5 Reasons Why the Paleo Diet Works

food-tableConsuming a Paleo Diet is a very effective strategy for those who want to achieve a lean and healthy body. This statement isn’t only supported by thousands of anecdotal reports, but also by studies of hunter-gatherers, who are lean and healthy as long as they stick with their ancestral diet, and controlled trials which show that the Paleo Diet positively impacts metabolism, reduces waist circumference, and improves a wide range of other health markers (1, 2, 3). Just like other animals are lean and healthy when they eat the food they are well adapted to eat, humans also achieve robust health when our diet and lifestyle are in concordance with our biology. This is not to say that you have to avoid all food groups introduced after the agricultural revolution or never cheat on the diet, but as most paleo advocates will tell you, using the Paleo Diet as a starting place or template for designing your diet is a good idea if you want to achieve good health.

But why is the Paleo Diet so great?

This article of mine first appeared in Paleo Magazine, the first, and only print magazine dedicated to the Paleo lifestyle and ancestral health. You can subscribe to Paleo Magazine here!

Arguments about evolution, antinutrients, and macronutrient ratio aren’t always convincing

When the health benefits of eating a paleo-based diet are discussed, the evolutionary argument is often brought up. Although our environment has changed significantly since the paleolithic era, we still carry, to a large extent, the same set of human genes as our ancient ancestors, and it’s often stated that we haven’t fully adapted to foods that were introduced after the neolithic revolution, meaning that we should exclude most grains, dairy products, and modern foods from our diet in order to optimize gene expression. Antinutrients and “toxins” in these foods, such as lectins, phytic acid, and gluten, are often considered the primary offenders and sometimes blamed for triggering a leaky gut, low-grade chronic inflammation, and autoimmune disorders. However, while there’s definitely some truth to the notion that we haven’t fully adapted to eating neolithic foods, this theory has some flaws. Also, as so many paleo proponents know, a lot of people don’t grasp or believe in the whole concept of genetic adaptation, antinutrients, etc., and it can therefore be difficult to use this as a convincing argument when discussing the Paleo Diet.

Another health benefit associated with paleolithic diets is the relatively high protein content and low carbohydrate percentage these diets generally contain. Some traditional populations, such as the Kitavans on the Island of Kitava, maintain good healthy while eating high-carbohydrate, low protein ancestral diets, but these are the exceptions rather than the rule. Estimates from 229 hunter-gatherer societies show that most hunter-gatherer tribes eat/ate a diet that contained between 22-40% carbohydrate and 19-35% protein (5). Compared to the macronutrient distribution in “modern diets”, this is a low carbohydrate intake and a very high protein intake.

While it’s well established in the scientific literature that reducing your carbohydrate intake and increasing your protein intake can confer several health benefits, many laypeople – and even nutritionists – still think that “high-protein/low-carbohydrate” diets (compared to western standards) are either dangerous or inferior to the official dietary guidelines. It’s therefore difficult to use the macronutrient argument when discussing the Paleo Diet with a person who’s under the impression that everyone should eat a diet that contains 50-60% carbohydrate and 10-20% protein.

5 reasons why the Paleo Diet positively impacts health and body composition

So, even though arguments about genetic adaptation/evolution, antinutrients, and macronutrient intake are definitely worth mentioning when discussing the Paleo Diet, they aren’t always that convincing to a person who’s unaware or dismissive of the literature on ancestral diets. However, as we know, there are many other health benefits of eating a paleo-based diet, and in this article I’m going to highlight 5 essential concepts, some of which might be new even to those who’ve been reading up on diet and health.

I believe these 5 factors largely explain why the Paleo Diet is so great for weight loss. Because, as those who are familiar with the hormone leptin, the body fat “set point”, and homeostatic regulation of body fat know, weight loss isn’t just about telling someone to “eat less and move more”. What we want is to lose weight without deliberately restricting calories! And this is where the Paleo Diet really shines… Also, as these 5 concepts are based on hard facts, they can seem more convincing than some of the more “shaky” arguments people use to explain the benefits of a Paleolithic Diet.

For simplicity’s sake I’ll use the term “paleo foods” to refer to foods that are a part of paleolithic diets. As we know, there are now many different “versions” of the Paleo Diet out there, and there’s a lot of debate regarding which foods our Paleo ancestors actually ate (e.g., legumes were eaten by some hunter-gatherer bands). However, in this article I’ll focus on the original/”pure” paleo diet, which includes meat, seafood, vegetables, eggs, fruits, berries, roots, and nuts, and excludes grains, legumes, dairy, and all other foods that were primarily introduced in the human diet after the Agricultural Revolution.

This list provides a broad overview of the general characteristics of the food groups that are a part of Paleolithic Diets. I want to make it clear that there are some paleo foods that don’t qualify for all of the categories below (e.g., honey). However, these are definitely the exceptions rather than the rule.

1. Paleo foods have a low-moderate reward value

Why are we drawn towards certain foods again and again, while we aren’t that fond of others? If you are familiar with the research on the topic, you know that the reward value is a key to explaining this varying effect food has in our brain (5, 6). While highly processed foods like pastries, pizza, and doughnuts contain a potent combination of several rewarding ingredients such as fat, starch, salt, sugar, and/or glutamate, simple whole foods, such as vegetables, fish, and fruits, don’t contain this unnatural combination of nutrients. “Modern technology” has allowed us to create hyper-rewarding food which from an evolutionary point of view are completely new introductions in the human diet.

In an ancestral natural environment, these hard-wired mechanisms benefitted us in the sense that we seeked out safe and calorie-dense food. However, in the modern obesogenic environment, highly rewarding food is everywhere. Our ancient hard-wired mechanisms aren’t adapted to deal with these modern foods, and it’s therefore no surprise that so many people in the world today eat more calories than they need to sustain body weight.

This concept of reward doesn’t just apply to food, but also to many other aspects of our lives in the sense that we’ve been able to create drugs, social media platforms, etc. that many people essentially become addicted to. Many of the same mechanisms involved in drug addictions are also present in food addictions (7, 8).

Since the Paleolithic Diet consists of simple whole foods with a low-moderate reward value, this way of eating provides the types of inputs the human brain is best adapted to deal with. When you replace highly rewarding foods with meat, vegetables, and fruits you tend to unconsciously reduce your caloric intake.

2. Paleo foods have a high satiety index score

The satiety index is a measure of how full you feel after eating a specific type of food (per calorie of each food). Generally, the satiety value negatively correlates with palatability and calorie-density, meaning that baked goods, junk food, and foodstuff high in fat have a low SI score (9).

While many modern “paleo dieters” include plenty of olive oil, butter, cheese, and other foods with a very high fat density in their diet, it’s important to remember that these types of foods were not a part of paleolithic diets. This doesn’t necessarily mean that they are bad for you, but in comparison to meats, fruits, vegetables, and other paleo foods, these products score poorly in terms of satiety. Our ancient ancestors definitely ate the fattest part of the animal they could get their hands on, but they didn’t have access to oils, GHEE, and other products with a very high concentration of fat that are often included in modern versions of the Paleo Diet.

Foods twith a high SI score include steak, vegetables, fruits, and fish. Protein has an especially potent effect on satiety, and one of the primary reasons the Paleo Diet is so effective for weight management is because it usually contains a fairly high percentage of this macronutrient. Also, potatoes, beans, and lentils are satiating foods, which supports the notion that you shouldn’t necessarily exclude all legumes and starchy tubers from your diet, regardless of whether they are “paleo” or not.

3. Paleo foods aren’t excessively palatable

Palatability is often used interchangeable with food reward, but they aren’t exactly the same thing. While the reward system is responsible for reinforcing and motivating behaviors related to foods, food palatability simply refers to how much you enjoy a specific food. Generally, food with a high reward value (think doughnuts) is also the food you find most pleasurable, but it’s not always the case.

Food manufacturers know how to design products that are both extremely rewarding and palatable, and it’s therefore no surprise that so many people in the modern world seek out baked goods, chips, and other westernized foods again and again.

I think no one would disagree that there is a big difference between the palatability/reward of foods that are allowed on the Paleo Diet and refined foods that came into the human diet after the industrial revolution. However, these differences can also be seen when we compare some neolithic foods to foods that were available to our paleolithic ancestors.

4. Paleo foods have a high nutrient density

This is an area where even the most adamant anti-paleo people can’t argue against the benefits of the Paleolithic Diet. Sources of carbohydrate in the Paleoltihic Diet like vegetables, fruits, and berries are more nutrient-dense (on a calorie-by-calorie basis) than cereal grains (11). Of all the foods that are generally included in contemporary paleo diets, organ meats are especially rich in vitamins, minerals, and essential fatty acids.

Hunter-gatherers have a higher intake of most micronutrients (some exceptions, e.g., calcium) compared to individuals eating a low-fat, grain-based diet. While we clearly don’t have access to the exact same food as our ancient ancestors, it’s no doubt that a contemporary paleo diet scores extremely high in terms of nutrient density. This is especially true if you primarily choose organic and pasture-fed produce and include plenty of organ meats, fruits, and vegetables in your diet.

5. Paleo foods have a low-moderate energy density

Foods that were available to our prehistoric ancestors typically have a low energy density (average calories per weight (gram or ounce) of that food) compared to modern foods such as pastries, hamburgers, and pizza. This is also true when we compare fruits, vegetables, and berries to cereal grains; or most meats, fish, and eggs to full-fat dairy products.

Some of the most nutritious foods on the planet (e.g., fatty organ meats) have a high calorie density, indicating that foodstuff high in calories isn’t necessarily bad for you. However, the fact is that many of the most calorie-dense foods available today have a very low satiety index score and relatively poor micronutrient profile. This isn’t only true for the obvious offenders like junk food, but also for oils, GHEE, and other foods with a very high concentration of fat. Basically, they don’t fill us up as well as whole food.

Bottom line

I’ve always been a big believer in using the Paleo Diet as a starting place/template rather than a strict set of rules. However, the 5-item list above clearly shows us that the non-paleo foods many contemporary paleo dieters include in their diet, such as GHEE, butter, coconut oil, and high-fat yogurt, don’t score as well as meat, vegetables, fruits, seafood, and other foods allowed on the “pure” Stone Age Diet. This doesn’t necessarily mean that you should eliminate these foods from your diet (I eat them myself), but they shouldn’t make up a large portion of your caloric intake – at least if you’re trying to lose weight.

When we compare paleo foods to foods that were introduced in the human diet during the last several centuries, such as highly processed foods rich in vegetable oils, refined sugars, and/or refined grains, they come out ahead on every point. Also, if we compare paleo diet foods to “neolithic foods” like whole grains and full-fat dairy and then combine the results from all of the 5 categories, there is no doubt that a paleo-based diet is the best choice.

Picture: Creative Commons picture by Sebastiaan ter Burg. Some rights reserved.


  1. Excellent article; simple, natural foods are always best for humans.

    Don’t forget, also, that hunter gatherers also do not live in modern societies with our traffic jams, addictive technologies, television, computers and even books. They keep their active, simple lifestyles because that is how their society is designed. While we can eat nearly the same, our society is NOT geared to natural slimness.

    • Definitely, jean!

      Paleo man had to lead a healthy lifestyle simply because there was no other choice. It’s not as easy in a 21st century world where we can stay up long after dark if we want, have access to junk food in abundance, and can choose to be sedentary for our entire life. Choice: Double-edged sword.

  2. I also forgot to mention our overabundance of inexpensive food and cheap snacks overwhelm our choices, something hunter gatherers do not have to worry about. Always running after your meals guarantees a strong, slim body. Haha!

  3. the real problem is being able to make people understand that this is not just about choosing the right foods, but change their lifestyle, mentality, attitude … people do not want to get out of their comfort zone … our work as a nutritionist, now we can no longer rely on the only biochemical knowledge, epigenetic, nutritional food, but must also include the psychological knowledge, on working with certain subjects, quais all, who find it extremely difficult to make changes in their life more hectic and stressful.

    Erik greetings, from ITALY

  4. Would love to eat meat, however organic food is prohibitively expensive in the area I live. Any advise?
    Greetings from sunny Singapore 🙂

    • Hi Elena! Welcome to the blog!

      Couple of suggestions for you:
      – Buy in bulk when you come across high-quality meat or seafood that’s on sale, and then freeze it down for later use.
      – Organic eggs tend to be relatively cheap.
      – Remember that a Paleolithic Diet doesn’t have to be very high in animal products. Root vegetables, healthy fats (coconut oil, avocado, etc.), etc. are all good sources of calories and relatively inexpensive foods. You can also add in some legumes and high-fat dairy products.
      – Organ meats tend to be a lot cheaper than muscle meat.
      – Eat more wild-caught fish (e.g., mackerel), which tends to be a lot cheaper than grass-fed meats.
      – Although organic and/or grass-fed produce is great, you don’t have to completely shun conventionally produced meat and farmed fish.

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