There Is No One Paleo Diet

Keto. Atkins. Mediterranean. Vegan. Carnivore. Paleo. So many diets out there claim to align with our natural design and be best for our wellbeing. Advocates of these diets argue over what humans should eat and which diet is right, making the topic of nutrition confusing. The rest of the modern world also bombards us with misleading, contradictory, and downright false information about our food. No wonder we struggle with the diseases of modernity like diabetes, heart disease, and obesity. How can people wanting to make informed decisions for their health and wellness figure out what to eat?

What is a good diet to follow?

In researching our book On the Origin of Being: Understanding the Science of Evolution to Enhance Your Quality of Life, we found that in reality, there is no single, optimal diet our ancestors followed as some of today’s trending dietary approaches listed above suggest. Hunter-gatherers ate wildly different ratios of macronutrients from a variety of plant and animal sources depending on what they could acquire from their environment in that season.

Yet, they managed to live relatively healthy lives in the rainforest, tundra, desert, plains, and everywhere in between. But rather than making you feel more confused, we hope that this knowledge eases the pressure a little and provides some freedom. How? By giving you information and less rigid options than some popular diets. So, what was it about the diets of our ancestors that allowed them to have health and wellbeing?

Our ancestors consumed wide ranges of macronutrients ratios, from 19% to 35% protein, 28% to 58% fat, and 22% to 44% carbs,¹ and they didn’t eat a specific ratio of plant versus animal foods. While some researchers calculated the average plant to animal ratio of our foraging ancestors to be 65% plants to 35% animals,^2,3 others calculated the ratio to be the exact opposite.³ Scientists focusing on the diets of hunter-gatherers living in extreme climates found striking differences, too. In the arctic, just 5% of the Inuit diet came from plants with a whopping 95% coming from animals. In the desert, 65% of the African Ju/’hoansi diet came from plants with only 35% from animals.⁴ The diets of the Hadza of Africa and the Plains Indians of North America contained fairly equal amounts of plants and animals.⁵ Our ancestors were largely free of diseases of modernity whether the majority of their diet came from wild plants or wild animals.^6.

What is a good eating plan?

But how were we able to eat such a range of foods and nutrients?  First, we used our intelligence and cultural adaptations, which helped us acquire and process different foods in our environment in response to changing availability. We basically adapted our behavior to solve dietary problems. Secondly, we adapted to different ratios of macronutrients by converting an available nutrient into a missing one during metabolism. For example, our bodies can synthesize glucose from fats and proteins if we aren’t able to eat enough carbs or turn glucose into fat if fat is missing in our diets. The only nutrients human bodies can’t make from another are nine of the amino acids and the omega-3 and omega-6 polyunsaturated fatty acids. These essential nutrients must be obtained from our diet. Nevertheless, it seems like whenever they could, our ancestors tried to consume nutrients in the ways that our body uses them and not rely on conversion, since conversion uses energy and can potentially produce undesired side products. In other words, balanced diets are probably better for us.

Third, our ancestors may have adapted other genetic mechanisms called epigenetics and nutrigenetics. Some people did adapt to their specific diets over thousands of years through natural selection; or in other words, we evolved an increased, decreased, or sustained expression of a gene, or evolved a new gene that helped us better utilize certain nutrients relative to others. For example, the Inuit are probably better adapted to consuming high fat diets, and the Ju/’hoansi of the desert better adapted for high carb diets. However, nutrigenetics is a very new field without a lot of evidence, yet. It would be a very interesting experiment for an Inuit and a Ju/’hoansi to trade places and see how they and their bodies cope with the vast change in diet.

How can we use this information to help us improve our nutrition? To live within our genetic design, we first must remove the foods in our diet that our ancestors did not eat, the ones now associated with the diseases of modernity. No foraging diet contained ultra processed foods, such as white flour, refined sugars, refined vegetable oils, trans fatty acids, or artificial colors, flavors, and sweeteners. Never at any point in our evolution were humans exposed to these foods, and so our bodies are not equipped to handle them. While gurus of the diets mentioned above may argue about what people should eat, they can all agree that we should not eat ultra processed foods.

Second, no matter where they lived geographically, our ancestors ate nutrient rich and natural foods such as fruits, vegetables, naturally fed meats, eggs, fish, shellfish, seeds, nuts, and healthful seed or nut oils. We ate these foods whole, meaning that we never stripped nutrients or fiber from their food. For example, we ate the skins, pulp, and seeds of plants and the muscle meat, organs, and connective tissue of animals. Whole foods provide more micronutrients, such as vitamins and minerals, and more of a variety of fats and proteins, like collagen.

Next, we must consider the ultimate nutritional needs of our bodies. Believe it or not, all humans use nutrients in about the same way, and our underlying physiology and basal metabolisms are very similar. We only need about 150 grams of carbs per day for our brains and some other minor tissues—about the equivalent of six pieces of fruit or whole grain bread per day. An average person needs between 0.8 and 1.3 grams of proteins per day per kilogram of weight, unless, they are doing serious resistance training or intense exercise, in which case they would need more, upwards of 1.6 grams per kilogram.⁷ Lastly, our fat intake should only be 20% to 35% of our daily calories, lower if we are sedentary and higher if we do low levels of exercise all day. Most of us already store plenty of fat, so if we are trying to lose fat stores, we should curtail the fat in our diet, maintain protein, and eat whole carbs to prevent sugars from being stored as fat, too

Unhealthy vs healthy food

Finally, once we stop eating the wrong foods and start eating the right ones, we must become aware of the signals our bodies are telling us—then trust them. We are the product of billions of years of evolution, and evolution gave us the instincts to know what to eat. We should notice if we seem to prefer one macronutrient over another or a certain type of food within one family. What makes you feel good, and what ones make you feel sick? When our bodies say, “Enough food!” we must honor this message.  If we eat foods we like and don’t force ourselves to eat the foods we don’t, we will be more likely to stay on that diet. Also, to help us stick to a new diet, many nutritionists advocate for people to aim for the 80/20 rule: eat 80% of foods that are in alignment with the diet and 20% of foods that are not.

If we get rid of the foods we shouldn’t eat, find a diet of natural, whole foods that has the macronutrient and plant vs. animal ratios that make you feel healthy, know our nutritional physiology, and learn to read the signals our bodies give us we will be on track for better health and wellness. The bottom line is to trust that evolution prepared our bodies to thrive when provided with the right type of nourishment. We must listen to our bodies, use our natural instincts, and think about whether those who tell us otherwise are acting in their own self-interest or ours.

References:

Connor, T. 2022. “Forget the Macronutrient Ratios. Here’s Why.” The Paleo Diet. Accessed April 7, 2022. thepaleodiet.com.

Lee, R.B. DeVore, I. Wenner-Gren Foundation. 1966. Man the Hunter. Chicago: Aldine Pub. Co.

Cordain, L. Miller, J.B. Eaton, S.B. Mann, N. Holt, S.H. Speth, J.D. 2000. “Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets.” Am J Clin Nutr 71 (3): 682-692.

Ulijaszek, S.J. Mann, N. Elton, S. 2012. “Evolving Human Nutrition: implications for public health.” New York: Cambridge University Press.

Crittenden, A.N. Schnorr, S.L. 2017. “Current views on hunter-gatherer nutrition and the evolution of the human diet.” Am J Phys Anthropol 162 (S63): 84-109.

Milton, K. 2000. “Hunter-gatherer diets—a different perspective.” Am J Clin Nutr 71 (3): 665-667.

Wu, G. 2016. “Dietary protein intake and human health.” Food Funct 7 (3): 1251-1265.