A Comparison: Paleo vs. Westernized Diet

Paleo dietary recommendations are based on the principle that any organism, human or otherwise, functions best when it exists amid circumstances similar to those for which its genes were originally selected. Nearly all of our genes, including those pertaining to nutrition, were chosen or refined throughout the million years when our remote ancestors lived as Stone Age hunter-gatherers. True, there have been genetic changes during the 10,000 years since humans adopted agriculture, but too few to invalidate the basic principle –we remain genetic Stone Agers.

Consequently, our biology is still best adapted for a hunter-gatherer nutritional pattern. Fortunately, we now have skeletal, archeological, anthropological and chemical evidence that allows us to identify the foods that fueled a million years of human evolution. For nearly all that time, our ancestors were Africans, and advocates of evolutionary health promotion and maintained that ideal nutrition for humans is what was consumed there just before the “out of Africa” exodus began perhaps in 100,000 BCE.

People then generally obtained about half their food energy from naturally occurring plant sources (fruits and vegetables –little or no grains) and about half from non-domesticated animal sources (game, fish and shellfish). On average, fats and carbohydrates each provided roughly 35% of each day’s calories and protein perhaps 30%. These estimates for protein and fat accord with recommendations (Dietary Reference Intakes) established by the Institute of Medicine (IOM) of the (US) National Academies. The IOM estimate for carbohydrate is 45% – 65%.

Carbohydrate intake then and now differs in both quantity and quality. Americans typically obtain nearly half their energy from carbohydrates but, of this, 35% come from sugar and refined grains with only about 15% from fruits and vegetables. For Stone Agers, nearly all carbohydrate came from fruits and vegetables. That means their intake of fruits and vegetables was twice ours in the 21st Century. The opposite side of the coin: far more sugars and grain-based flour products for us (35%); but for them only a minor amount (of honey ~2%).

Stone Agers consumed grains when other foods were in short supply, but not ordinarily because the milling required to make grain digestible was disproportionately labor-intensive. Despite this, their fiber intake was at least five times ours. Uncultivated fruits and vegetables are far more fibrous than those in today’s supermarkets.

Total fat consumption then and now was reasonably comparable with two exceptions. Our ancestors’ intake of essential fatty acids (DHA, EPA, AA) much exceeded ours now, and the proportions of omega-6 and omega-3 were closer to equal, perhaps 2:1, whereas the ratio at present is about 10:1.

The uncultivated fruits and vegetables consumed before agriculture have been shown to be much better sources of vitamins and minerals than are those available in today’s supermarkets. Consequently, ancestral humans obtained from 2- to 6-times the vitamins we do, and from 2- to 10-times the principle minerals. However, there are two important exceptions. For them, sodium intake averaged less than one gram per day (vs. four grams for us) while potassium then averaged ten grams (vs. 2.5 grams now). They consumed far more potassium than sodium; we ingest more sodium than potassium. This difference in electrolyte intake affects blood pressure. In 25 different societies, studied when they had no access to commercial salt, Na:K intake was similar to that of Stone Agers and the prevalence of hypertension was near nil. In contemporary America, there are 100 million persons who have, or are being treated for, high blood pressure.

Paleo nutritionists recommend that 30% of dietary energy be from protein. Ancestral humans obtained most of their protein from game, fish and shellfish; however, doing likewise in the present would be environmentally unsustainable. For this reason, diets containing lentils, beans, peas, nuts, tempeh, asparagus, spinach, artichokes, edamame and hummus are desirable, as are soy, for the soy-tolerant, pea, and flaxseed milks for their protein content. In addition, relatively unfamiliar foods like spirulina, soybean sprouts and antique “grains” (quinoa, spelt, amaranth, teff) need to become more popular.

Customized Paleo Diet Guidelines

Given these considerations, what should we be eating? Here are three recommended regimens, each designed for different individual circumstances.

• Strong Paleo –for individuals with ongoing health problems, undesirable biomarkers and for some competitive athletes
  Protein: poultry, fish, shellfish, lean red meat
  Plant Foods: all vegetables and fruits, no grains, no added sugar
  Dairy: none
  Alcohol: trial basis
  Fiber: intrinsic + additive (especially soluble)
  Micronutrients: vitamin/mineral and DHA/EPA supplements; minimize salt intake

• Weak Paleo –for those free from health problems and whose biomarkers (BMI, blood pressure, cholesterol, etc.) are desirable
  Protein: poultry, fish, shellfish, lean red meat
  Plant Foods: all vegetables and fruits, whole grains acceptable, no added sugar
  Dairy: milk products acceptable, preferably goat’s milk
  Alcohol: in moderation, especially red wine
  Fiber: intrinsic + additive (especially soluble)
  Micronutrients: vitamin/mineral and DHA/EPA supplements; minimize salt intake

• Sustainable Paleo –best with regard to Earth’s environment
  Protein: chiefly plant; some poultry and sea food
  Plant Foods: heavy on vegetables and fruits, moderate whole grains, no added sugar
  Dairy: some milk products acceptable, preferably goat’s milk
  Alcohol: trial basis
  Fiber: intrinsic + additive (especially soluble)
  Micronutrients: vitamin/mineral and DHA/EPA supplements; minimize salt intake

Evolutionary health promotion and paleo dietary recommendations are inherently logical and conform to current paleoanthropological understanding. Only a few formal nutritional trials have been made and these have been small. Still, these tend to support the contention that eating as our ancestors did promotes good health. Paleonutrition has been called a “fad.” If so, it’s a fad with a million-year background.

S. Boyd Eaton, MD, practiced diagnostic radiology for 41 years. He was an adjunct professor of anthropology and clinical associate professor of radiology at Emory University. Dr. Eaton, an originator of the paleo diet, co-authored the first article examining Paleolithic nutrition in 1985 and the pioneering book, The Paleolithic Prescription: A Program of Diet & Exercise and a Design for Living.