paleo diet

What’s The Paleo Diet?- All you need to know to start a Paleo Diet

Paleo Diet, as well as a long list of many others such as Keto, The Zone, Mediterranean, SPMF,... have claimed to be the ultimate diet for health and longevity. We have a huge tendency to try find the ultimate and healthiest diet to live longer. But is there really one?

In this post we'll review the main characteristics of Paleo diet to later discuss the science behind and how you could implement it in your lifestyle. During this 5min read, you'll get an overview of what Paleo Diet is and the evidence behind.

Where Does Paleo Diet Come From?

Paleo Diet (although there's more than one) tries to simulate the diet that our ancestral Homo Sapiens followed during the Paleolithic, back a couple millenials ago in history. Paleo Diet SIMULATES (and not COPIES).

Foods, wether you like it or not, are 99% manipulated by humans nowadays, and what we know as an apple nowadays is not the same as an apple in the Paleolithic. But where does the idea of Paleo Diet come from?

Research and attention on Paleo Diet began during the 1970s, but it became widely popular with the release of the book The Paleo Diet: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat by Loren Cordain in 2002 (book). What the researchers were holding was that these diets, as they helped our ancesstors developed neural adaptation and evolve to what we are nowadays, they could potentially be benefitial for us.

When they started studying different ethnic groups around Africa and elsewhere, they found that these villages did not show a single case of cardiovascular events or anything alike. Surprisingly, that happened independently of the diet they were following. Wether it was high-carb, low-carb... the results were very similar (study)

The actual society is the main cause of many diseases leading to thousands of deaths each year (study)(study). Many researchers and scientists consider the evolutionary traits of human history as degrading in terms of overall health and nutritional status. What they defend is that nutrition back in the days could be more benefitial to us than the actual diets and agriculture stated the beginning of another age with deteriorated health status and fitness.

Characteristics of Paleo Diet

Paleo Diet is based on a certain food selection, and we cannot classify it based on its macronutrients content (as we do with low-carbs, high-protein,...). In a considerably short period of time (in 'evolutionary' terms), we have added a long list of new foods into our diets, either from the industrial  or the agricultural revolution. Along history, we have added ultraprocessed and industrial products, and others like dairy products or cereals.

Are various the potential effect attributed to Paleo Diet. Among them, we find:
- Low prevalence of cardiovascular events (study) (study)

- Improved body composition (study)

- Improve health parameters (study)

- Higher insulin sensitivity and glycemic control (study)(study)

Macronutrient Content of Paleo Diet

One thing we have clear is that Paleo Diet, different from others, is not strictly classified based on its macronutrient content and ratio. Because we have more than one Paleo diet depending on location, season,... we cannot talk about only one diet. In fact, we have a very good example here of the huge difference on their macro content.

Kitava Island: diet based on 70% carbohydrates (yam, sweet potatoes,...) (study)

Inuits: diet based on fatty fishes, seals and very low on carb (study)

Paleo diets have been highly associated to 'Low-carb diets' only because of the absence of the main carbohydrates being present in our diets nowadays (pasta, rice, bread, cereals). But that doesn't mean that there were no carbohydrates back in the Paleolithic. In fact, it is very possible to perform a 'High-carb Paleo Diet' including legumes, tubers, fruits and vegetables.

Paleo Diet carbohydrates

Food Selection of Paleo Diet

Paleo diet is based on: meat, fish, shellfish, fruits, vegetables, legume, tubers, eggs, and seeds.

However, these foods are just general ideas of what the Homo Sapiens ate back in the days, and there is a high variability between ethnic groups, time of the year, season, and location. The diet of an ethnic group living in the centre of Africa is not the same as the one followed by another group living in North of Canada.

Because of this important fact we cannot associate Paleo Diet with a low-carb. However, the carbohydrates included in this list show a very high satiety index (study) and  low glycemic index (study), so it could be considerably easier to perform a low-carb diet being constrained by the rules of a Paleo diet than an actual Western diet.

Paleo diet food list

Food Excluded from Paleo Diet

Another way to look at Paleo Diet is by the food we cannot eat, being this a better way to classify and perform the paleolithic diet. We cannot know exactly what our ancesstors ate on their daily basis, but we know for sure what they didn't eat.

They didn't eat ultraprocessed foods. They didn't eat dairy products nor cereals. They didn't eat flours, refined oils nor 'trans' fats. These foods were mainly introduced during the industrial revolution, thus not being available for our 'Paleo friends'. This means that their snack was not a Donut, their breakfast was not milk with cereals, and their nutrition was based on their hunting and recollecting.

Science Behind Paleo Diet

Paleo diet, different from other 'Miracle diets' -based on no science at all- show some confident scientific evidence behind. In the next paragraphs we'll try to explain and discuss the strongest evidence built behind it.

Cardiovascular Outcomes and Diabetes

Cardiovascular health is an emerging concern due to the high prevalence of cardiovacular events leading to severe health issues or even to death (study), getting 25% or all deaths taking place yearly.

Paleo Diet is effective at lowering cholesterol and improving the blood lipid profile (study), blood pressure and glucose tolerance, decreasing insulin secretion and increasing insulin sensitivity (study).

Not only cardiovascular diseases, but Paleo DIet may also other main causes of these diseases. When compared with a specific diet to treat Type 2 Diabetes, Paleo Diet was more effective at improving insulin sensitivity and glycemic control (study)(study)

This meta-analysis and systematic review concluded that Paleo Diet showed benefits over normal diets on cardiovascular outcomes.

Eight controlled trials were included in the systematic review, and the findings concluded that Paleo Diet could potentially benefit cardiovascular outcomes such as body weight, waist circumference, BMI and body fat percentage, among others. As you can see in the figure shown below, Paleo Diet is favoured on all diagrams.

Paleo Diet improves cardiovascular outcomes

Altough some of these benefits are enhanced by the application of a systemic calorie deficit due to the high satiety index of the diet, it seems like the distribution and election of foods has also a high importance, and benefits are also attributed to this fact. Other parameters such as C-reactive protein (inflammation marker) or total cholesterol and lipproteins were improved by Paleo Diet when compared to normal diets.

Body Composition

Body composition is of high interest in the fitness community. We train and 'diet' to get leaner, and some people may struggle with the process because of certain other facts slowering it.

Paleo diet is very satiating. If we look at the food list contained in Paleo Diet, we conclude that this diet is:

1) High in proteins. Protein is the most satiating macronutrient (study), above carbohydrates and fats. This means that 100g of lean meat will make you full, while you will need more of the isocaloric amount of nuts -around 15g- to start feeling full.

2) Paleo Diet is abundant in vegetables and low-caloric foods. This means that we'll have to eat way more to intake as many calories as with some other diets. For example, 100g of rice are equal to 450-500g of potato. Now I send you a question: what's going to make you more full?

These two facts could already help us achieving a lower caloric intake without struggling with hunger. In this study comparing Paleo Diets with a Mediterranian diet - considered a healthy and recommended diet - it was found that Paleo Diet was more satiating and calorie deficit was more likely to happen even when doing it Ad Libitum (based on feelings) (study).

Paleo Diet Improves the Gut Microbita

Human microbiome, and more in specific gut microbiota are considered by many as another internal organ connected to other systems in our organisms (source). It plays an important role in our health and immune system, and taking care of the health status of our microbes can help us achieving a higher quality of life.

Paleo diet is high in carbohydrates containing high amounts of fiber, such as fruits and vegetables. Fibers are non-degradable biomolecules being used by microorganisms to produce waste products. These will be used by us as energy substrate.

The introduction of new foods recently could have disturbed out gut microbiota. The Paleo Diet could help achieving a more consistent microbiota related to our natural evolutionary traits (study).


  • Paleo Diets are based on restricted foods similar to the nutritional habits back in the Paleolithic

  • There are multiple diets depending on the ethnic group, latitude, location, season,...

  • Paleo diets show improved cardiovascular markers and insulin sensitivity

  • In terms of body composition, Paleo diets could be a great tool to induce an easier calorie deficit

Potential Adverse Effects of Paleo DIet

Everything has its pros and cons, even the greatest thing you can think of. Now we have seen the main benefits attributed to Paleo Diet, but are there adverse effects that we should consider?

Loss of Apettite

Although this can be a huge benefit when trying to cut off calories to induce a calorie deficit, it is a problem when we are in our 'bulking' season and trying to build some muscle mass.

Paleo Diet is very satiating, usually being high in proteins and vegetables. If our daily caloric intake is around 3000 calories or above, eating such calories from this foods can get you into trouble. And trust me, you rather feel some hunger once in a while than being stuffed and full all the time.

paleo diets make you full

Paleo Diet may be Restrictive

This happens with any diets that restricts some sort of foods. We have a narrower spectrum of foods to choose from, making adherence to the diet harder and more boring.

Also, when deleting foods from our diets, we take the risk of showing some nutritional defficiencies and/or insufficiencies. From a start point, Paleo Diet is favoured to contain all sort of micronutrients to avoid any defficiencies, but let's go through the main ones:

+ Omega-3 and healthy fats: fatty fish, eggs, nuts, avocado.

+ Protein of quality: meats, white fish, eggs, insects.

+ Vitamin A: Liver, eggs, fatty fish, green veggies

+ Vitamin B: eggs, mushrooms, fruits, green vegetables, liver.

+ Vitamin C: orange, kiwi, blackcurrants, brocolli, peppers.

+ Vitamin D: eggs, fatty fish, sun exposure, liver.

+ Vitamin E: nuts and seeds

+ Vitamin K: green vegetables

+ Calcium: green vegetables, sardines.

+ Iodine: fish, shellfish.

+ Iron: meat, liver, beans, chickpeas, lentils

+ Magnesium: spinach, nuts

Paleo Diet could be able to cover all requirements to have a well-balanced diet. However, you have to be aware of this and try to combine different foods to get all the micronutrients and vitamins.

Change in Bowel Habits

When we perform sudden changes in our nutritional habits, our system and microbiota needs some time to adapt to the new diet to start functioning properly. This and the high content of fiber and other antinutrients present in foods such legumes can make you go to the bathroom more than usual (specially the first days).

Fruits and vegetables

Other Questions About Paleo Diet

Now we've gone through the main aspects of Paleo Diet. The food list, potential benefits and some facts to take into consideration. But I know that there are still some doubts flying around your head.

Is Paleo Diet for me?

All the choices you make in relation to your diet should point towards higher adherence. If you like eating clean and avoiding ultra-processed foods because you are against them, Paleo Diet is for you.

On the other side, if you crave sweets and donuts all the time and you can't live without them, maybe you'll have to do a longer transition before getting into Paleo Diet

Also, you should consider you caloric intake. If you are training and trying to build muscle you may have to intake huge amounts of 'paleo-foods' to reach your goal. In these cases, it may be better to leave the Paleo Diet for when you are cutting.

Is Paleo Diet better for Weight Loss?

It's not better or worse. It's simply another tool you can use to induce a calorie deficit. We need the calorie deficit to lose weight. Without it, we are not going anywhere no matter the diet we are following.

Calorie deficit can be achieved in many ways. You could lose weight only eating ice cream as far as you are in calorie deficit (the results won't be as good).

So we cannot say that Paleo Diet is better for weight loss when compared to other diets. However, due to the foods included, it could be easier to induce the calorie deficit than when following a diet based on ultraprocessed and high-calorie foods.

Does Paleo Diet improve my health?

So far, Paleo Diet could help improving cardiovascular outcomes and other diseases such as diabetes and metabolic syndrome. Paleo diets are based on natural foods, which make them, from a start point, way healthier and more benefitial for us than ultraprocessed foods.

But we still await more research on other fields to see how powerful this diet is and how far the idea of evolutionary nutrition can get.

Can I do a less restrictive Paleo Diet?

Of course you can. When we talk about nutrition, it's important to consider the long-term aspect. If we follow a restrictive diet for two weeks and go back to our normal 'shitty' diet, those two weeks were useless.

So if you enjoy once in a while some biscuits or cereals go for it. But base your diet on the foods contained in the 'Paleo List', otherwise you won't be doing a Paleo Diet anymore. Be flexible and follow the rule 80/20


In this post you learned what Paleo Diet is and what foods to include to follow it. Evolutionary nutrition is a very exciting field with much more to discover in the coming years. Agriculture and industrial revolution have marked a new age in history, and our body is still adapting to the new lifestyle.

Now you also know the main potential benefits of following a Paloe Diet. Here, where we can include with strong evidence the improvement of cardiovascular outcomes, lipid profile, insulin sensitivity and glycemic control. However, we don't know for sure wether some of these mentioned are consequences of the calorie deficit produced or Paleo Diet itself.

I hope you enjoyed the post and learned a lot from it. If you have any doubt, please leave it in the comments section.

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