“As I’ve previously mentioned, module 4 started me on this quest to find out exactly what kind of diet humans have evolved to eat over the millenniums.
Finally! I think I may have found the answer. This is a lecture by Professor Loren Cordain about the origins and evolution of the western diet. It is about an 1 hour long with Q & A at the end but I assure you it is well worth the watch. (video at bottom of page)
Although I had to split my viewing times over the course of a few days while commuting to school, I label this kind of lecture “Life-changing” because it has certainly clarified many of my questions about the natural diet for humans.
Main highlights (for those of you who don’t have time to view this):
- Archaeological evidence has shown that homo-sapiens have evolved to eat an omnivorous diet
- This diet consists of minimally processed wild plants and animals that were either gathered or hunted.
- Evidence (more carbon-3 isotopes) from preserved skeletons of ancient humans (tooth) show that they were eating both meat and plant foods
- Stone tools to skin animals or break open bones to obtain brains or marrows date back to 2.6 million years ago
- The Expensive Tissue Hypothesis: ” The expensive-tissue hypothesis suggests that the metabolic requirements of relatively large brains are offset by a corresponding reduction of the gut. The splanchnic organs (liver and gastro-intestinal tract) are as metabolically expensive organs in the human body that is markedly small in relation to body size. Gut size is highly correlated with diet, and relatively small guts are compatible only with high-quality, easy-to-digest food. No matter what is selecting for relatively large brains in humans and other primates, they cannot be achieved without a shift to a high-quality diet unless there is a rise in the metabolic rate. Therefore the incorporation of increasingly greater amounts of animal products into the diet was essential in the evolution of the large human brain. ”
The Expensive Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution. Available from: http://www.researchgate.net/publication/.. [accessed Nov 21, 2015].
- Human colonies that migrated to northern latitudes had to rely on more meat to survive because of sparse foraging food sources.
- These and many more evidence presented in the lecture convinced me that we were not meant to be vegetarian or vegan.
- Some foods that were virtually non-existent in the diets of our ancestors:
– cereals, rice, pasta
– diary products (milk, cheese, yogurt)
– artificial table salt
– refined vegetable oils
– refined sugars (except raw honey)
-domesticated fatty meats (wild meat is very lean compared to domesticated farmed animals. Think deer meat)
- In the western diets, these foods mentioned in above (point 8) comprise about 70% of our plates. Their inclusion displaces that of minimally processed wild animal and plant foods.
- Neolithic food introductions: this is the time period 10,000 to 5,500 years ago when these ‘unnatural’ foods were introduced into our diet. 10,000 years may seem like a long time but is actually only 333 human generations. Thus, we could not have evolved any form of genetic adaption to these foods.
10,000 years ago: agriculture (wheat & barley) and sheep, goats and cows domesticated.
Wine and beer: about 7,000 years ago
First salt mines: about 6000 years ago
Sucrose (from cane sugar): about 2,000 years ago
1798: Table sugar became available to the masses
1858: feedlot produced meats
1888: refined grains – white bread, white rice
1900s: refined vegetable oils (found in almost all processed foods) and hydrogenated oils
1978: High fructose corn syrup
- As our ancestral diet became replaced with these neolithic and industrial era foods (from point 8), they adversely affected the following nutritional components in our diets, contributing to the chronic diseases in the western world:
(1) The glycemic load
(2) Fatty acid balance (omega 6s to omega 3s)
(3) Macronutrient Balance
(4) Trace nutrient density
(5) Acid/base balance
(7) fiber content
- From (1), High Glycemic Load carbohydrates promote diseases of insulin resistance: The metabolic syndrome – type 2 diabetes, hypertension, dyslipidemia, obesity, gout
- Cereal grains are net acid producers and the average western diet produces a slight chronic metabolic acidosis
- Refined grains reduce the trace nutrient density of the western diet
- Both whole and refined grains reduce fiber content: you can get 10x more fiber from vegetables
- The fat profile of wild meats (saturated to mono to poly unsaturated fat ratio) is rather balanced compared to diary which is predominantly saturated with little poly and even lesser monounsaturated fats
- *** Despite the deceptively low glycemic load, dairy products paradoxically have insulin indices similar to white bread! ***
- Prior to agriculture, all animal foods consumed by humans were wild animals and the entire animal (organs included) was usually consumed. This is in contrast to western countries where rarely are meats other than muscle meat consumed.
- Wild meat is much leaner and has a balanced lipid (fat) profile than the fatty meats we consume year round
- Body fat in wild animals waxes and wanes seasonally however with the advent of animal husbandry 10,000 years ago, it became possible to prevent the seasonal decline in body fat % by providing captive animals with plant food year round. It was also possible to slaughter them at peak body fat % since they were always fat.
- Feed lot produced cattle are usually slaughtered at 25 to 30% body fat whereas wild caribou body fat ranges from 3.1 to 6.8 %
- Wild animal meat has up to 3x the amount of Omega-3 fatty acids compared to our domesticated grass or grain fed animals
- Diseases linked to reduced omega-3 fatty acids in our diet:
Metabolic Syndrome which includes cardiovascular heart disease, cancer, autoimmune disease
All inflammatory ‘itis’ diseases
- We eat about 10g of salt in our diet on a daily basis, mostly from processed foods. Even bread has about 1.5g of salt in each slice
- Diseases linked to salt over consumption:
hypertension, stroke, kidney stones, stomach cancer, insomnia, motion sickness, asthma, exercise induced asthma
- About 18.6% of our total energy comes from refined sugars in our diets (oreos anyone?)
- Honey was only available seasonally and humans would consume it in large quantities if they came across it, but not at the rate we are consuming now – year round consumption
- We are currently consuming an average of 140 pounds of sugar per year per person! of which 64.9 pounds consist of high fructose corn syrup (year 2000)
- Diseases linked to refined sugars:
– Metabolic syndrome (mentioned above like type 2 diabetes, CHD, obesity etc)
– dental carries (tooth decay)
– certain cancers
- In 1999, total vegetable oil consumption has increased 459% since 1909, salad/cooking oil consumption increased 1340%,
- Vegetable oils are high in omega-6 fatty acids but low in omega-3s (anti-inflammatory)
- Diseases linked to overconsumption of omega-6 (pro-inflammatory):
Metabolic syndrome (Type 2 diabetes, cardiovascular heart disease, obesity, gout, hypertension)
virtually all inflammatory ‘itis’ diseases
- Recommendations for a modern diet based on Paleolithic food groups:
– fresh veggies
– fresh fruits
– nuts and seeds
– healthful oils (olive, coconut, avocado etc)
– wild fish/seafood
– lean meats
- Additionally, the 10 mins Q&A at the end of the lecture was extremely informative about such topics as gluten and how that leads to a state of perpetual chronic low-level inflammation in our bodies and etc.
I will definitely be sharing this post on my blog (injurednomore.com) and continue to read up and implement the lessons I have learned here in my daily life. Truly, this lecture has been life-changing for me. “
One thought on “Homework-turned-blogpost: Life-Changing Lecture – The Origins and Evolution of the Western Diet”