What is it?
The Paleo diet has gained popularity in recent years with its philosophy ‘eat the foods you were designed to eat’ (Cordain, 2012). Speculation about the importance of the Paleolithic diet can be traced back to Bovn Eaton in 1988, as he wrote in the New England Journal Of Medicine, ‘Physicians and nutritionists are increasingly convinced dietary habitats adopted by Western society over the past 100 years make an important contribution to coronary heart disease, hypertension, diabetes, and some types of cancer.’ (Eaton and Konner, 1988). He then went further writing, ‘Problems are virtually unknown among the few surviving hunter gatherer populations whose way of life and eating habits most closely resemble those of preagricultural human beings’. In a later review article, Cordain et al. (2005) outline 7 obvious detrimental changes to diet that have occurred since the Paleolithic era (in the last 10,000 years). These are summarised as follows;
- Glycemic load
This is a way of quantifying how much an individual’s blood glucose will increase based on a defined amount of carbohydrate consumed. It is well established eating foods with a high glycemic load (e.g. white bread) compared with a low glycemic load (e.g. a banana) can lead to insulin resistance, this is related to developing; type II diabetes, hypertension, obesity, and coronary heart disease, we can call these ‘diseases of civilisation’.
- Fatty acid composition
The modern Western diet has too many trans and saturated fats with too few omega6 fatty acids compared with omega3 fatty acids. High levels of trans and saturated fatty acids increase the risk of cardiovascular disease by increasing total and LDL cholesterol. The 6 major sources of saturated fatty acids in the United States diet are fatty meats, baked goods, milk, cheese, margarine, and butter. Of these, all but fatty meats, would have been outside the Paleolithic man’s diet. Additionally, the lean nature of wild animal meat compared with domesticated would have meant lower saturated fatty acids in our ancestors’ diets. A high omega6 to omega3 oil ratio which is related to disease and inflammation is due to higher intake of vegetable oils and meat from grain fed animals.
- Macro nutrients
In the U.S.A. percentage of food energy is derived from the following; carbohydrate (51.8%), fat (32.8%), and protein (15.4%). However, it is known that hunter gatherer populations have increased relative protein (19-35%) and decreased carbohydrate (22-40%). A low carbohydrate and high protein diet has been found to improve insulin sensitivity and prevent muscle loss in obese women. Additionally, clinical trials have shown calorie restricted, but high protein diets are better in promoting weight loss in overweight persons compared with calorie-restricted and high-carbohydrate diets.
- Micro nutrients
Refined sugars and vegetables oils because they comprise a considerable amount of the average modern Western diet and either contain none or very few beneficial nutrients displace important vitamins and minerals. Additionally, the emphasise on grains and milk in our diets, foods of lower relative nutrient content, displace fruits, vegetables, seafood, and lean meats, which have higher nutrient contents. This begun in the Neolithic era as farming became more common, but became worse as cereal milling methods in the Industrial era produced bread flour devoid of more nutrient dense germ and bran. The general displacement of more nutrient dense foods (vegetables, fruits, seafoods, and lean meats) by less nutrient dense foods (refined sugars, grains, vegetables oils, and dairy) has led to depletion in the population of essential vitamins and minerals.
- Acid to alkali balance
Post digestion, absorption, and metabolism, typically foods break down to either acid or alkaline compounds that are released into the circulation. Fish, meat, eggs, poultry, dairy, and cereal grains are acid producing foods. While fruit, vegetables, tubers, nuts, and roots are alkaline producing. Legumes are neutral. Typical modern Western diets have a net acid load and as a result have a low grade pathogenic metabolic acidosis. That gets worse as kidney function declines. The Paleolithic diet is an alkaline diet because of the absence of cereals and nutrient poor foods that were introduced in the Neolithic and Industrial eras. An alkaline diet has many benefits that include preventing age related muscle wasting, osteoporosis, calcium kidney stonese, exercise induced asthma, and hypertension.
- Sodium to potassium ratio
The introduction of manufactured salt to the food supply and the displacement of potassium rich foods during the Neolithic and Industrial eras has resulted in a 400% decrease in potassium intake and a 400% increase in sodium ingestion. A low potassium and high sodium diet is implicated in causing or aggravating hypertension, stroke, osteoporosis, colon cancer, asthma, and kidney stones.
- Fibre content
The mean fibre content of the normal U.S. diet (15.1 g/d) is considerably lower than recommended (25-30 g/d). Refined sugars, dairy, vegetable oils, and alcohol are all devoid of fibre and make up 48.2% of the energy intake in the average U.S. diet. Refined grains are the most popular in the U.S. and they contain 400% less fibre than whole grains. Fresh fruit contains twice the fibre of whole grains and non-starchy vegetables approximately 8 times. Wild grown fruit and vegetables are known to contain considerably less fibre than the domesticated equivalents. Again, we see that there has been a displacement of fibre-rich plant foods by new staple foods during the Neolithic and Industrial eras. Fibre increases the rate of bowel movements and decreases the risk of chronic constipation. Chronic constipation is persuasive in our modern society and is thought to underlie the development of many diseases.
Other problems with non paleolithic foods
Gluten and dairy can aggravate the immune system
Beyond the nutritional problems of a non Paleolithic diet, there are also immunological disorders that have emerged, especially those related to breads and dairy. Obvious examples are celiac disease (Kaukinen et al., 2002) and lactose intolerance (Swagerty et al., 2002). Celiac disease is an autoimmune condition related to gluten in bread that involves the adaptive immune system (Fasano et al., 2015). There are also people with non-celiac allergies to gluten that also involve the adaptive immune system. However, it has become apparent that gluten can cause digestive upset in patients without either celiac disease or gluten allergies, this is called non-celiac gluten sensitivity (Biesiekierski et al., 2011). Non-celiac gluten sensitivity is a recent term and it refers to a non-allergic response to gluten, that may be driven by the innate immune system (Fasano et al., 2015). This can lead to various problems that include IBS and it is even linked to psychological illnesses and autoimmune diseases. However, firmly grounded in the Paleolithic diet theory is the idea that our health problems cannot be blamed on a single molecule and breads are complex carbohydrate based foods. They are not fibre rich compared with fruits and vegetables, when evolving we would not have consumed these types of foods.
Dietary lectins may aggravate the immune system of pre-disposed individuals
Common non Paleolithic dietary foods such as cereal grains and legumes contain glycoproteins called lectins (Cordain et al., 2000). It is thought, wheat-germ lectins can bind surface molecules on intestinal epithelial cells this can cause structural damage to the villi. These structural changes may lead to functional changes including increased intestinal permeability which may facilitate the passage of undegraded dietary antigens into systemic circulation.
In genetically susceptible individuals, the antigenic stimulation may lead to the triggering of autoimmune diseases such as rheumatoid arthritis via molecular mimicry. Molecular mimicry is a process whereby foreign peptides, similar in structure to internal peptides, may cause antibodies or T-lymphocyte cells to cross-react with both foreign and endogenous peptides. This can lead to tolerance for self-peptides being broken and autoimmune disease develops.
Foods included in the paleo diet:
Vegetables, fruits, nuts and seeds, grass (not grain) fed meats, wild seafood.
This is a plant based diet, around 80% vegetables and fruits, 20% meats.
Foods excluded in the paleo diet:
All grains (including breads, pasta etc), legumes, diary, refined sugar, added salt, processed foods.
Terry Wahls: An example of the paleo diet in action
Terry Wahls developed MS while at medical school and was diagnosed with it in 2000 (Wahls, 2014). By 2003, she needed a wheelchair, had secondary progressive MS, and found the drugs were not working. At this point, she started studying alternative methods for dealing with chronic illness and this led her to the Paleo diet. Using this diet, Dr. Wahls found she could ride her bicycle again after 4 years in a wheelchair. After her success in treating the MS she wrote a popular book called, ‘The WAHLS protocol: A Radical New Way to Treat All Chronic Autoimmune Conditions Using Paleo Principles’. The Wahls protocol is based on the Paleo diet, but has 3 different levels and added restrictions and guidelines. Below is a summary of these levels:
Note: additional guidelines are given about the number of portions, type, and colour of vegetables and fruits, and meal timings in the book.
Level 1: Wahls diet
No gluten or dairy containing food.
Level 2: Wahls paleo
No gluten or dairy containing food. All non-gluten grains, legumes and potatoes are reduced to two servings per week. Dr. Wahls writes it is preferable to remove grains and legumes entirely to reduce carbohydrate load, but also reduce phytates and lectins.
Level 3: Wahls paleo plus
All grains, legumes, and potatoes are eliminated. Starchy vegetables are limited to 2 servings per week or less. Fruit is limited to 1 serving per day. White-fleshed fruits are eliminated, such as apples, bananas and pears, as well as sweeter fruits like grapes, peaches, pineapples and mangoes.
A paleo inspired vegetarian diet
A good option for people who do not want to eat meat, but still want to learn from Paleolithic principles is to use legumes, brown rice, and small amounts of whole wheat and dairy instead, depending on your own sensitivity.
Diet is the foundation of our lives in many ways and also of any sensible strategy to heal the body. The Paleolithic style diet has a lot we can learn from even if we are not all interested in becoming cavemen type people. Personally, I use legumes and rice instead of meat most of the time, but still eat a mostly plant based diet without much wheat and dairy. There is no one diet for everybody, but the Paleo diet is a useful roadmap to better, healthier, eating.
Christopher, John R. School of Natural Healing. Christopher Publications, 1976.
Cordain, Loren, et al. “Modulation of immune function by dietary lectins in rheumatoid arthritis.” British Journal of Nutrition 83.3 (2000): 207-217.
Cordain, Loren. AARP The Paleo Diet Revised: Lose Weight and Get Healthy by Eating the Foods You Were Designed to Eat. John Wiley & Sons, 2012.
Eaton, S. Bovn, and M. Konner. “A consideration of its nature and current implications.” N Engl j Med 312.5 (1985): 283-9.
Kaukinen, Katri, et al. “Celiac disease in patients with severe liver disease: gluten-free diet may reverse hepatic failure.” Gastroenterology 122.4 (2002): 881-888.
Swagerty Jr, DANIEL L., Anne D. Walling, and Robert M. Klein. “Lactose intolerance.” American family physician 65.9 (2002): 1845-1850.
Wahls, Terry L., and Eve Adamson. The Wahls Protocol: A Radical New Way to Treat All Chronic Autoimmune Conditions Using Paleo Principles. Penguin, 2014.