Summary: The diet we evolved with is characterized by unprocessed or barely processed small animals, seeds, roots and tubers, seafood and wild fruits. We ate anything and everything that was in the environment we were in, altho'  preferred foods, such as meats were  irregularly supplied,  and some highly preferred seeds were too time consuming to prepare to be eaten in great quantity.
The time time lag from harvest to consumption was often almost zero, and the range of plant and animals eaten was much greater than today. Today's nutritional guidelines are historically based on intake of vitamin and minerals that are sufficient only to prevent the onset of realtively immediate and outwardly obvious deficiency disease. Times of high mineral and vitamin demand are now beginning to be recognized, but the effect on vitamin needs in time of stress is not . Nutritional guidelines are not based on the 'normal' vitamin and mineral level, fat type or composition, of the ancestral foods we hunted and gathered from the wild. In addition, today's natural food may not have the same vitamin content as wild fruits and foods - storage of some natural foods causes decline in the vitamin content over time.
Industrial food is highly attractive, delicious, and displaces whole foods which are more evolutionarily correct. The range of natural foods is now very much less, and we are conditioned to avoid the most nutritious organ meats in the available range.
Some of the best foods, such as fish and organ meat, are being affected by heavy metals we have put in the environment.
A fairly natural diet can be arranged in the industrial west, but it takes informed choice, costs more, is slower to prepare, and is increasingly been seen as 'odd' or 'aberrant', especially by children, who have almost no idea of what foods the omnivorous human animal has evolved with. Most of us cannot answer the question, 'what is natural food for the human animal'?

How do we answer this question? Most of our beliefs about what food even is are conditioned by the country, socioeconomic group, and family we are born into. Born in rural China, I would recognize frogs ovaries, lizards, ducks feet, rice, dried bean curd, lotus waterlilly seeds and roots, dog flesh, pig flesh, fried grasshoppers, fried water beetles, and dried gourds (amongst a huge range of other plant and animals) as being food. Born in industrial England, I would recognize fried potato, fried fish, a stabilized biofoam of wheat endosperm (white bread), pizza, pasta, pies, hamburgers, chicken, crisps and other stabilized and processed plant and animal products as being 'what food is'. Many children-and some adults-no longer recognize what they are eating as being modified seeds, or modified plant oils, modified starches and gums.

Urban society is built on cheap food. Without cheap food, we cannot live in cities. City life is built on stable, easily and quickly prepared food. Our ability to do uninterrupted, applied work in an industrial/service complex in the interests of the shareholders of the industrial/service machine we are currently bound to requires minimum time to prepare food, minimum time to eat food, no mess, and no fuss.

In my opinion, the healthiest diet for the human animal is one we have been eating for the 2 million years prior to urbanization. That is, a wide range of minimally processed plant and animal foods. That means our sugars are obtained from fruits and are therefore accompanied by  fiber, gums, vitamins, minerals, and phytochemicals. Our carbohydrates are derived from roots, tubers, rhizomes, and the endosperm of seeds. It means our fats are obtained from animals, fish, and seeds. Our oils are obtained from the whole seeds and nuts we eat, and from plant sources where the oil is easily extracted, such as olives. The oils are fresh, and are unmodified, and contain protective phytochemicals. It means protein is from nuts, seeds, animals of all kinds, and perhaps fermented or enzymatically pre-digested non-human animal milk products.

"My favourite gem of information about connective tissue concerns the digestibility of elastin. During the digestion of meat in the human gut, elastic fibers are broken down by elastase, an enzyme from the pancreas that would not be there if our evolutionary ancestors had not been at least partly carnivorous. In other words, I have never read of the occurrence of elastin in any human food except meat. So if we have evolved a highly specific enzyme, elastase, to deal with elastin in our food, this can only mean that we are the descendants of meat eaters."
-Professor Howard Swatland , in 'Growth and Structure of Meat Animals'.

Rich industrial/technical societies-chiefly Western societies at this time, although other societies will follow the same path as they too become wealthy-eat furthest from a 'human natural' diet, and degenerative disease is a silent epidemic. Coronary heart disease is the leading cause of death in the USA. Sudden blood clots in arteries-strokes- occur in about 500,000 people a year in the United States and for about 150,000 of those people the stroke is fatal. About 2 million Americans daily life is affected by stroke-related disabilities. About 58 million people in the United States have hypertension-a major risk factor for coronary heart disease. Nearly a million cancer cases are found in the people of the United States every year. Approximately 11 million Americans have diabetes, the severest forms of which causes kidney damage, limb damage, and other cardiovascular damage. 34 million adults-and increasing numbers of children-are obese, a risk factor in coronary heart disease. 1.5 million broken bones a year have been identified as partially caused by weak and brittle bones due to osteoporosis. It is estimated 20 million Americans over the age of 45 are affected by osteoporosis. The American experience is the most extreme example of a people afflicted by degenerative disease. But the pattern is the same for all Western societies.

Most people would not contest that a sedentary lifestyle, exposure to carcinogenic chemicals, and an insecure, high stress environment are part of the causation of this epidemic. The proportion of blame that can be attributed directly to the diet the West eats is difficult to quantify. But the evidence from studies on mice (breeds genetically prone to develop heart disease given food with or without important antioxidants) points starkly to the involvement of a highly modified techno-industrial diet in the cause of cardio vascular diseases. Studies on the particular diets of populations around the world and the incidence of degenerative disease in those populations points to diet and degenerative diseases being strongly linked .

Why should we be surprised that the kinds of food we evolved with protect us from degenerative disease? Why should we be surprised if a diet that meets-and exceeds-our caloric and protein needs, but does not have the kinds, proportions, and levels of fats, oils, minerals, vitamins, and phytochemicals that are found in abundance  in a whole plant and animal food diet is implicated in degenerative disease? Isn't the slow onset of degenerative disease more likely as we move further away from our evolutionarily correct diet? Surely commonsense tells us degenerative disease is less likely the more we eat the kinds and quantities of foods that we evolved to eat over the countless millennia of human evolution? All other things being equal, its just commonsense. It doesn't need 'scientific proof'.

We are confused and bemused by a plethora of studies on diet which contradict each other.

The biggest arguments seem to be over fat. Virtually all fats found in natural foods are basically mixtures of saturated, monounsaturated and polyunsaturated 'fatty acids' in different proportions. Beyond the absolute need to take in at least 2-3% of your fat as the omega-6 fatty acids and at least 1-1.5% as omega-3 fatty acids, there is no one 'formula' of various proportions of fatty acids that everybody in the world 'must' follow, except that it should be the fats found in unprocessed natural foods that would have been available to our hominid ancestors. Nor should fats be an 'ideal' percentage of your calorie intake that must not be exceeded. Larger (naturally large, not due to obesity) or more active people need more calories from fat, and that's about it.

If you eat more calories than you burn, you will store them as fat. Fat in itself doesn't make us fat, excess calories from whatever source make us fat. Excess carbohydrate-whether potato or pasta-is converted to fat and stored. No matter how naturally derived, how 'authentic' to our ancestral diet, excess calories are dangerous in the long term. Period.

At times when our ancestors had only limited access to saturated fats from wild animals (whose fat contains the essential fatty acids Omega-3 and Omega-6) they ate more nuts and seeds and vegetables, which contain enough of these essential fatty acids for our bodies to be able to manufacture saturated fats. Our bodies need saturated fats to make 'structural' adipose tissue, and to burn for energy.  Whether they ate saturated fat from animals or made it from nut and seed mono/poly/saturated fats, the kind of fat in the tissues of our ancestors was relatively saturated fat.  The major form of fat our tissues had available to burn (alongside carbohydrate calories) or store for times of shortage was saturated fat. Again, whether we obtained saturated fat by eating animal fat, or whether had to make it within our bodies from plant derived sources, we ended up in both cases with more or less the same amount of saturated fat both stored and available for burning. Saturated fat is not intrinsically bad. Excess calories - from carbohydrate or fat are. Sedentary people - most of us - needs to cut back on excess calories in saturated fats, in oil intake, and in carbohydrate intake. Or get a lot more exercise.

Humans have consumed saturated fats from animals for countless millennia.  Only very recently-in the last few thousand years or so- in  the tropics at least, has easily extracted oil  from coconuts and palm fruit been introduced to our diet. Very stable oils, such olive oil, camellia seed oil, or sesame paste (all of which contain lots of built-in antioxidants and aren't too polyunsaturated), were also introduced. And they were both fresh and 'unpurified'. They were highly valued, and only small amounts were available, so rancidity tended not to be an issue anyway. There was no ability to extract highly polyunsaturated oils from small seeds, or to create the partially hydrogenated vegetable oils that contain 'trans fatty acids' and that are so widely used in the West today.

Our ancestors got the above mentioned essential polyunsaturated fatty acids from the intact leaves, roots, nuts, and seeds that they gathered (some, such as Linum, flax seed, were quite high in the essential fatty acids) and from the organs of the animals they killed, large or small.  The rather unstable polyunsaturated fatty acids didn't go rancid because they were eaten in a 'whole food' state. Naturally present antioxidants protected the fatty acids from oxidation. Some wild seeds have quite astonishing levels of antioxidant. These natural antioxidants are largely absent in a highly processed food.

We need to be aware that the fat profile in grain fed animals is different to grass fed animals. The fat of grain fed animals has less omega 3 essential fatty acids, and more omega-6 essential fatty acids than grass fed animals. If you are reliant on grain fed animal fat to meet a good part of your calorie needs, it may be a good idea to correct the essential fatty acid balance by taking an Omega-3 supplement. Or regularly eat foods particularly high in Omega-3, such as sardines.

In my opinion, the bottom line is to eat whole natural foods to secure the essential fatty acids omega-3 and omega-6 (especially organ meats, nuts, whole seeds, green vegetables, seafood such as sardines) and take an omega-3 supplement if you are not currently eating as naturally aas you would like; don't be concerned about eating fatty animal tissue, but if you don't get much exercise, use fat trimming as an easy means of dropping daily calory intake; and if you are going to use oils, use stable, predominantly monounsaturated oils such as olive oil, or canola oil. And make sure the oils are fresh, and unprocessed.

Do be concerned if your calorie intake-from ANY source- regularly exceeds the calories you burn. Be very concerned. Even if you don't 'look' fat, you will be carrying excess stored fat within your body cavity and muscles. (Conversely, but more rarely, some 'big' looking  people may have dense bones and lots of muscle, but are carrying healthy amounts of fat. A healthy amount of fat is generally recognized as 15% or less of body mass as fat for men, and 22% or less for women. Women must have more fat stored to be able to ovulate and to feed the babies.)

Why do we need to endlessly study the Western industrial diet, as if it were natural to our species? The white jacketed scientist poring over some laboratory mice is a Homo sapiens, the same animal as you or me. And all Homo sapiens are omnivorous animals that have evolved to eat a wide range of animals-from insects to elephants-and a wide range of plants. And for plants in particular, we have learned even to eliminate or de-nature the toxic chemicals some of them contain, by leaching or cooking. Our guide to healthy eating is simply to see what was available to our ancestors to eat, what they ate, what they avoided, what they relished. The predominantly monounsaturated oils mentioned aside, if it wasn't available to our ancestors, tend to avoid it. Add to that our commonsense and the opportunities to exploit equivalently valuable compounded foods from modern food processing ('surumi' seafood sticks, for example), and we have the basis for a healthy diet in an urban environment. Albeit the lizard, frog, grub, turtle component is no longer available to us-and wouldn't be recognized as food even if it were!

The three major difficulties in eating as we have evolved to eat are-

1.  Finding sources of 'certified safe food' animal (incl. sea, and mollusks)  meats, seeds, fruits and vegetables
2.  Finding time to prepare them so they are available at home and at work
3.  Finding the determination to eat 'unconventionally'-a wonderful irony!

The challenge is to make it cheaply, quickly, and easily available to the public. This is the challenge for food technologists-to help with the keeping qualities of food, to help with prepacking and preparing so as to conserve the vitamin and mineral content.

In time, we may even have products with a guaranteed nutrient profile-guaranteed to be equivalent, say, to a wild grass-grazing animal. The kinds and proportions of fats, minerals, and vitamins in a wild grass fed animal could be characterized, and the diets of farmed animals partly manipulated to mimic this wild animal profile.

Change will only happen when there is demand. And 'demand-opportunity' will be met by commerce. But demand is also dependent on education. The best educated members of the global village will be the first to understand the issue-especially as we age- and to make changes in buying patterns. In time, the obviousness of it will become widely appreciated. Change will happen slowly, and in tandem with commerce providing the solutions to easy preparation, fast preparation, and portability of 'evolutionarily correct' food items.

Like everything in life, the decision to alter a lifestyle rarely happens without comment or objection from others around you, and without extra effort or commitment. The most important factor for any change is to make small changes at first, and incremental changes over time. Enthusiasm tends to have a short shelf life, and the best approach is to slowly replace a habitual food selection with a different one. For example replace a mid morning donut with some cold yam (sweet potato). The extra effort is to have cold cooked yam to take to work in the first place, rather than the simplicity of buying a donut. Eventually, specialist 'human natural food' shops may spring up, selling cold slices of yam, taro, potato, cones of 'mushy peas', and so on.

The other important point is not to become a zealot. There is relatively little wrong with eating small amounts of highly processed foods from time to time. It is natural to want to eat so-called 'junk food'-after all, it has been brilliantly designed to appeal exactly to our natural senses. It's what percentage of your diet is made up of these foods that counts (and in the long run, that counts very much). Keep it low. In addition, taking regular antioxidant supplements will help meet any extra antioxidant demand these foods may create, as well as help protect from environmental free radicals.

The scientific debate on diet and disease is tiresome. In my opinion, as far as the diet component of health is concerned, you will not go far wrong if you overwhelmingly eat an omnivorous, fresh, varied, minimally processed, animal and plant based diet such as our ancestors would have found, protect yourself with a vitamin E supplement (unless you eschew ALL processed and modified food and have access to excellent fresh natural foods-a most unusual situation for Westerners, at least). And relax.

Electronic reading

Human evolution - background
'The' Links page for human evolution, JJJ part of the 'Fossil Hominids FAQ' created and maintained by Jim Foley.  Organised into the following categories-General, Neandertals, Museums and Organisations, Fossils and sites, Books and articles, Courses, Merchandise, Miscellaneous, Humor. Fast, uncluttered, authoritatively selected.
http://www.talkorigins.org/faqs/homs/links.html

Evolution of the Human Diet JJJJ outstanding article on the interplay of human feeding ecology and evolution from forest mainly frugivorous ape to us today as a widely adapted omnivorous ape
http://www.naturalhub.com/opinion_right_food_for_the_human_animal_evolution_of_the_human_diet.htm

General theory of the best diet for humans

What is the optimal diet of the anthropoid primate Homo sapiens?. JJJJ A concise and up to date attempt to analyse the human diet using chimpanzee as an analogue and based on the premise the two diets are in fact analogous. Practical transcription of data into modern living.
http://faculty.washington.edu/dehmelt/APD.htm

ArchivesJJJJ of the Paleodiet Listserve mailing list on the diet of  Paleolithic people in contrast and comment with the existing industrial diet.
http://maelstrom.stjohns.edu/archives/paleodiet.html

Effect on blood lipids of switching to a quasi natural diet JJ A study comparing and contrasting the effect on blood chemistry and enzyme systems of a 'normal' (=abnormal) western diet versus a quasi natural diet (organ meat and fish and molluscs were severley limited for reasons known only to the funders and researchers).
http://www.ars.usda.gov/is/AR/archive/oct98/diets1098.htm

Glycemic index of foods, food analyses, human dietary metabolic pathways JJJ Primarily a page of annotated links, but it also has re-analysed raw data highlighting best foods for lowest insulin response, highest omega-3 quantities etc.
http://www.geocities.com/paleolix/

Argument against the 'expensive tissue hypothesis' JJ A short note rebutting the implication that a large complement os seafood/animal food is necessary for infant brain developement where a substantially natural plant based diet is followed
http://www.geocities.com/paleolix/DHAtheories.htm

Insights into our evolutionary diet - Gatherer Hunter Diets
Australian Native 'Bush Food'  JJ A short page listing a small part of the the wild fruit, legumes, herbs and salad crops that the Aboriginal gather-hunter people of Australia ate, and discusses their commercialisation. An interesting small insight into typical evolutionarily correct foods.
http://www.newcrops.uq.edu.au/newslett/ncnl4-7.htm
 

Insect eating
Edible insects JJJ A page of clickable thumbnails that takes you to first rate photos of silkworm larvae, wasp larvae, scorpions, mealworms, giant diving beetles and others, raw, being prepared, and being eaten.
http://www.cyberbee.net/bugeat/

Insect eating: school study topic JJJJ A very good page discussing culture and insect eating, directed at stimulating classroom discussion. Good real life reporting from various cultures of the insects they ordinarily eat.
http://www.uky.edu/Agriculture/Entomology/ythfacts/bugfood/bugfood2.htm

Hunter Gatherer insect eating JJJJ A brief look at insect eating by peoples in Algeria, Australia, and Nigeria and 'modern' insect eating in Japan and Indonesia. Includes references to papers.
http://www.uky.edu/Agriculture/Entomology/ythfacts/bugfood/yf813.htm

Nutritional value of 10 insects JJJJ The relative protein, fat, carbohydrate, iron and calcium content of ten commonly eaten insects compared to beef and fish. Note the comparative iron and calcium contents.
http://www.ent.iastate.edu/Misc/insectnutrition.html

Meat eating
Is mankind a predator? J A 'from the heart' reflection on hunting, food, and modern living.
http://www.geocities.com/RainForest/9585/Hartic.htm #ManPred

Natural Food Guide-Meat  JJJJ An investigation of our evolutionary history of meat eating -what kind of animals did we really eat, how do modern farmed animal meats compare biochemically to the wild meats we ate in our evolution. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_meat.htm

Protein intake and calcium loss JJJJ Discussion by Loren Cordain of the sometimes quoted relationship between high protein intake and calcium loss. On the 'Beyond vegetarianism' site.
http://www.beyondveg.com/cordain-l/prot-calc/prot-calcium-loss-1a.shtml

Marine turtle in Papua New Guinea J Photo of Kiwai people butchering a captured  marine turtle. Marine turtles would have been a seasonally valuable resource in our evolution, as were the herbivorous and fatty dugong (Dugong dugon). Freshwater turtles, on the other hand, were available year round.
http://geogweb.berkeley.edu/GeoImages/Eley/Kiwai/BUTCHTUR.HTML
http://geogweb.berkeley.edu/GeoImages/Eley/Kiwai/CAPDUG.HTML
http://geogweb.berkeley.edu/GeoImages/Eley/Kiwai/LONGNECK.HTML

Nut and Tree Seed eating
Natural Food Guide-Nuts and Tree Seeds JJJJ An investigation of our evolutionary history of tree seed eating -what kind of tree seeds did we eat, how important were they in the foragers diet? It includes some particularly interesting information on edible tree seeds in the wooded and arid Savannah areas of East Africa. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_nuts.htm

Tuber and Vegetable eating
Natural Food Guide- Vegetables JJJJ An investigation of our evolutionary history of vegetable eating -what kind of vegetables did we really eat, how do modern farmed vegetable types compare biochemically to the wild vegetables we ate in our evolution. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_vegetables.htm

Legume and grass seed eating
Natural Food Guide - Legume and grass seed eating JJJJJ An investigation of our evolutionary history of eating seasonal grass crops such as the various wild grains, and our history of eating wild African legume seeds Which species of grass and legumes were present, how worthwhile their harvest may have been, and the history of domestication of grassess is covered. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_grains_beans_seeds.htm
 

Aquatic food eating
Natural Food aquatic food in evolution JJJJ An investigation of our evolutionary history of eating shellfish, marine and fresh water fish, crustaceans and other aquatic animals -what kind of aquatic animals did we really eat, how does the frequency of shellfish and fish consumption affect our health?. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_seafood.htm

A Homo erectus site in Eritrea,  East Africa JJJJ shows early hominids shellfish gathering activities. At the Discovery channel human origins site. An excellent 'slide show' of 20 images details the finds, particularly the page referenced below.
http://www.exn.ca/hominids/pleistocenepark.cfm
Homo erectus dropped her/his hand axe out on the reef while getting oysters- JJJJJ an excellent picture of a hand axe embedded in the fossil reef.
http://www.exn.ca/hominids/slideshow.cfm?Image=15

Kiwai Papua New Guinea reef fishing tool kit photo- J a basket, bamboo spear with multiple wooden prongs, some cordage. Probably typical of fishing gears for tens of millenia or longer.
http://geogweb.berkeley.edu/GeoImages/Eley/Kiwai/FISHKIT.HTML

Fruit eating
Natural Food Guide-Fruit eating JJJJJ An investigation of our evolutionary history of fruit eating -what kind of fruit were available in the environments we evolved in,, how does modern fruit compare biochemically to the wild fruits we ate in the course of our evolution. A Hub discussion paper.
http://www.naturalhub.com/natural_food_guide_fruit.htm
 

Unnatural diets
Beyond Vegetarianism - JJJJJ An enormous, detailed, and labrynthine site on the evolutionarily correct diet. Much space is devoted to demonstrating the logical and factual inconsistancies of a vegetarian belief set, but along the way the evidence for a natural diet is laid in in most astonishing depth and detail. Cannot be consumed in one bite!
http://www.beyondveg.com/index.shtml
 

If you have a page, or an URL with excellent content that ought to be classified here for further reading, please contribute it.

The author rejects any responsibility for any decisions about life, diet, or anything else other than his own. Any action you take after reading the material here is soley your responsibility - seek advice from others, read critically and widely, don't accept everything you read here. You have been warned! Question everything.

Form your own opinion on these matters after reading widely and consulting appropriate professional advice, including advice of medical practitioners and professional nutritionists.