Paleo Diet Overview
The name gives it away. The Paleo Diet is based on what prehistoric hunter-gatherer humans ate during the Paleolithic era, which began likely more than 2.5 million years ago, until the Pleistocene era, around 10,000 years ago. In his book The Paleo Diet, first published in 2002, Loren Cordain went with the 10,000 year mark, which also happens to coincide with the approximate time in history when humans did more than kill animals and forage, but began farming. 
So the diet then doesn’t just include prehistoric foods—meats from hunted land and sea mammals, foraged food like berries, nuts and seeds, and fruits from fruit-bearing vegetation—but includes foods that are cultivated, like modern-era vegetables found in the Almond-Lime Kale Salad recipe. By way of example, the aforementioned almond originally was wild and contained a substance that converts to cyanide; wild almonds were poison. Early farmers found a mutation and produced the almonds we eat today—ones that won’t kill us.   
In any event, perhaps the diet should be called the Pleistocene diet. Doesn’t have the same ring to it, though does it? Let’s take a closer look to see what Cordain came up with and why The Paleo Diet became so popular.
The Paleo Diet Claims
Cordain, a health and science professor emeritus at Colorado State University, spent two decades researching “the evolutionary and anthropological” human diet and is described on The Paleo Diet website as “the world’s leading expert on Paleolithic diets.”  His books include The Paleo Diet and The Paleo Diet Cookbook.
To start, and just to be clear, quite a bit of the content on The Paleo Diet website is sponsored, so while I will be sourcing the site, it’s possible that some content may have been curated by The Paleo Diet website and incorporated. But, straight from the Premise section of the website, The Paleo Diet is described as being based on “modern foods that mimic foods of pre-agricultural, hunter-gatherer ancestors.”  
(Jumping in here for a moment; the diet does include post-agricultural foods which we’ll see shortly.)
Cordain says the 7 “fundamental characteristics of hunter-gatherer diets will help to optimize your health, minimize your risk of chronic disease, and lose weight.” 
Those fundamentals are:
- a high protein intake of twice the average of a modern diet, so up to 35 percent of the hunter-gatherer diets was animal product and hence comprise the “staple foods” of Paleo diets;
- non-starchy low-glycemic fruits and vegetables (digested and absorbed slowly; won’t spike blood sugar levels) are the primary carb source, providing up to 45 percent of your daily calories;
- high fiber intake is key, but in The Paleo Diet you’re not permitted to get that fiber from whole grains; rather, it must come from the above non-starchy fruits and vegetables;
- no trans fats—that’s good; they will kill us—rather, healthy monounsaturated and Omega-3 fats “that were the mainstays of Stone Age diets;”
- more potassium and less sodium (also sounds good). 
Unprocessed, fresh foods naturally contain 5 to 10 times more potassium than sodium, and Stone Age bodies were adapted to this ratio. Potassium is necessary for the heart, kidneys, and other organs to work properly. Low potassium is associated with high blood pressure, heart disease, and stroke – the same problems linked to excessive dietary sodium. Today, the average American consumes about twice as much sodium as potassium.  (emphasis added)
But here’s where I get confused. Cordain says:
After digestion, all foods present either a net acid or alkaline load to the kidneys. Acid producers are meats, fish, grains, legumes, cheese, and salt. Alkaline-yielding foods are fruits and veggies. A lifetime of excessive dietary acid may promote bone and muscle loss, high blood pressure, and increased risk for kidney stones, and may aggravate asthma and exercise-induced asthma.
Okay then, I am wondering, why all the meat in this diet?
And finally, we need more vitamins, minerals, and antioxidants. Cordain says whole grains are “not a good substitute for grass produced or free ranging meats, fruits, and veggies, as they contain no vitamin C, vitamin A, or vitamin B12. Many of the minerals and some of the B vitamins whole grains do contain are not well absorbed by the body.” 
So that’s the idea.
On The Paleo Diet you eat lots of protein, get your carbs from vegetables and fruits, and your healthy fats from seeds and nuts (except peanuts.) And when you eat like prehistoric humans, Cordain claims, not only will you be healthier, but you will lose weight by cutting carbs when you stop eating all grains. You are also prohibited from eating legumes—largely because they are farmed, apparently. You cannot eat dairy. You cannot eat refined or processed foods (which makes sense) and no salt (okay with that, too).
The Paleo Diet claims it’s the “world’s healthiest,” because, Cordain says, it’s the diet we are genetically adapted to eat. Some science calls that bunk, though, since we have evolved in the last couple of million years.
On The Paleo Diet, the site claims, you may reduce your risk of heart disease, type 2 diabetes, and most chronic degenerative diseases; lose weight; improve athletic performance; slow (or reverse) the progression of an autoimmune disease; clear your skin; sleep better and have better sex; and overall, have improved mental clarity and a longer, healthier and more active life. 
That’s what it claims. Wow.
So what does a day of eating on The Paleo Diet look like?
From the website, this is a suggested menu:
- For breakfast, have Omega-3, free range scrambled eggs cooked in olive oil and topped with parsley, fresh fruit and herbal tea;
- For a mid-morning snack, slices of beef (grass-fed, organic and lean; so not from your discount grocer) and fruit;
- Lunch is a Caesar salad with chicken and lemon and olive oil dressing and herbal tea;
- Your afternoon snack is apple slices and raw walnuts;
- And dinner is sliced tomatoes and avocado, turkey, lots of veggies (broccoli, carrots and artichokes), and a bowlful of blueberries, raisins and almonds for dessert—all washed down with mineral water or, a glass of white wine.
Whoa! Wait. Yes, as I have already suggested, some (a lot) of what is on this diet certainly was not only not forageable during the Paleolithic era but didn’t even exist, like wine.
Here’s why you can have it: Cordain’s “15/85” rule:
…built into The Paleo Diet is the 85:15 rule which allows people to consume 3 open meals per week, so that they don’t have to forgo favorite foods forever. A little bit of cheating is a good thing if in the long run it behaviorally helps people to stick to the diet in the long run. If you want to go out with friends on a Friday night and have pizza and beer, then do so and enjoy, however don’t make this a regular habit. 
I’ve read people are curious if there are supplements or special foods to buy from The Paleo Diet website. Yes, there are ‘products’ you may purchase on the website store  but are largely Cordain’s own books and papers. That said, The Paleo Diet does permit—and one can only assume receives a cut of sales—Paleo Diet-approved foods and products by other companies, like ButcherBox.com.  The Paleo Diet food and beverage store philosophy is simply this:
For some people, buying Paleo-labeled products can help to stay compliant with the diet. Consequently, here at ThePaleoDiet.com we want to help you decide if a product is something you should to add to your grocery list. 
The Paleo Diet Meal Plan
What does a Paleo Diet meal plan include? You eat meat (and animal products), fish, vegetables, fruits, nuts, seeds and “healthful” oils like olive and walnut, for example. (I’m going to bring the subject of oils up again in my Bottom Line.) Oh, and eggs. 
About eggs: Stone Age humans likely found and ate wild bird eggs, but it wasn’t until 6000 or 7000 BC that chickens were domesticated and eggs “farmed”  rather than being found in the wild. Here’s an example of this diet being not quite all Paleo and rather a touch Pleistocene.
And about fruits and vegetables: fruits were likely a more common part of the Stone Age diet, as were starches (like fruits) in the Neanderthal diet. In fact, some 800,000 years ago folks were enjoying wild pears and even plums. 
But vegetables? That’s another story. Many Paleo recipes include vegetables like broccoli, Brussels sprouts, cabbage, cauliflower, and kale. None of these existed in the way we know them now, but their ancient ancestor the brassica species was purposely agriculturally evolved into scores of leafy greens and cabbage-family vegetables of the modern world. So in theory, I suppose, if prehistoric humans located this wild species and fed upon it, it certainly has the lineage—though not the variety—of so many vegetables found throughout the world, since farming and agriculture began in the Pleistocene era. Just saying. 
The Mayo Clinic has a concern about the ingredients in the diet; or lack of ingredients might be a more accurate way of expressing its sentiment.
“The primary difference between the paleo diet and other healthy diets is the absence of whole grains and legumes, which are considered good sources of fiber, vitamins and other nutrients. Also absent from the diet are dairy products, which are good sources of protein and calcium.” 
The Science Behind the Paleo Diet
On the website, there is a list of almost 100 scientific articles that purport to back up the premise behind The Paleo Diet. I scoured through it. You should too if this diet is of interest to you. Much of the science cited is related indirectly and not specifically to the actual Paleo Diet, but you catch the drift. 
I don’t use research posted on a diet’s website as proof; I do my own searches.
New York University’s (NYU) Marion Nestle, a molecular biologist, wrote a fair—albeit critical—paper called “Paleolithic Diets: a Skeptical View,” in 2015 where she challenges Cordain’s assumptions and conclusions that support his books and diet with study (based on a handful of ‘modern’ groups of hunter gatherers including Arctic and African tribes. Nestle says,
…knowledge of the relative proportions of animal and plant foods in the diets of early humans is circumstantial, incomplete, and debatable and there are insufficient data to identify the composition of a genetically determined optimal diet. The evidence related to Paleolithic diets is best interpreted as supporting the idea that diets based largely on plant foods promote health and longevity, at least under conditions of food abundance and physical activity.” 
Nestle is the Paulette Goddard Professor of Nutrition, Food Studies, and Public Health at NYU.
Bill Nye the Science Guy has a popular Netflix original series, Bill Nye Saves the World, where in a recent episode he dismissed fad diets; in particular, The Paleo Diet. “This meat, fruit and nuts thing,” he called it. “A lot of these fad diets are chasing trends, but not health,” Nye says. Vegans were thrilled. Paleo aficionados, not so much. 
Perhaps Nye is too casual, kitschy; too-TV.
The Mayo Clinic says researchers disagree about The Paleo Diet’s premise, arguing the diet “may oversimplify the story of how humans adapted to changes in diet.” Mayo says one would need to look at the variations in diet from one part of the globe to the other—the climate, what grew, and what roamed. And, the Mayo Clinic says,
Archaeological research has demonstrated that early human diets may have included wild grains as much as 30,000 years ago—well before the introduction of farming. … Genetic research has shown that notable evolutionary changes continued after the Paleolithic era, including diet-related changes, such as an increase in the number of genes related to the breakdown of dietary starches. 
An article published in 2013 on Scientific American magazine’s website makes no bones about its disdain for the science of Cordain’s Paleo Diet, calling it “half-baked.”
We are not biologically identical to our Paleolithic predecessors, nor do we have access to the foods they ate. And deducing dietary guidelines from modern foraging societies is difficult because they vary so much by geography, season and opportunity. 
Word on the Street About The Paleo Diet
On Amazon, there are several of Cordain’s paleo diet-related books. I decided to go with the original, though this is a 2010 edition with what I assume are some revisions. With more than 800 reviews and an average of 4.3 stars, it appears readers, and dieters, are fans. Big fans. Nearly 70 percent of the reviews were 4-star or better. Very impressive results. 
“Earthian” (Jul 2017, 5 stars) says it’s an “excellent primer on returning your body to health.”
Great book laced with studies and facts that you won’t see in many books these days. Cordain lays out his thesis telling us that our Paleo ancestors were wired for health and for us to do likewise requires a shift backward and away from processed foods laced with poisons that our bodies cannot digest without leading to significant diminishment in our health. I have been following his advice and can tell you I have never felt better in my life and I have only been on this diet a short time. If you want change, and a return to the original way the human body functions exquisitely follow Cordain’s ideas. Put succinctly: they work! 
“Sporty” (Mar 2017, 5 stars) says simply, “Not just a diet; it’s about nutrition.”
This is the most common sense nutrition plan out there. Explains what our bodies are designed to eat. I stumbled into this book in researching a couple nutritional truths I learned by experience, and now I have the whole picture. 
My favorite review is this one from “Rob J” (Mar 2017, 5 stars), who admitted, “I’m still fat but this is a good book.” 
An interesting review from “G. Jones” (Jul 2017, 5 stars) reads more like a Paleo-as-medicine review than a diet one. Also, “G. Jones” has quite the political agenda, but all that said, The Paleo Diet worked for Jones:
Followed this diet, lost 15 pound, back to my high school weight. My weekly migraines stopped. My 20 year back pain from herniated disk, tennis elbow and old motorcycle accident knee injury all stopped hurting. All I have to do is eat a pizza or sandwich if I want the pain back. Also I generally feel better and have more energy. It is not easy because pizza and chips and salsa and deli sandwiches all taste great, but it is worth it and not that hard to make the food amazing choices.
Oh and I have three kids. One had ADD, another migraines and two bad acne, on this diet all cleared up.
To get political for just a minute. If you read this and watch movies like ‘Corn King’, and ‘In Defense of Food’ you will find that corn is a major source of the heath issues in our country, yet the government subsidizes the growing of corn, leading to 30 percent of Americans being diabetic or pre-diabetic causing healthcare costs to skyrocket and now they what to fix health care; how about stop paying farmers to grow poison and direct them toward growing Paleo-friendly foods.
Try this for 6 months hard-core and notice your ailments fade. Like I said, if I want a headache, I just need to eat a pizza or drink a beer.
Oh, one other thing, don’t (fall) for the masses of “gluten free” junk food like cookies, etc. These are just made of corn instead of wheat and are not paleo. Sorry but all cookies are junk food. Eat real food, you will be amazed.  (paragraph breaks added for clarity)
But “Anna” (Jul 2015, 1 star) called it bunk; “misleading and scientifically incorrect.” 
Like Anna’s, there were a number of very critical reviews about Cordain’s premise. Some were pretty benign and others positively brutal—like the review by “Robert M. Yanetta” (Sep 2013, 1 star):
“There’s a lot to talk about here, but I’ll be brief and give you some direction as to where the author want you to think. It talks about protein A lot but to claim our ancestors didn’t eat any dairy or nuts in the past is just lame. Sure, some things like eggs and nuts are not as high as turkey and venison in protein, but to say you can’t eat what was available back then is utter bull. I got halfway through this book and put it down, swearing not to finish it. I don’t know what the author’s influences are, but they are wrong, nuts and berries existed 10,000 years ago as well as fresh eggs and pork. This newly revised version of the diet looks to be heavily influenced by an outside source (perhaps [Cordain] found a sponsor with an agenda?) and makes no common sense. There are many dietary recommendations that conflict with each other day by day. One day this could be bad, but the next, it’s healthy for you. Stay away from this book as I’ve found the secret to dieting: put the effing fork down. There, I’m shedding weight already.” 
Is The Paleo Diet Worth a Try?
Risky (mid to high risk). Many researchers have called “foul” on The Paleo Diet. Although Cordain has plenty of his own science (and his curriculum vitae is impressive) to back up his premise. 
And The Paleo Diet does get some stuff right; I agree about the no-processed foods rule. That makes sense.
But this diet is the antithesis of the heart-healthy Mediterranean Diet, for example, which limits meats and emphasizes vegetables, whole grains, legumes, healthy oils and fats. The amount of meat consumed in The Paleo Diet is a bridge too far for me and cutting out incredibly healthy whole grains—like barley, quinoa, buckwheat, and the newly discovered by me and now favorite freekha—leaves a gaping hole in the nutrition. Plus no legumes! What? No black beans? Black beans are a great and powerful food, providing anthocyanin. Puleeze. And no lentils? They are a cancer-fighting food. Wait! No garbanzo beans? They balance your sugar levels. Come on.
One other note: I’d bet the ranch that Paleolithic humans did not have tools to cold-press olive oil or create other beautiful oils like walnut, flaxseed and coconut. I know, I know; some say don’t take it literally. But that’s exactly what Cordain wants us to do: take it literally.
Plus, The Paleo Diet is not cheap: Omega-3, free-range eggs are four times the cost or regular eggs, organic fresh fruit is pricey, and certainly grass-fed meats are more expensive. That said, if I fed my family beef (I don’t), I suppose grass-fed would be a better choice than plastic-wrapped plain old USDA-inspected.
Finally, if you are still on the fence about The Paleo Diet, reading the Scientific American article I referenced may help you decide. I’d already made up my mind, but there’s a certain clarity that comes after reading what science has to say.
I love science. But this diet? Not so much.
Top 5 Diets in 2018*
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*Individual results will vary.
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