moreover, the digestion of high-calorie foods and the reduction of fiber-rich foods likely led to the evolution of smaller intestines, and the energy saved by smaller guts could be directed toward the brain. Additionally, animal-based foods allowed early humans to grow larger in size while maintaining agility and social attributes.
--------------------------
In addition, archaeological evidence also supports the continuation of meat-eating habits in humans. Research by Briana Pobiner, an anthropologist at the Smithsonian Institution’s National Museum of Natural History, and her colleagues suggests that early humans began consuming large animals more frequently and consistently over 2 million years ago. Archaeologists discovered an early human "meat butchering site" at the Kanjera South site in southern Kenya. Ancestors transported stones from more than ten kilometers away to create stone tools, then butchered animals they hunted or scavenged. The sediment layers left behind are over 3 meters thick, indicating that meat butchering occurred over multiple generations.
In addition to land animals, archaeological excavations at Koobi Fora in Kenya show that, from about 1.95 million years ago, early humans incorporated aquatic animals like turtles, crocodiles, and fish into their diet. Various archaeological sites in Tanzania’s Olduvai Gorge, dating back to 1.8 million years ago, show evidence of butchering mammals ranging from hedgehogs to elephants. As the saying goes, "You eat what you live by"—land animals by the mountains, and sea animals by the coast.
Homo erectus is considered a key point in the evolution of human diet, as their brain and body gradually evolved toward modern humans. Many scholars attribute this to meat consumption, suggesting that eating meat played a crucial role in human evolution. Archaeological evidence supporting the idea of meat-eating in Homo erectus has dramatically increased, further supporting this theory. But can we conclude that early humans primarily ate meat and evolved as such?
The answer is not so straightforward. Firstly, butchering sites like those of Homo erectus in Kanjera are not universally found. Furthermore, analysis of the stone tools at the site reveals significant wear patterns from cutting plants and digging up roots, suggesting that meat was not the only food consumed by early humans in that area.
There is also a methodological bias in scientific research. A team led by W. Andrew Barr at George Washington University analyzed the evidence of human meat-eating in East Africa from 2.6 million to 1.2 million years ago. They found no consistent increase in meat consumption, arguing that the growing body of archaeological evidence was more likely a result of sampling bias—researchers are more focused on discoveries from this period rather than earlier human diets.
-------------------
Jessica Thompson's team at Yale University believes that before humans invented tools suitable for hunting large animals, they may have used simple tools to extract nutrient-rich bone marrow and brain tissue from animal carcasses. The goal of early humans may have been to obtain fat rather than lean meat (as we typically think of today)ent humans, metabolizing wild animal lean meat required more energy, and without sufficient fat in their diet, they could easily suffer from protein poisoning or other health issues.
While early humans obtained animals through hunting or scavenging, they did not always have meat to eat. The Hadza and Kung of Africa, who are among the last groups to maintain a hunting-gathering lifestyle, may return empty-handed more than half of the time, even though they are well-armed today. This was even more true for early humans over 2 million years ago, who had no weapons and only rudimentary tools. As paleoanthropologist Alison Brooks humorously pointed out, "Antelopes on the African plains don't just stand around every day waiting to be hunted."
So, when hunters returned empty-handed, women and child gatherers provided more calorie-dense foods. The Hadza of Africa get nearly 70% of their calories from plant sources; the Kung rely on tubers, mangoes, and nuts; the Aka and Baka Pygmies of the Congo River Basin depend on yams. In the Amazon, the Tsimane and Yanomami Indians eat plantain and manioc, while Australian Aboriginals have a diet that includes bush tucker like bush onion and yams.
The teeth of ancient humans also provide important clues about what they ate. The morphological characteristics of human teeth reveal that our ancestors' diets were not limited to meat. Professor Lee Berger’s team at the University of the Witwatersrand in South Africa analyzed the wear patterns on the teeth of two Australopithecus sediba individuals and found tiny plant silica particles on the teeth. Through carbon isotope analysis, the team learned that the foods early humans chewed included tree bark, shrubs, leaves, and papyrus .
A pape in Nature Ecology & Evolution in April 2024 analyzed the enamel of late Stone Age hunter-gatherers in North Africa and found that their primary source of protein was plants, not meat. This challenges the view that pre-agricultural human groups were highly dependent on animal meat for protein . In other words, mtion alone did not shape humanity.
Peter Ungar, an anthropologist and evolutionary biologist at the University of Arkansas, explains that the teeth of Australopithecus were relatively large and flat, with a thick layer of enamel, indicating that they were adapted to chewing hard foods like seeds and nuts, and their teeth functioned to grind these substances. In contrast, Homo sapiens evolved smaller teeth with tooth shapes suited for eating tough foods. However, unlike other carnivores, we lack sharp canine teeth required to pierce and tear prey, as well as carnassial teeth used for cutting meat. Ungar proposes that we are not purely carnivorous, and our teeth did not evolve solely for meat consumption.
Modern "Paleo Diet"
As we can see, the dietary patterns of early humans uncovered by archaeologists do not entirely align with the modern "meat-based" paleo diet widely promoted on social media today. So, how did this celebrity-endorsed diet gain popularity?
The concept of the "Paleo Diet" was first introduced by American gastroenterologist Walter Voegtlin in the mid-1970s. He suggested that following a diet similar to that of Paleolithic humans could significantly improve the health of modern people (mainly Westerners). Voegtlin published The Stone Age Diet, emphasizing that early humans were primarily meat eaters, consuming animal proteins and fats with small amounts of carbohydrates. Based on his personal therapeutic experiences, Voegtlin found that individuals who followed this diet reported considerable health benefits.
In 1988, a research team composed of doctors and anthropologists compared the living environments and diets of modern humans with those of their prehistoric ancestors, ultimately publishing The Paleolithic Prescription: A Program of Diet and Exercise and a Design for Living. The book argued that people should emulate the nutrient intake ratios of late Stone Age ancestors, avoiding foods that were unavailable before the advent of agricultural civilization.
In 1989, Swedish doctor Staffan Lindeberg led a famous series of studies known as the Kitava Study. Kitava is an island in Papua New Guinea where the population primarily consumes natural foods such as tubers, fruits, fish, and coconuts, maintaining a lifestyle unaffected by modern industrial dietary habits. The study found that the local people not only had low rates of cardiovascular disease but also showed a near absence of common Western diseases like stroke and ischemic heart disease. Researchers attributed these findings to their adherence to a paleo-style diet. The Kitava Study became a key scientific foundation for doctors and nutritionists advocating for the paleo diet.
-------------------
Since the 1990s, more doctors and nutritionists have advocated for the revival of the so-called Paleolithic diet. In 2002, American nutritionist and exercise physiologist Loren Cordain published the bestselling book The Paleo Diet, which became one of the mainstream healthy eating approaches. The author emphasized the importance of fresh, unprocessed foods such as lean meats, fish, vegetables, and nuts, while recommending strict limitations on the intake of carbohydrates, grains, dairy products, sugar, and salt, particularly processed foods produced by the modern food industry【20】. From 2010 to the early 2020s, the promotion of the Paleo diet became increasingly commercialized, with many celebrities endorsing it. According to the private website Ultimate Paleo Guide【21】, NBA star LeBron James once challenged himself to follow the Paleo diet with a roommate during the off-season for two months, achieving some weight loss results. However, his coach supervised his return to a normal diet during the season【22】. In 2023, American actress Gwyneth Paltrow shared her eating habits in a podcast. After struggling with post-COVID inflammation, she adhered to the Paleo diet for an extended period on the advice of her doctor, experiencing significant anti-inflammatory effects【23】. However, an opinion piece published in The Guardian criticized this behavior as strange and extreme【24】. These cases thus seem more like marketing tactics leveraging celebrity influence.
Gwyneth Paltrow shares her grain-free, dairy-free, vegetable-free Paleo-style dinner on social media. Source: Instagram
Health Benefits of the Paleo Diet
So, do the short-term and long-term health effects of the Paleo diet truly live up to the hype, offering benefits for the general public with no drawbacks?
---------
First of all, if weight loss is the goal, there is scientific evidence to suggest that the Paleo diet can be somewhat effective.
In 2020, a team from the University of Otago in New Zealand conducted a comparative study of 250 overweight individuals to assess the weight loss effects of the Paleo diet, intermittent fasting, and the Mediterranean diet【26】. The researchers found that in the short term (6 months), the Paleo diet had a significant advantage in weight loss because the low-carbohydrate nature of the diet provided greater satiety, leading to faster weight loss【27】. However, at the end of a 12-month weight loss trial, while all three groups had lost weight, the Paleo diet was the least effective. On average, participants on the Paleo diet lost around 3.6 kilograms, those on the Mediterranean diet lost 5.5 kilograms, and those on intermittent fasting lost about 8 kilograms. According to participant feedback, the Mediterranean diet was the easiest to stick with among the three.
In another earlier 2-year randomized trial【28】, researchers tracked 70 overweight Swedish women and assigned one group to follow the Paleo diet long-term, while another group adhered to the Nordic Nutrition Recommendations (NNR), which involved consuming less protein and fat, and more carbohydrates than the Paleo diet. After 6 months, participants on the Paleo diet lost more weight compared to those on the NNR diet, with the former losing an average of 12 kilograms, while the latter lost about 4.5 kilograms. However, after 24 months, the weight loss results were nearly identical in both groups. Additionally, both groups saw significant improvements in blood pressure and cholesterol levels. Notably, those following the Paleo diet had a greater reduction in triglyceride levels, which is associated with a lower risk of heart disease.
In the 2010s, when the Paleo diet became popular, a small study analyzed the possible relationship between the Paleo diet and cancer【29】. Colorectal cancer, the third most common cancer in the U.S., is associated with the Western dietary pattern. The researchers conducted a controlled analysis with patients who had colorectal polyps, showing that strictly following both the Paleo diet and the Mediterranean diet helped reduce the risk of colorectal cancer. However, this study was focused on a specific population, and participants' actual diets may not have perfectly adhered to the Paleo or Mediterranean diets, so while the results are informative, further investigation is needed.
Scientists are particularly concerned with the long-term effects of maintaining the Paleo diet. A study led by Professor Angela Genoni from Edith Cowan University in Australia【30】 examined the impact of following the Paleo diet for more than a year. The study involved an experimental group of 44 participants who adhered to the Paleo diet, eating grains and dairy no more than once a day, and a control group of 48 people who maintained a balanced diet. The results were surprising: compared to the control group, those on the Paleo diet showed unfavorable changes in their gut microbiota composition after 1 year. Specifically, there was an increase in the abundance of Hungatella species, which produces higher levels of trimethylamine-N-oxide (TMAO) during the digestion of meat. TMAO has been molecularly linked to promoting atherosclerosis and blood clot formation, and is associated with an increased risk of cardiovascular disease.
So, how to eat well?
Based on the existing research, there are some reasonable aspects to the Paleo diet, such as its emphasis on reducing or even avoiding industrially processed foods, which aligns with the health principles many people pursue. (Processed meats have been classified as a Group 1 carcinogen by the International Agency for Research on Cancer, a part of the World Health Organization.) However, each person's body, living environment, and lifestyle are different, so there is no perfect diet that works for everyone. Therefore, if one follows the Paleo diet purely due to celebrity influence, it could have some negative long-term effects on health.
The best approach might be to avoid extremes and understand the strengths and weaknesses of each dietary approach. The Paleo diet provides a dietary template, but after proper consultation with nutrition experts, we can develop the eating principles and patterns that best suit our individual needs.
Additionally, this year, Saladino announced that for personal health reasons, he would abandon the strict Paleo diet he had been following and reintroduce carbohydrates and dairy products. He has now proposed a so-called "carnivore diet," but his primary goal remains the same: everything is for the sake of health.
In 2020, Saladino published The Carnivore Code, a book that presents evidence from scientific literature on the health benefits of eating meat, showcases the medical potential of an all-meat diet, and includes a carnivore-friendly recipe guide. The book quickly gained attention, with many influencers, Hollywood actors, athletes, and even political figures adopting the carnivore diet.
The diet Saladino advocates for can be classified as a variation of the "Paleo Diet," which is based on the idea of following the eating habits of humans from the Paleolithic era. Past research suggests that early humans primarily ate meat, and the rationale behind this diet is simple: humans evolved eating the diet of their ancestors, and our genes have not yet had enough time to adapt to modern agricultural products. However, Saladino's version of this diet is one of the more extreme forms, consisting solely of organ meats and grass-fed beef, while completely eliminating fruits and vegetables. He also claims that this way of eating cured his asthma and severe eczema. Saladino's slogan is, "If you eat like our ancient ancestors did millions of years ago, humanity will thrive!"
But the question remains: Can these popular celebrity-endorsed diets truly make us healthier?
--------------------------
The Real "Paleo Diet"
The "Paleo Diet" is modeled after the diet of our ancestors who lived during the Paleolithic era (approximately 2.6 million to 12,000 years ago), but the question is: Did they really eat mostly meat? What did early humans actually eat?
During the late Eocene to early Miocene epochs, primates, including humans, monkeys, and apes, evolved a fruit-based diet. The earliest human ancestors, part of the Hominina lineage, date back to around 6 to 7 million years ago. Fossil evidence shows that they had already learned to walk upright but spent a considerable amount of time in trees and did not yet use tools. Scientists hypothesize that their diet was likely very similar to that of our closest living relatives—the chimpanzees and bonobos, which are omnivores with a diet that includes a lot of fruit, leaves, flowers, and bark.
Around 3.5 million years ago, early hominids like Australopithecus afarensis and Kenyanthropus platyops began to expand their diet. In addition to plants, they also started eating animals. Archaeologists have found mammal bone fragments at the Dikika site in Ethiopia’s Afar region, which show signs of cutting and striking. These marks are believed to be from the only hominid species living in the area at the time—Australopithecus afarensis—indicating that they had learned to use stone tools. This discovery is one of the earliest pieces of evidence that humans began incorporating meat into their diets.
Evolutionary biologists believe that eating meat was crucial for the development of larger brains in our ancestors. Meat and bone marrow, as high-calorie food sources, provided energy for our ancestors' larger brains, unlike the low-calorie, plant-based foods consumed by other primates. Leslie Aiello, a professor of anthropology at University College London, and Peter Wheeler, a paleoanthropologist at Liverpool John Moores University, proposed that the human brain consumes 20% of the body’s total energy at rest, compared to just 8% in primates. This suggests that from the time of early Homo species, our ancestors relied heavily on high-energy foods, especially meat. Moreover, the digestion of high-calorie foods and the reduction of fiber-rich foods likely led to the evolution of smaller intestines, and the energy saved by smaller guts could be directed toward the brain. Additionally, animal-based foods allowed early humans to grow larger in size while maintaining agility and social attributes.
--------------------------
In addition, archaeological evidence also supports the continuation of meat-eating habits in humans. Research by Briana Pobiner, an anthropologist at the Smithsonian Institution’s National Museum of Natural History, and her colleagues suggests that early humans began consuming large animals more frequently and consistently over 2 million years ago. Archaeologists discovered an early human "meat butchering site" at the Kanjera South site in southern Kenya. Ancestors transported stones from more than ten kilometers away to create stone tools, then butchered animals they hunted or scavenged. The sediment layers left behind are over 3 meters thick, indicating that meat butchering occurred over multiple generations.
In addition to land animals, archaeological excavations at Koobi Fora in Kenya show that, from about 1.95 million years ago, early humans incorporated aquatic animals like turtles, crocodiles, and fish into their diet. Various archaeological sites in Tanzania’s Olduvai Gorge, dating back to 1.8 million years ago, show evidence of butchering mammals ranging from hedgehogs to elephants. As the saying goes, "You eat what you live by"—land animals by the mountains, and sea animals by the coast.
Homo erectus is considered a key point in the evolution of human diet, as their brain and body gradually evolved toward modern humans. Many scholars attribute this to meat consumption, suggesting that eating meat played a crucial role in human evolution. Archaeological evidence supporting the idea of meat-eating in Homo erectus has dramatically increased, further supporting this theory. But can we conclude that early humans primarily ate meat and evolved as such?
The answer is not so straightforward. Firstly, butchering sites like those of Homo erectus in Kanjera are not universally found. Furthermore, analysis of the stone tools at the site reveals significant wear patterns from cutting plants and digging up roots, suggesting that meat was not the only food consumed by early humans in that area.
There is also a methodological bias in scientific research. A team led by W. Andrew Barr at George Washington University analyzed the evidence of human meat-eating in East Africa from 2.6 million to 1.2 million years ago. They found no consistent increase in meat consumption, arguing that the growing body of archaeological evidence was more likely a result of sampling bias—researchers are more focused on discoveries from this period rather than earlier human diets.
-------------------
Jessica Thompson's team at Yale University believes that before humans invented tools suitable for hunting large animals, they may have used simple tools to extract nutrient-rich bone marrow and brain tissue from animal carcasses. The goal of early humans may have been to obtain fat rather than lean meat (as we typically think of today)ent humans, metabolizing wild animal lean meat required more energy, and without sufficient fat in their diet, they could easily suffer from protein poisoning or other health issues.
While early humans obtained animals through hunting or scavenging, they did not always have meat to eat. The Hadza and Kung of Africa, who are among the last groups to maintain a hunting-gathering lifestyle, may return empty-handed more than half of the time, even though they are well-armed today. This was even more true for early humans over 2 million years ago, who had no weapons and only rudimentary tools. As paleoanthropologist Alison Brooks humorously pointed out, "Antelopes on the African plains don't just stand around every day waiting to be hunted."
So, when hunters returned empty-handed, women and child gatherers provided more calorie-dense foods. The Hadza of Africa get nearly 70% of their calories from plant sources; the Kung rely on tubers, mangoes, and nuts; the Aka and Baka Pygmies of the Congo River Basin depend on yams. In the Amazon, the Tsimane and Yanomami Indians eat plantain and manioc, while Australian Aboriginals have a diet that includes bush tucker like bush onion and yams.
The teeth of ancient humans also provide important clues about what they ate. The morphological characteristics of human teeth reveal that our ancestors' diets were not limited to meat. Professor Lee Berger’s team at the University of the Witwatersrand in South Africa analyzed the wear patterns on the teeth of two Australopithecus sediba individuals and found tiny plant silica particles on the teeth. Through carbon isotope analysis, the team learned that the foods early humans chewed included tree bark, shrubs, leaves, and papyrus .
A pape in Nature Ecology & Evolution in April 2024 analyzed the enamel of late Stone Age hunter-gatherers in North Africa and found that their primary source of protein was plants, not meat. This challenges the view that pre-agricultural human groups were highly dependent on animal meat for protein . In other words, mtion alone did not shape humanity.
Peter Ungar, an anthropologist and evolutionary biologist at the University of Arkansas, explains that the teeth of Australopithecus were relatively large and flat, with a thick layer of enamel, indicating that they were adapted to chewing hard foods like seeds and nuts, and their teeth functioned to grind these substances. In contrast, Homo sapiens evolved smaller teeth with tooth shapes suited for eating tough foods. However, unlike other carnivores, we lack sharp canine teeth required to pierce and tear prey, as well as carnassial teeth used for cutting meat. Ungar proposes that we are not purely carnivorous, and our teeth did not evolve solely for meat consumption.
Modern "Paleo Diet"
As we can see, the dietary patterns of early humans uncovered by archaeologists do not entirely align with the modern "meat-based" paleo diet widely promoted on social media today. So, how did this celebrity-endorsed diet gain popularity?
The concept of the "Paleo Diet" was first introduced by American gastroenterologist Walter Voegtlin in the mid-1970s. He suggested that following a diet similar to that of Paleolithic humans could significantly improve the health of modern people (mainly Westerners). Voegtlin published The Stone Age Diet, emphasizing that early humans were primarily meat eaters, consuming animal proteins and fats with small amounts of carbohydrates. Based on his personal therapeutic experiences, Voegtlin found that individuals who followed this diet reported considerable health benefits.
In 1988, a research team composed of doctors and anthropologists compared the living environments and diets of modern humans with those of their prehistoric ancestors, ultimately publishing The Paleolithic Prescription: A Program of Diet and Exercise and a Design for Living. The book argued that people should emulate the nutrient intake ratios of late Stone Age ancestors, avoiding foods that were unavailable before the advent of agricultural civilization.
In 1989, Swedish doctor Staffan Lindeberg led a famous series of studies known as the Kitava Study. Kitava is an island in Papua New Guinea where the population primarily consumes natural foods such as tubers, fruits, fish, and coconuts, maintaining a lifestyle unaffected by modern industrial dietary habits. The study found that the local people not only had low rates of cardiovascular disease but also showed a near absence of common Western diseases like stroke and ischemic heart disease. Researchers attributed these findings to their adherence to a paleo-style diet. The Kitava Study became a key scientific foundation for doctors and nutritionists advocating for the paleo diet.
-------------------
Since the 1990s, more doctors and nutritionists have advocated for the revival of the so-called Paleolithic diet. In 2002, American nutritionist and exercise physiologist Loren Cordain published the bestselling book The Paleo Diet, which became one of the mainstream healthy eating approaches. The author emphasized the importance of fresh, unprocessed foods such as lean meats, fish, vegetables, and nuts, while recommending strict limitations on the intake of carbohydrates, grains, dairy products, sugar, and salt, particularly processed foods produced by the modern food industry【20】. From 2010 to the early 2020s, the promotion of the Paleo diet became increasingly commercialized, with many celebrities endorsing it. According to the private website Ultimate Paleo Guide【21】, NBA star LeBron James once challenged himself to follow the Paleo diet with a roommate during the off-season for two months, achieving some weight loss results. However, his coach supervised his return to a normal diet during the season【22】. In 2023, American actress Gwyneth Paltrow shared her eating habits in a podcast. After struggling with post-COVID inflammation, she adhered to the Paleo diet for an extended period on the advice of her doctor, experiencing significant anti-inflammatory effects【23】. However, an opinion piece published in The Guardian criticized this behavior as strange and extreme【24】. These cases thus seem more like marketing tactics leveraging celebrity influence.
Gwyneth Paltrow shares her grain-free, dairy-free, vegetable-free Paleo-style dinner on social media. Source: Instagram
Health Benefits of the Paleo Diet
So, do the short-term and long-term health effects of the Paleo diet truly live up to the hype, offering benefits for the general public with no drawbacks?
---------
First of all, if weight loss is the goal, there is scientific evidence to suggest that the Paleo diet can be somewhat effective.
In 2020, a team from the University of Otago in New Zealand conducted a comparative study of 250 overweight individuals to assess the weight loss effects of the Paleo diet, intermittent fasting, and the Mediterranean diet【26】. The researchers found that in the short term (6 months), the Paleo diet had a significant advantage in weight loss because the low-carbohydrate nature of the diet provided greater satiety, leading to faster weight loss【27】. However, at the end of a 12-month weight loss trial, while all three groups had lost weight, the Paleo diet was the least effective. On average, participants on the Paleo diet lost around 3.6 kilograms, those on the Mediterranean diet lost 5.5 kilograms, and those on intermittent fasting lost about 8 kilograms. According to participant feedback, the Mediterranean diet was the easiest to stick with among the three.
In another earlier 2-year randomized trial【28】, researchers tracked 70 overweight Swedish women and assigned one group to follow the Paleo diet long-term, while another group adhered to the Nordic Nutrition Recommendations (NNR), which involved consuming less protein and fat, and more carbohydrates than the Paleo diet. After 6 months, participants on the Paleo diet lost more weight compared to those on the NNR diet, with the former losing an average of 12 kilograms, while the latter lost about 4.5 kilograms. However, after 24 months, the weight loss results were nearly identical in both groups. Additionally, both groups saw significant improvements in blood pressure and cholesterol levels. Notably, those following the Paleo diet had a greater reduction in triglyceride levels, which is associated with a lower risk of heart disease.
In the 2010s, when the Paleo diet became popular, a small study analyzed the possible relationship between the Paleo diet and cancer【29】. Colorectal cancer, the third most common cancer in the U.S., is associated with the Western dietary pattern. The researchers conducted a controlled analysis with patients who had colorectal polyps, showing that strictly following both the Paleo diet and the Mediterranean diet helped reduce the risk of colorectal cancer. However, this study was focused on a specific population, and participants' actual diets may not have perfectly adhered to the Paleo or Mediterranean diets, so while the results are informative, further investigation is needed.
Scientists are particularly concerned with the long-term effects of maintaining the Paleo diet. A study led by Professor Angela Genoni from Edith Cowan University in Australia【30】 examined the impact of following the Paleo diet for more than a year. The study involved an experimental group of 44 participants who adhered to the Paleo diet, eating grains and dairy no more than once a day, and a control group of 48 people who maintained a balanced diet. The results were surprising: compared to the control group, those on the Paleo diet showed unfavorable changes in their gut microbiota composition after 1 year. Specifically, there was an increase in the abundance of Hungatella species, which produces higher levels of trimethylamine-N-oxide (TMAO) during the digestion of meat. TMAO has been molecularly linked to promoting atherosclerosis and blood clot formation, and is associated with an increased risk of cardiovascular disease.
So, how to eat well?
Based on the existing research, there are some reasonable aspects to the Paleo diet, such as its emphasis on reducing or even avoiding industrially processed foods, which aligns with the health principles many people pursue. (Processed meats have been classified as a Group 1 carcinogen by the International Agency for Research on Cancer, a part of the World Health Organization.) However, each person's body, living environment, and lifestyle are different, so there is no perfect diet that works for everyone. Therefore, if one follows the Paleo diet purely due to celebrity influence, it could have some negative long-term effects on health.
The best approach might be to avoid extremes and understand the strengths and weaknesses of each dietary approach. The Paleo diet provides a dietary template, but after proper consultation with nutrition experts, we can develop the eating principles and patterns that best suit our individual needs.
Additionally, this year, Saladino announced that for personal health reasons, he would abandon the strict Paleo diet he had been following and reintroduce carbohydrates and dairy products. He has now proposed a so-called "carnivore diet," but his primary goal remains the same: everything is for the sake of health.
Tags: