What Is the Paleo Diet?

Paleo Diet

Story at-a-glance

  • The Paleo Diet focuses on eating like a “caveman” from the Paleolithic period: lean meat, seafood, fresh fruit, and non-starchy vegetables are its foundation
  • Cutting back on processed foods, including sugars and grains, is a Paleo Diet element that can benefit most people
  • The Paleo Diet may be too high in protein, and too low in carbs, for some people
  • My nutrition plan allows whole, raw dairy products and also includes fermented vegetables for gut health and a focus on replacing excess grains and proteins with healthful sources of fat


This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.

By Dr. Mercola

The Paleo Diet is one of the hottest diet trends around. With celebrity followers and even high-end restaurants taking notice of Paleo principles, some might even say Paleo has gone mainstream. As the diet has grown in popularity, so too have its vocal supporters… and critics.

There's now a growing debate over whether the Paleo Diet is truly healthful or not, so I want to take a moment and shed some light on this method of eating. I thought I should comment, as many in the media describe my recommendations as Paleo, which they aren't.

The Paleo Diet: What Is It?

While we may consider ourselves to be at the pinnacle of human development, our modern food manufacturing processes have not created a race of super-humans in possession of greater health and longevity. Quite the contrary... Humans today suffer more chronic and debilitating diseases than ever before. And there can be little doubt that our food choices play a major role in this development.

During the Paleolithic period, many thousands of years ago, people ate primarily vegetables, fruit, nuts, roots, and meat, which varied depending on season and availability.

Based upon scientific research examining the types and quantities of foods our hunter-gatherer ancestors ate, the foundation of "The Paleo Diet" is lean meat, including ostrich and bison as well as organ meats, seafood, fresh fruit, and non-starchy vegetables -- a far cry from the standard American diet.

Today, these staples have been largely replaced with refined sugar, high fructose corn syrup, cereal, bread, potatoes, and pasteurized milk products. Most Americans eat a much narrower selection of fruits, vegetables, roots, and nuts, and in lesser quantities than our "cavemen" ancestors.

"Normalizing" your system is the true strength of the so-called caveman diet. By eating foods that are concordant with your genetic ancestry, you can avoid many of the diseases associated with our modern diet, and which far too many still believe is predetermined by "bad genes." As Dr. Loren Cordain, author of The Paleo Diet and one of the world's leading experts on Paleolithic nutrition, stated:

"The nutritional qualities of modern processed foods and foods introduced during the Neolithic period are discordant with our ancient and conservative genome. This genetic discordance ultimately manifests itself as various chronic illnesses, which have been dubbed "diseases of civilization."

"By severely reducing or eliminating these foods and replacing them with a more healthful cuisine, possessing nutrient qualities more in line with the foods our ancestors consumed, it is possible to improve health and reduce the risk of chronic disease."

What Do the Critics Say About Paleo Principles?

It's hard to argue against replacing modern processed foods with whole foods from nature. But critics argue that the Paleo Diet may be too restrictive, putting strict followers at risk of nutritional deficiencies and proving to be unrealistic to follow for the average American.

In its 2014 rankings of the "Best Diets Overall," U.S. News & World Report rated the Paleo Diet dead last at #31 (tied for last place with the relatively unheard of Dukan diet -- even Slim Fast placed #13),1 noting:

"Experts took issue with the diet on every measure. Regardless of the goal—weight loss, heart health, or finding a diet that's easy to follow—most experts concluded that it would be better for dieters to look elsewhere."

The criticism largely surrounds the diet's restriction of grains and dairy, the former of which is one of the key reasons why Paleo eating is far healthier than the average American diet. Another oft-cited criticism of the Paleo Diet is minimal research supporting its benefits, although there are clinical trials (albeit small ones) supporting its use.

For instance, a study by researchers from the University of California had out-of-shape volunteers eat a Paleo Diet for two weeks. In that time, their blood pressure levels decreased, as did their levels of cholesterol, by an average of 30 points, which the researchers compared to "the type of drop you get by taking statins for six months." Their levels of triglycerides also improved.2

Finally, U.S. News' ranking suggests that the Paleo Diet is unrealistic because the panelists didn't believe it was possible to find the appropriate foods in the modern era. Nothing could be further from the truth, because food selection today is no longer dictated by your environment as it was so long ago, but rather by your choices at the supermarket or, better, the farmer's market.

While you wouldn't be able to find many of the wild varieties of plant foods eaten by cavemen even if you wanted to, because modern agriculture has largely taken over the food supply and tweaked and shrunk it to where only a few varieties of wheat, corn, and other plant foods are left, you can certainly mold your diet around the principles of Paleo eating rather simply just by tweaking the way you shop.

The Paleo Diet May Be a Problem for Some People

While I do believe that the Paleo Diet can be a healthful way of eating, especially compared to the Standard American Diet, I also believe it has certain weaknesses or flaws that could be improved upon.

The primary one is that I believe it has far too much protein for most people. Protein is freely substituted for carbs as being a healthy choice. I believe it is the rare person who really needs more than one-half gram of protein per pound of lean body mass. Those that are aggressively exercising and competing or pregnant women should have about 25% more, but most people rarely need more than 40-70 grams of protein a day.

To determine your lean body mass, find out your percent body fat and subtract from 100. So if you are 20% body fat you would have 80% lean body mass. Just multiply that by your current weight to get lean body mass. For most people, this means restricting protein intake from 35 to 75 grams a day. As mentioned, pregnant women and those working out extensively need about 25% more protein though.

Also, some believe that the Paleo Diet is too low-carb for some people. Generally speaking, if you're on a high-carb diet and suddenly reduce your carb intake, your blood cholesterol profile will improve. Typically, your triglyceride levels will be sharply reduced.

However, if your carb intake is below 25 percent (the Paleo Diet is about 23 percent carbs), your body will have to adapt to a scarcity of glucose, which can cause hormonal changes that may negatively impact your blood lipids. According to Dr. Paul Jaminet, a trained astrophysicist and author of the book Perfect Health Diet, you may be able to tolerate an extremely low-carb diet if your health is really good, because your body can manufacture some glucose from protein.

Others may not fare as well. He explained:

"The biggest problem is it's not a robust diet. If you get infections (which will raise your body's glucose needs), then you can really get into trouble on a zero carb diet. In general, it's a stressful thing for your body."

While some experts, such as Dr. Ron Rosedale, believe you can't have too little glucose because it's always going to cause some adverse metabolic consequence, Dr. Jaminet, on the other hand, believes that once you get below a certain threshold of glucose in your diet, you can start experiencing certain health challenges.

I have revised my position on using low carb long term and now believe that the low carb, low to moderate protein, high healthy fat diet is appropriate for most who are insulin or leptin resistant. Once that resistance resolves, then it likely becomes counterproductive to maintain a low-carb approach. Once your weight, blood pressure, sugar, and cholesterol normalize, you can increase your carbs.

Personally, I now consume several pieces of fruit a day and have two dozen fruit trees in my yard, but my body weight, fat and insulin resistance are all optimized.

Does the Paleo Diet Contain Too Much Protein and Not Enough Fat?

When you are treating insulin/leptin resistance, I believe most would benefit by decreasing carb consumption, and replacing them with healthy fats. Replacing carbs with too much protein can actually cause health challenges similar to eating too many grain carbs and sugars. The Paleo Diet is about 38 percent protein and 39 percent fat, which may actually be too much protein and not enough fat for optimal health.

When you consume protein in levels higher than recommended above, you tend to activate the mTOR (mammalian target of rapamycin) pathway, which can help you get large muscles but can also increase your risk of cancer. This pathway is ancient but relatively recently appreciated and has only been known for less than 20 years.

Odds are very high your doctor was never taught this in medical school and isn't even aware of it. Many new cancer drugs are actually being targeted to use this pathway. Drugs using this pathway have also been given to animals to radically extend their lifespan. But you don't have to use drugs to get this pathway to work for you.

As mentioned, when you reduce protein, you need to replace it with other calories, so the key is to replace the lost calories with high-quality fats such as avocados, butter, coconut oil, nuts, and eggs. Your healthiest option is to ensure your carbs come primarily from fresh, organic vegetables, eat limited amounts of high-quality protein, and eat primarily a high-fat diet.

Depending on the type of carbs (high fiber or not), most people need anywhere between 50-75 percent fat in their diet and sometimes even higher for optimal health.

Key Differences Between My Nutrition Plan and the Paleo Diet

My nutrition plan has many similarities with the Paleo Diet, namely the restriction of sugars and grains, increases in fresh vegetables and a focus on finding high-quality, toxin-free food sources. However, there are some key differences that I want to highlight, as I believe these factors can make a significant difference in your health. My nutrition plan contains the following dietary advice, which the Paleo Diet is lacking:

Less protein, higher healthy fat — In general, it would be unusual for most adults to need more than 100 grams of protein and most likely need close to half that amount. When you reduce protein, you need to replace it with other calories, specifically high-quality fats such as avocados, butter, coconut oil, olives, olive oil, nuts, and eggs.

Dairy is allowed — Dairy, particularly full-fat raw dairy, is allowed in my nutrition plan. I personally do not drink much milk nor think it is necessary to drink milk, but raw dairy does have some worthwhile nutritional components, as do other whole raw dairy products, like raw-milk cheese.

Seafood should be eaten with caution — The Paleo Diet includes fish and other seafood as a regular meal. However, it is difficult to find seafood that is free from toxin buildup as a result of pollution. For this reason, I recommend only safe sources of seafood, such as wild Alaskan salmon, sardines, and anchovies, as well as a high-quality, animal-based omega-3 fat supplement (krill oil) to make up for lacking seafood in your diet.

Fermented vegetables — One of the best ways to protect your health is by keeping your gut flora healthy by eating naturally fermented foods. Fermented vegetables are a key component of this and are highly recommended in my nutrition plan. One-quarter to one-half cup of fermented veggies with each meal is ideal, but you may need to work up to this amount gradually.

Intermittent fasting — The Paleo Diet is supportive of intermittent fasting, although it does not specifically highlight it. However, intermittent fasting or "scheduled eating" is one of the most powerful interventions I know of to shed excess weight and reduce your risk of chronic diseases like diabetes and heart disease.

There are many different variations of intermittent fasting, but if you are like 85 percent of the population and have insulin resistance, my personal recommendation is to fast every day by simply scheduling your eating into a narrower window of time.

In Doubt About What to Eat? Read My Nutrition Plan

Dietary advice can be a bit of a moving target, as everyone has unique nutritional needs and what's "best" is a highly controversial topic in the media. To be most beneficial, dietary advice needs to be regularly revised based on new research and increases in wisdom from personal explorations of applying this research.

There are some dietary basics that are foundational, which I believe will likely never really change, at least in our lifetimes, such as avoiding processed foods and limiting sugar intake as much as possible. But virtually everything else is evolution in process. The challenge is to keep up-to-date with it all and have a process that allows you to integrate this information using an easily digestible format.

That is one of the primary reasons behind the compilation of my nutrition plan. In the '90s I rejected the idea of writing a book, as by the time it was printed it would be out of date. That is one of the reasons I chose to focus my efforts on the Internet. I strongly recommend reviewing my nutrition plan whenever your schedule allows.

It is a very detailed and comprehensive program — it's basically an entire book in multimedia format. The plan is divided into three stages: beginner, intermediate, and advanced. If you realize you're already doing all the things included in the beginner's phase, then it may be time to move on to the next phase.

If you're new to the site, I encourage you to go through it from the beginning, as it is one of the most powerful tools to truly allow you and your family to take control of your health. If you're a Paleo Diet fan, you may be able to jump in at the intermediate or advanced level, taking your health to an even higher level than you had before.


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