Keto. Atkins. Mediterranean Sea. Vegan. Carnivore. Paleo. There are so many diets out there that claim to suit our natural design and be best for our well-being. Proponents of these diets debate what people 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 ills of modernity such as diabetes, heart disease and obesity. How can people who want to make informed decisions for their health and well-being figure out what to eat?
What is a good diet to follow?
When researching our book On the Origin of Being: Understanding the Science of Evolution to Improve Your Quality of Lifewe discovered that there is actually no single optimal diet that our ancestors followed, as some of the popular nutritional approaches mentioned above suggest. Hunter-gatherers ate vastly different proportions of macronutrients from a variety of plant and animal sources, depending on what they could get from their environment during that season.
Yet they managed to live relatively healthy lives in the rainforest, the tundra, the desert, the plains and everywhere in between. But instead of making you feel even more confused, we hope this knowledge will take some of the pressure off and provide you with some freedom. How? By giving you information and less rigid options than some popular diets. So, what was it about our ancestors’ diets that allowed them to have health and wellness?
Our ancestors consumed a wide range of macronutrient ratios, from 19% to 35% protein, 28% to 58% fat, and 22% to 44% carbohydrates.1 and they ate no specific ratio of plant to animal foods. While some researchers calculated that the average plant-to-animal ratio of our foraging ancestors was 65% plants and 35% animals,2.3 others calculated that the ratio was exactly the opposite.3 Scientists focusing on the diets of hunter-gatherers living in extreme climates also found striking differences. In the Arctic, only 5% of the Inuit diet came from plants and as much as 95% from animals. In the desert, 65% of the African Ju/’hoansi diet came from plants and 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 from modern diseases, regardless of whether the majority of their diet consisted of wild plants or wild animals.6.
What is a good eating plan?
But how could we eat such a range of foods and nutrients? First, we have used our intelligence and cultural adaptations, which have helped us acquire and process different foods in our environment in response to changing availability. We have actually adapted our behavior to solve nutritional problems. Second, we adapted to different macronutrient ratios by converting an available nutrient into a missing nutrient during metabolism. For example, our body can synthesize glucose from fats and proteins when we cannot eat enough carbohydrates, or convert glucose into fat when fat is lacking in our diet. The only nutrients that the human body cannot break down are nine amino acids and the polyunsaturated omega-3 and omega-6 fatty acids. These essential nutrients must be obtained from our diet. Nevertheless, it appears that our ancestors, whenever they could, tried to consume nutrients the way our bodies use them and not rely on conversion, because conversion takes energy and can potentially produce unwanted byproducts. In other words, a balanced diet is probably better for us.
Third, our ancestors may have adapted other genetic mechanisms called epigenetics and nutrigenetics. Some people have adapted to their specific diets through natural selection for thousands of years; or in other words, we have developed increased, decreased, or sustained expression of a gene, or developed a new gene that has helped us use certain nutrients better compared to others. For example, the Inuit are probably better adapted to consuming high-fat diets, and the Ju/’hoansi of the desert are better adapted to consuming high-carbohydrate diets. However, nutrigenetics is a very new field for which there is not yet much evidence. It would be a very interesting experiment for an Inuit and a Ju/’hoansi to switch places and see how they and their bodies cope with the huge change in diet.
How can we use this information to improve our diet? To live within our genetic design, we must first eliminate from our diet the foods that our ancestors did not eat, the foods that are now associated with the diseases of modernity. None of the foraging diets contained ultra-processed foods, such as white flour, refined sugars, refined vegetable oils, trans fatty acids or artificial colors, flavors or sweeteners. At no point in our evolution have humans been exposed to these foods, and so our bodies are not equipped to handle them. While the gurus of the diets mentioned above may argue about what people should eat, they all agree that we should not eat ultra-processed foods.
Second, regardless of where they lived geographically, our ancestors ate nutrient-dense and natural foods such as fruits, vegetables, naturally nourished meats, eggs, fish, shellfish, seeds, nuts, and healthy seed or nut oils. We ate these foods whole, meaning we never got any nutrients or fiber from their food. For example, we ate the skins, flesh and seeds of plants and the muscle flesh, organs and connective tissue of animals. Whole food provides more micronutrients, such as vitamins and minerals, and more different fats and proteins, such as collagen.
Next, we must consider the ultimate nutritional needs of our body. Believe it or not, all humans use nutrients in much the same way, and our underlying physiology and basal metabolic rate are very similar. We only need about 150 grams of carbohydrates per day for our brain and some other small tissues – about the equivalent of six pieces of fruit or whole wheat bread per day. An average person needs between 0.8 and 1.3 grams of protein per day per kilogram of weight, unless he is doing serious resistance training or high-intensity exercise, in which case he would need more, more than 1.6 grams per kilogram.7 Finally, our fat intake should only be 20% to 35% of our daily calories, lower if we are sedentary and higher if we get little exercise throughout the day. Most of us already store a lot of fat, so if we’re trying to get rid of fat stores, we need to limit fat in our diets, maintain protein, and eat whole carbohydrates to prevent sugars from also being stored as fat.
Unhealthy versus healthy eating
Finally, once we stop eating the wrong foods and start eating the right ones, we need to become aware of the signals our body is telling us – and then trust them. We are the product of billions of years of evolution, and evolution has given us the instincts to know what to eat. We should notice if within one family we seem to prefer one macronutrient over another or a particular type of food. What makes you feel good, and what makes you feel sick? When our body says, “Enough food!” we must honor this message. If we eat the foods we like and don’t force ourselves to eat the foods we don’t, we are more likely to stick to that diet. To help us stick to a new diet, many nutritionists advocate that people stick to the 80/20 rule: eat 80% of the foods that are in line with the diet and 20% of the foods that are not are.
As we rid ourselves of the foods we shouldn’t eat, find a diet of natural, unprocessed foods with the macronutrients and plant-animal ratios that keep you feeling healthy, know our nutritional physiology, and learn to listen to our body’s signals read. grant us that we are on the right path to better health and well-being. The bottom line is that we can trust that evolution has prepared our bodies to thrive when provided with the right kind of nutrition. We need to listen to our bodies, use our natural instincts and consider whether those who tell us otherwise are acting in their own best interests or ours.
References:
Connor, T. 2022. “Forget 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 relationships and estimates of macronutrient energy in the global diets of hunter-gatherers.” Ben 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, AN Schnorr, SL 2017. “Current views on hunter-gatherer diets and the evolution of the human diet.” Ben J Phys Anthropol 162(S63):84–109.
Milton, K. 2000. “Hunter-Gatherer Diets – Another Perspective.” Ben J Clin Nutr 71(3):665–667.
Wu, G. 2016. “Dietary protein intake and human health.” Food Function 7(3):1251–1265.