Weight Maven

Last week, some of “the” names in the academic paleosphere — Pedro Carrera-Bastos, Maelan Fontes-Villalba, James H O’Keefe, Staffan Lindeberg, and Loren Cordain — posted a comprehensive review article titled “The western diet and lifestyle and diseases of civilization” (abstract, full PDF).

It made quite the buzz in paleo social media (over 28K downloads) and Stephan Guyenet called it “the best review of the underlying causes of the ‘diseases of civilization’ that I’ve encountered.”

It’s a readable paper, even for us non-academics. But for those whose eyes glaze over at any kind of white paper, I’ve taken the liberty of highlighting some key passages below.

Insufficient time to adapt

The major premise of ancestral health is that there hasn’t been enough time for us to have adapted to the “fundamental changes in diet and lifestyle” — especially highly processed industrial foods.

[M]ost of the human genome comprises genes selected during the Paleolithic Era in Africa, a period that lasted from about 2.5 million years ago to 11,000 years ago. Indeed, anthropological and genetic studies suggest that all human beings living in Europe, Asia, Oceania, and the Americas share a common African Homo sapiens ancestor. This concept is corroborated by data showing that there is less genetic diversity throughout the world’s non-African population than there is within Africa itself.

Importantly, 11,000 years represent approximately 366 human generations, which comprise only 0.5% of the history of the genus Homo. Indeed, the Industrial Revolution and the Modern Age, which mark the beginning of the western lifestyle, represent only seven and four human generations, respectively and were marked by rapid, radical, and still ongoing changes in lifestyle and diet, coupled with improved public health measures that greatly reduced mortality in the pre-reproductive years (and hence largely eliminated impaired reproductive fitness as a selection pressure). As such, it is highly unlikely that genetic adaptations that allow us to thrive on a western diet and lifestyle have occurred.

Longevity then and now

I’m still surprised when people argue the idea of ancestral health with “but Grok only lived to 30.”

Another common counterargument is the short average life expectancy at birth of hunter–gatherers. The problem with this marker is that it is influenced by fatal events (eg, accidents, warfare, infections, exposure to the elements) and childhood mortality. Today, average life expectancy is higher not because of a healthier diet and lifestyle but owing to better sanitation, vaccination, antibiotics, quarantine policies, medical care, political and social stability, and less physical trauma.

Common characteristics of ancestral lifestyle

As the authors make clear in their conclusion, it’s not just diet that is involved, but multiple lifestyle factors:

• Regular sun exposure (except for the Inuit, whose very high intake of vitamin D3 from fish and marine mammals may have rendered the lack of ultraviolet-stimulated cutaneous vitamin D synthesis less relevant)
• Sleep patterns in synch with the daily variation in light exposure
• Acute as opposed to chronic stress
• Regular physical activity, as this was required to obtain food and water, to escape from predators, for social interaction, and to build shelters
• Lack of exposure to man-made environmental pollutants
• Universal fresh (generally unprocessed) food sources as depicted in Table 4

Agricultural & Industrial Revolutions

Interestingly (especially for Weston Price fans), the authors suggest that of the two, our modern industrial diet is far more problematic than a grains-based agricultural diet.

The Agricultural Revolution began about 11,000 years ago in the Middle East, later spread to other regions of the globe, and drastically altered the diet and lifestyle that had shaped the human genome for the preceding 2 million plus years. Some of the more significant dietary changes were the use of cereal grains as staple foods, the introduction of nonhuman milk, domesticated meats, legumes and other cultivated plant foods, and later widespread use of sucrose and alcoholic beverages.

Nevertheless it was the Industrial Revolution (with the widespread use of refined vegetable oils, refined cereal grains, and refined sugars) and the Modern Age (with the advent of the “junk food” industry, generalized physical inactivity, introduction of various pollutants, avoidance of sun exposure, and reduction in sleep time and quality coupled with increased chronic psychological stress) that brought about the most disruptive and maladaptive changes, which may have serious patho-physiological consequences. For instance, chronic psychological stress, environmental pollution, and smoking are associated with low-grade chronic inflammation, which is one of the main causes of insulin resistance.

Micronutrient density

It’s not just about macronutrients.

Calorie per calorie, fish, shellfish, meat, vegetables, and fruit present a higher micronutrient density than does milk (with the exception of calcium) and whole cereal grains (and several orders of magnitude higher than refined grains). Moreover, vegetable oils and refined sugars represent more than 36% of the energy in a typical US diet and are essentially devoid of micronutrients (except for vitamin E in some vegetable oils).

Therefore, current food choices, together with soil depletion and modern food transport and stocking, are perhaps the main reasons why a significant percentage of the North American population does not reach the recommended daily allowance (RDA) of various vitamins and minerals.

Anti-nutrients, the gut & inflammation

This section of the paper is fairly techy, but I couldn’t summarize the article without mentioning anti-nutrients and their role in leaky gut and inflammation.

Some factors contributing to increased intestinal permeability include non-steroidal anti-inflammatory drugs, antacids, changes in gut microbiota, alcohol, lectins, saponins, and gliadin. …

It was recently found that gliadin, a prolamine in wheat (which is a novel food in the human diet in evolutionary terms), increases gut permeability by means of zonulin production in the gut enterocytes. …

Similar to gliadin, many plant lectins are also a recent introduction to the human diet. Lectins are omnipresent proteins found in the plant kingdom and likely evolved as toxic defensive mechanisms to ward off predators. Most of these glycoproteins are believed to be benign and nontoxic to humans, but the ones that can bind gut tissue may be problematic, such as those found in cereal grains, legumes, and certain solanaceous plants (tomatoes and potatoes). …

Another class of anti-nutrients that may increase intestinal permeability in humans and hence endotoxemia are saponins, which are present in some cereal grains, legumes, quillaja, alfalfa sprouts, and solanaceous plants such as potatoes and green tomatoes. These steroid glycosides or triterpenoids are formed by a sugar compound (glucuronic acid, glucose, or galactose, among others) and an aglycone (nonsugar molecule) portion. By binding the cholesterol molecule on gut cell membranes, the aglycone portion disrupts the gut barrier and increases intestinal permeability.

Unfortunately, the effects of lectins and saponins on intestinal permeability, endotoxemia, and inflammation have been poorly studied in humans to allow us to draw significant conclusions.

Macronutrient distribution

A diet that isn’t grains-based is generally lower in carbs than the standard Western diet. The authors also clarify (evolve?) their position regarding saturated fats.

Regarding the lower CHO [carbohydrate] content of pre-agricultural diets, it should be mentioned that mounting evidence suggests that a reduced-CHO diet may be superior to a western-type low-fat, high-CHO diet, especially in metabolic syndrome patients, because it may lead to better improvement in insulin resistance, [and other markers]. Nevertheless, because a low-CHO diet is obviously lower in sugars (such as sucrose and fructose) and cereal grains and is often higher in protein, it is unlikely that all of its positive effects can be attributed solely to CHO restriction.

The concern that adopting a pre-agriculture-type diet may encourage a higher intake of dietary fat with a consequent increase in CVD [cardiovascular disease] risk is not justifiable, because the absolute amount of dietary fat consumed is probably much less important than is the type of fat consumed. …

Finally, SAFA [saturated fats], when consumed in the context of a higher-protein, reduced-CHO diet, are not metabolically equivalent to SAFA in the context of the typical western diet or even in the context of a prudent low-fat, high-CHO diet. …

In light of that information, we propose increasing the intake of protein (in the form of fish, shellfish, meat from grass-fed and game animals, and eggs from free-range hens) and cis MUFA [mono-unsaturated fats] (through virgin olive oil, avocados, and nuts), decreasing CHO consumption (especially separated sugars and cereal grains), and maintaining a moderate intake of SAFA.

Omega 3/6

Just a short excerpt, since I’m guessing most people are familiar with this concept.

[I]ncreasing the consumption of omega-3 fatty acids (EPA + DHA) from fatty fish and/or omega-3 supplements, choosing eggs and meats from grass-fed animals (which have a lower omega-6/omega-3 ratio than do grain-fed animal meat and eggs), and decreasing the consumption of LA-rich vegetable oils may be an effective strategy to reduce the risk of various chronic inflammatory diseases.

Conclusion

The authors summarize with the important point that optimal health involves not just diet, but other related lifestyle factors.

[T]he evolutionary template predicts that optimal gene expression, and ultimately an increase in health span (the number of years in good health), even if it would not affect average life expectancy, will not be achieved by any single dietary or lifestyle change but rather through the combination of several measures, such as regular physical exercise; stress management; sun exposure according to latitude and skin color (in order to maintain plasma 25[OH] D above 45 ng/mL and at the same time avoiding the adverse effects of excessive sun exposure); adequate sleep; avoidance of tobacco smoke; reduced exposure to pollutants, dietary AGEs, ALES, and other Maillard reaction compounds; and the adoption of a diet similar to that followed by Paleolithic hunter–gatherers.

Download “The western diet and lifestyle and diseases of civilization” (PDF).