What is the Paleo diet, really – and should I try it?

By now, most people have heard of “the Paleo Diet”: it’s been a widely talked-about and researched dietary approach for some time. The concept of Paleo eating entered the nutrition conversation in the 1970s, but didn’t gain momentum until 2002 with the publication of Loren Cordain’s book, The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat. ^[1] In the years since, Paleo-style diets have been the focus of hundreds of books, scientific papers, and professional lectures, with an estimated 3 million people in the US alone adhering to its principles. ^[2]

Still, it’s understandable if you’re not completely clear on what the Paleo diet entails, and you might be wondering if there’s something truly useful and practical behind what some consider yet another fad diet. We’ll cut through the confusion, break down what the Paleo diet is all about, and look objectively at its effects on human health.

Why “Paleo”?

The Paleo diet draws inspiration from the dietary and environmental influences of the Paleolithic period—an era spanning from 2.5 million years ago to about 10,000 B.C.E., ending with the dawn of agriculture. It was during this time that our early ancestors became anatomically human, undergoing physiological changes as we adapted to different climates, began using stone tools, learned to control fire, and expanded our diet to include more diverse foods. ^[3] Historical analyses show that the diseases most common today—including heart disease—were extremely rare during this era. ^[4]

Throughout this period, early humans were mostly nomadic hunter-gatherers who subsisted on a variety of unprocessed foods that they were able to catch or forage. They ate a nutrient-dense array of plants and animals including ruminant meat, small mammals, birds, fish, shellfish, reptiles, vegetables, fruits, berries, tubers, roots, nuts, honey, insects, and whatever else the local environment provided.

Importantly, there was a complete absence of many of the foods and ingredients that dominate store shelves today—including grains, refined sugar, vegetable oils, processed dairy, chemical additives, artificial sweeteners, and preservatives.

As a result, the Paleo diet is a basic framework encompassing nutrient density, dietary diversity, whole-foods eating, and the avoidance of harmful modern allergens and food-like products.

Inspiration vs. reenactment

One of the common misconceptions about Paleo-style eating is that it’s based on historical reenactment—that is, trying to re-create the exact diet and lifestyle of Paleolithic humans. This is far from the case! Rather, the Paleo diet takes a big-picture approach to human nutritional needs, helping identify the features of the modern diet and lifestyle that are out of alignment with the human body’s design.

Ultimately, it’s impossible to eat the exact same vegetables, fruits, and animal species that our early ancestors did. Many Paleolithic era staples (such as megafauna like mammoths and mastodons) are now extinct, and thousands of years of evolution and cultivation have rendered today’s plant foods unrecognizable from what they were historically. And so, rather than implying we try to literally eat like cavemen, the Paleo diet suggests we look at the overarching dietary patterns our bodies spent millennia adapting to. In doing so, we find clues for what’s best for us today.

These broad dietary patterns include:

• High fiber intake
• High nutrient density (the ratio of micronutrients to total calories)
• A balanced omega-3/omega-6 fat ratio
• Low intake of allergenic and inflammatory foods
• High intake of nutrients and compounds promoting gut health
• Absence of ultra-processed and hyper-palatable food products

Importantly, these Paleo-inspired nutritional tenets are backed by modern science, with studies showing they individually and collectively protect against chronic diseases. These include:

• Cardiovascular disease ^[5] [6]
• Stroke ^[7]
• Cancer ^[5]
• Obesity ^[8] [9]
• Metabolic syndrome ^[9]
• Alzheimer’s disease ^[10]
• Depression ^[11]
• Autoimmune disease ^[12]
• Asthma ^[12]
• Allergies ^[12]
• Osteoporosis ^[13]

To help avoid fixating on a specific era in history, or incorrectly conjuring images of caveman reenactment, terms like “ancestral eating” or “primal” are sometimes used to describe this way of eating. Likewise, some eating plans use ancestrally aligned principles without specifically calling themselves Paleo, such as the Whole30 Program.

So, what exactly does Paleo eating look like?

Although the Paleo diet is rooted in some core principles, in practice, it offers abundant flexibility and room for individual tailoring. As a starting place, it includes whole or minimally processed foods from the following categories:

• Vegetables
• Fruits and berries
• Meat (including organ meat)
• Seafood (including fish, shellfish, and crustaceans)
• Poultry
• Eggs
• Nuts and seeds
• Roots and tubers
• Honey and maple syrup
• Cold-pressed oils from botanical fruit (including olive, avocado, coconut, and palm)
• Animal fats (including tallow, lard, bacon fat, duck fat, and chicken fat)
• Nuts and most seeds
• Herbs and spices

In addition, some people choose to include “gray zone” foods that vary in their individual tolerance. These include:

• Coffee
• Wine
• High-quality dairy products

By contrast, a Paleo diet excludes:

• Grains (including whole grains)
• Legumes
• Processed dairy
• Soy products
• High omega-6 vegetable oils (including soybean oil, corn oil, canola oil, cottonseed oil, safflower oil, grapeseed oil, and margarines made with these oils)
• Refined sugar
• Artificial sweeteners
• Chemical additives and preservatives
• Food colorings

How much you eat of each Paleo-friendly food is up to you, but in general, striving for diversity of both plant and animal foods helps ensure a wide intake of different vitamins, minerals, and phytochemicals. An example of a Paleo plate would be some form of protein (eggs, fish, poultry, pork, or beef), a non-starchy green vegetable (such as leafy greens or broccoli), a healthy fat source (like an avocado, nuts, or olive oil), and a nutrient-dense carbohydrate food (like a sweet potato or fruit).

Individual tailoring

Some people further tailor their Paleo diet to fit additional nutritional needs—such as avoiding foods that trigger autoimmune reactions (per the Autoimmune Protocol), limiting high-FODMAP foods to help manage IBS, avoiding nuts or seafood due to allergies, eating within ketogenic ratios, and other modifications.

Likewise, some people strive to optimize food quality and sustainability by eating locally and seasonally, choosing organic or pesticide-free produce, and seeking out grass-fed or free-range animal products. While these are excellent goals with many benefits for both human health and the planet, they’re not mandatory for following a Paleo diet—especially if doing so makes eating Paleo impractical or financially untenable for your current situation.

In short, Paleo eating will look different for different people, as we all have our preferences, goals, and intolerances. Some of us will enjoy more carbs from fruits and roots, some of us will eat more or less red meat, and some of us might make Paleo pancakes on the weekends: these are all versions of Paleo eating!

Is the Paleo diet low carb?

The Paleo diet sometimes gets portrayed as a meat-heavy, low-carbohydrate diet, but in practice, this way of eating is “macronutrient agnostic”—meaning it can encompass a wide range of fat, carbohydrate, and protein intakes, as long as the foods being consumed fit into the general Paleo framework.

Part of the confusion comes from difficulty in assessing the plant food intake of early humans. Unlike the bones, shells, and other physical remains left after butchering animals, evidence of plant food consumption disintegrates quickly and leaves fewer traces. As a result, animal foods may be over-represented at archeological sites where Paleolithic humans lived, giving a false impression that ancestral eating should be meat-dominant and low-carb.

However, other forms of evidence (including human anatomical changes, dentition, and carbon isotope analyses) show that early humans were eating higher-carbohydrate foods like roots and tubers for hundreds of thousands of years, if not longer. ^[14] [15] Paleo diet reconstructions, based on food availability in East Africa, estimate that Paleolithic humans were getting about 40% of their energy from carbohydrates. ^[16] Likewise, modern hunter-gatherer populations—which scientists sometimes study for clues about pre-modernized diets—have a wide range of carbohydrate intakes, spanning from 3% to 50% of total energy. ^[17]

There’s also genetic evidence for humans adapting to starch consumption, through selective increases in the number of carbohydrate-degrading salivary amylase gene copies (AMY1) we carry relative to other primates. ^[18]

In short, there’s no explicit rule to keep carbohydrate levels in a certain range while following a Paleo diet; doing so is a matter of personal choice. The heart of Paleo is eating ancestrally aligned foods rather than tracking numbers!

Didn’t cavemen live short lives?

A common criticism of the Paleo diet is that compared to modern humans, our Paleolithic ancestors had much shorter life expectancies—by some estimates, living only 33 years on average, with a mere 60% chance of even reaching age 15. ^[19] On the surface, this seems to challenge the logic of eating Paleo: why follow a diet that didn’t promote longevity?

While these numbers are technically true, they’re only a small piece of the puzzle. Unlike the chronic diet and lifestyle-related illnesses that plague humans today, mortality during the Paleolithic period was dominated by injury, infectious disease, high infant mortality, maternal death, and other threats unrelated to diet.

More specifically, about 75% of Paleolithic deaths were caused by infection (including diarrheal diseases that led to dehydration and starvation), an additional 15% of deaths were from violent injury, and about 1 out of every 100 mothers died in labor. ^[20] Average life expectancy was skewed significantly downwards as a result of these factors.

Thanks to modern medicine, sanitation, and other life-saving advancements, most of these environmental threats have been greatly reduced or eliminated as causes of death. Our greatest killers are now chronic in nature—diet and lifestyle-driven diseases such as cancer, heart disease, and diabetes. It’s in protecting against these diseases that the Paleo diet really shines.

What does the research say?

To date, hundreds of studies have been published on Paleo-style diets—including intervention trials, observational studies, and comparisons with other popular eating plans. The results of these studies show that Paleo eating:

• Improves cardiovascular risk factors more effectively than traditional “heart healthy” dietary recommendations—including greater reductions in LDL cholesterol, triglycerides, and blood pressure, and greater increases in HDL cholesterol ^[21] [22]
• Supports healthy weight loss, body fat loss, and a reduction in waist circumference (abdominal obesity) ^[23] [24]
• Is more effective at reducing body weight and markers of metabolic syndrome than standard dietary guidelines ^[25] [26]
• Significantly reduces fasting insulin, markers of insulin resistance, and markers of inflammation (C-reactive protein) ^[27]
• Significantly improves glucose control and lipid profiles among type 2 diabetics ^[28]
• Reduces levels of liver fat and risk of non-alcoholic fatty liver disease ^[29] [30]
• Brings clinical improvements (and in some cases complete resolution) of autoimmune thyroid disease ^[31]
• Increases gut microbiota diversity, a marker of gut health ^[32]
• Is associated with a lower risk of breast cancer in women (a 71% lower risk in premenopausal and an 83% lower risk in postmenopausal women) ^[33] [34]
• May help maintain glucose tolerance and iron stores during pregnancy ^[35]
• Reduces levels of inflammation and oxidative stress ^[36] [37]
• Is associated with lower risk of developing colorectal tumors ^[38]
• Effectively reduces symptoms of psoriasis ^[39]
• Improves mood, cognitive function, exercise capacity, and fatigue scores in people with multiple sclerosis ^[40] [41]
• Is more satiating per calorie than Mediterranean-style diets or diabetes diets ^[42] [43]
• Is associated with a reduction in cancer mortality, cardiovascular mortality, and all-cause mortality ^[44]

Importantly, research shows that perfect adherence isn’t necessary to obtain the benefits of this eating style; the closer you can eat to Paleo, the better! Studies using dietary adherence scores—in which people’s diets are assessed based on how closely they follow specific eating protocols—find that the more people’s diets resemble Paleo eating, the more their risk of cardiovascular disease, cancer death, and all-cause mortality drops. ^{[45] [46] [47]}

In other words, every step you take towards a Paleo-style diet should reap substantial benefits. If strict adherence seems too daunting, making whatever changes you can towards anti-inflammatory, nutrient-dense foods will pay off.

Is there more to Paleo than just food?

Although it’s typically referred to as a diet, the Paleo framework is ultimately about more than just food. It’s an overall approach to living in alignment with how our bodies are evolved to thrive, even within the context of our modern-day challenges and lifestyles.

Drawing lessons from the resilience of our ancestors, Paleo advocates also encourage lots of easy, low-level movement, functional strength training, time outdoors in the sunshine, an active approach to optimal sleep in line with our circadian rhythms, fostering good relationships, and stress management. Not only are these key features of ancestral living (most of which have only been lost relatively recently in human history); science confirms that these lifestyle elements, too, are strongly protective against chronic disease. ^{[48] [49] [50] [51] [52]}

At first, the Paleo diet might seem like a sharp pivot from the ways of eating and living that most of us are used to. But in essence, it’s a return to our roots. No matter where you’re starting from or how strictly you choose to follow Paleo-style principles, any movement closer to ancestral alignment is likely to positively impact your health and quality of life. You deserve to feel great!

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