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May 11, 2014

Paleo diet – traditional hunter and gatherer diet

by Helene van den Berg

Our modern diet, full of refined foods, trans fats and sugar, is the root of degenerative diseases such as obesity, cancer, diabetes, heart disease, Parkinson’s, Alzheimer’s, depression and infertility.

The Paleolithic diet is a modern nutritional plan based on the presumed diet of Paleolithic humans (hunter-gatherers). It is based on the premise that human genetics have scarcely changed since the dawn of agriculture (end of Paleolithic era) and that modern humans are adapted to the diet of the Paleolithic period.

The Paleolithic diet seeks to mimic the diet of pre-agricultural foragers. The Paleo diet consists of foods that can be fished and hunted (seafood, meat) and foods that can be gathered (eggs, fruits , vegetables, herbs, mushrooms, nuts seeds and, spices).

The Paleo diet consists mainly of fish, grass-fed pasture raised meats, eggs, vegetables, fruit, fungi and nuts; it EXCLUDES grains, legumes, dairy products, potatoes, refined salt and sugar and processed oils.

The meats recommended are preferably free of food additives (grass-fed beef and wild game meats), since they contain higher levels of omega-3 fats compared with grain-produced domestic meats. Foods before the Neolithic agricultural revolution are excluded from the diet: mainly dairy products, grains, legumes (beans and peanuts), processed oils (except olive /coconut oil), refined sugar and salt. They recommend to drink mainly water or organic green tea. Eating a wide variety of plant foods is recommended to avoid high intakes of harmful bioactive substances, such as goitrogens, which are present in some roots, seeds and vegetables. The Paleo diet practitioners derive 56-65% of their food energy from animal foods and 36-45% from plant foods. They recommend a diet high in protein (19-35% energy) and relatively low in carbohydrates (22-40% energy) and a fat intake (28-58% energy) higher than the Western diet.

According to S. Boyd Eaton, “we are heirs of inherited characteristics accrued over millions of years; the vast majority of our biochemistry and physiology are tuned to life conditions that existed before agriculture 10 000 years ago. Genetically our bodies are virtually the same as they were at the end of the Paleolithic period 20 000 years ago”. Therefore an ideal diet for human health and well-being is one that resembles this ancestral diet. Natural selection had sufficient time to adapt the metabolism and physiology of Paleolithic humans to the varying dietary conditions of that era, while over the last 10 000 years, since the agricultural era, there was too little time to make the optimal genetic adaptations to the new diet. Physiological and metabolic maladaptations such as diabetes have been seen in Native American populations newly introduced to the contemporary Western diet.

More than 70% of the total daily energy consumed by all people in the United States comes from foods such as alcohol, cereals, dairy products, refined sugars and refined vegetable oils. These foods contributed to little or none of the energy in the Paleo diet and excessive consumption of these Neolithic and industrial-era foods is responsible for the current epidemic levels of cancer, cardiovascular disease, high blood pressure, obesity, osteoporosis, type 2 diabetes in the US and other contemporary Western populations.

The Paleolithic lifestyle included high levels of physical activity in addition to the Paleo diet. Researchers suggest that “human genes evolved with the expectation of requiring a certain threshold of physical activity” and the sedentary modern lifestyles results in abnormal gene expression. Compared to ancestral humans, modern humans often have increased body fat and substantially less lean muscle, which is a risk for insulin resistance. The ancestral humans spent one- third of their caloric intake on physical activity (1000 cal/day out of the 3000 cal/day), which is comparable to the WHO recommended physical activity level of 60 min/day of moderate-intensity exercise.

The Industrial revolution (18-19th century) led to food processing techniques and intensive livestock farming methods, that enabled the production of refined cereals, refined sugars and refined vegetable oils, as well as fattier domestic meats, which have become major components of Western diets. Several key nutritional characteristics of the human diet has been altered since the Paleolithic era, including glycemic load, fatty acid composition, macronutrient composition, micronutrient density, acid-base balance, sodium –potassium ratio and fiber content. These are risk factors in the pathogenesis of chronic diseases prevalent in Western societies.

MACRONUTRIENT COMPOSITION:

  • Protein and carbohydrates:

The increased contribution of carbohydrate, from grains, to the human diet after the agricultural revolution, has diluted the protein content of the human diet. High-protein diets may have a cardiovascular protective effect and an effective weight loss strategy for the overweight and obese. Carbohydrate restriction may help prevent obesity, type 2 diabetes as well as atherosclerosis. (Note: Plant–based carbohydrates is consistent with the Paleolithic era).

  • Fatty acids:

Forager diets maintain high levels of monounsaturated and polyunsaturated fats, moderate levels of saturated fats, as well as a low omega-6 : omega-3 fatty acid ratio. Cows fed a grass-based diet produce significant amounts of omega-3 fatty acids compared to grain-fed animals, while minimizing trans fats and saturated fats.

The small dense oxidized LDL are the real culprits of heart disease, because they are more susceptible to oxidation than the large, more stable good “LDL”. The good LDL is the kind of LDL that increase in some people when they eat dietary cholesterol and saturated fat. Bad LDL can increase when you eat a carbohydrate-rich Western diet. Excess fructose (refined sugar, high-fructose corn syrup), lack of exercise, smoking, excessive alcohol, refined carbohydrates and omega-6 fatty acids can all cause oxidation of bad LDL and “plaque ruptures” causing strokes and heart attacks. Plaque is made up of a high amount of linoleic acid , an omega-6 fatty acid, found in vegetable oils like sunflower, corn oil etc. Damage to the arterial walls caused by a high carbohydrate diet, stress, smoking, high omega-6 to omega-3 ratios and trans fats, are another contributing factor to heart disease. Dietary cholesterol has little to no effect on blood cholesterol levels, therefore the lipid theory (heart disease is caused by high levels of cholesterol in the blood) is false. Also the lifestyle and dietary habits that contribute to heart disease are the same that lead to obesity and diabetes: too many omega-6 fatty acids, which help promote chronic inflammation of the arterial walls; high glycemic foods like sugar and refined grains; and not exercising.

Saturated fat raises the good LDL levels, which doesn’t increase the incidence of heart disease. Coconut oil is a great source of medium-chain-fatty acids (MCT’s), a type of saturated fat that can be used as quick energy in the body. MCT’s have helped people to lose weight. Lauric acid in coconut oil, is a powerful antiviral and can increase HDL.

NOTE: Eating Western foods PLUS fatty animal foods, may increase your chances of creating oxidized LDL and therefore heart disease, because the saturated fat increase LDL and the Western diet oxidizes it.

  • Energy density:

The Paleolithic diet has lower energy density than the typical diet consumed by modern humans. The plant-based carbohydrates (fruits and berries contain 0.4-0.8 cal/gm) and game meat ( cooked wild rabbit -1.7cal/gm), have lower energy densities than processed foods ,like McDonalds Big Mac average 2.4 – 2.8 cal/gram and chocolate bars exceed 4 cal/gm.

Low energy density diets tend to provide a more food and a more satisfied feeling at the same caloric intake and they are effective in achieving weight loss in overweight people without explicit caloric restrictions.

  • Micronutrient density:

Fruits, vegetables, meat and seafood, which are staple food of the forager diet, are more micronutrient-dense than refined sugars, grains, vegetable oils and dairy products. The vitamin and mineral content is much higher compared to the standard diet. Fish and seafood is a rich source of omega-3 fatty acids and other micronutrients, such as iodine, iron, copper, zinc and selenium , that are crucial for proper brain function and development. Nuts (almonds) and leafy greens (Kale, dandelion greens) are very high sources of calcium, compared to the calcium-poor grains and legumes of the Western diet. The low calcium amounts in plants are more easily absorbed than the high calcium amounts in dairy. Modern humans require much more vitamin D than foragers, because they do not get the same amount of exposure to sun. Today some dairy products are fortified with vitamin D. To avoid deficiency, people on a forager diet have to take supplements of vitamin D or be exposed to mid-day sun twice a week for 30 minutes.

  • Fiber content and glycemic load:

The Paleolithic diet involves a consumption of 1.65-1.9 kg of fruits and vegetables, substantially higher than the current U.S. intake of 15g/day. Fiber intake in preagricultural diets have exceeded 100g/day. Unrefined plant foods have low glycemic indices. Dairy products like milk, also have low glycemic indices, but are high in insulin indexes, similar to that of white bread; BUT fermented milk products, like yoghurt, has organic acids that counteract the insulinotropic effect of milk in mixed meals.

  • Sodium-potassium ratio:

People in the Paleolithic era consumed 11 000 mg of potassium and 700 mg of sodium daily. The U.S. diet, with it’s dominance of sodium over potassium, adversely affects cardiovascular function and contributes to hypertension and stroke.

  • Calcium and acid-base balance:

Diets containing high amounts of animal products, animal protein, processed foods and other foods that increase the acidity of body fluid, may contribute to the development of osteoporosis, renal stones, loss of muscle mass and age-related renal insufficiency, due to the body’s use of calcium to buffer pH. The Paleo diet may not contain the high levels of calcium recommended in the U.S. to prevent these effects. HOWEVER the ancestral forager diet , with it’s absence of energy-dense and nutrient-poor foods and base-yielding fruit and vegetables, produce a net base load on the body, as opposed to a net acid load, which reduce calcium excretion.

  • Bioactive substances and anti-nutrients:

Legumes, milk and cereal grains, contain bioactive substances (gluten and casein), which creates various health problems. Wheat, barley and rye, contain gluten, which has adverse health effects on people suffering from gluten insensitivities, including celiac disease. The Paleolithic diet is devoid of cereal grains and is therefore gluten-free. The Paleo diet is also casein-free. Casein, a protein found in milk and dairy products, may impair glucose tolerance in humans.

Cereal grains and legumes contain high amounts of anti-nutrients (protease inhibitors, alpha-amylase inhibitors, lectins, phytates), which interfere with the body’s absorption of many key nutrients.

Lectins in seeds of plants protect the plant against “predators” causing diarrhea, nausea, bloating, an immune response, “leaky gut” etc.

Phytates/phytic acid aren’t digestible by humans, because we lack the enzyme phytase to break them down. Phytates bind to magnesium, calcium, zinc and iron in your intestines and REMOVE it from our bodies… which could be the cause of iron–deficiency anemia (less iron), muscle cramping in PMS (less magnesium), immunity problems ( less zinc) and less of bone-building and nerve transmitting calcium. Soaking and pressure cooking legumes (even our nuts and seeds) can remove most of the harmful lectins and phytates.

Molecular-mimicking proteins (amino acids that resemble a total different protein) are found in grains and legumes, as well as milk and dairy products. This promotes vitamin and mineral deficiencies and may explain the development of chronic diseases and autoimmune-related diseases.

The first human randomized controlled clinical trial involving 29 people with glucose intolerance and ischemic heart disease, found that those on a Paleo diet had a greater improvement in glucose tolerance and was more satiating per calorie compared to those on a Mediterranean diet.

In another clinical study on type 2 diabetes patients, the Paleo diet resulted in lower values of tricylglycerol, diastolic blood pressure, body mass index, waist circumference and higher values of HDL (high density lipoprotein) compared to the Diabetes diet. The Paleo diet was also lower in total energy, energy density, dietary glycemic index, saturated fatty acids and calcium, but higher in unsaturated fatty acids, dietary cholesterol and some vitamins.

 

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