by Dr. David Ryde MB BS FRCP

Summary
The author speculates that Ancestral Man of 3 – 5 million years ago was a herbivore and an opportunist carnivore; man might also have been a coprophagist. Due to extensive regional climatic changes our ancestor totally adapted to the role of gatherer-hunter in order to survive and the use of fire later helped him in this adaptation. It is suggested that nutritional and alimentary diseases and degenerative changes – afflict meat eaters more than vegetarians. Reasons are given for what the author considers to be the human food niche, and these are used to justify a decrease in the consumption of meat and dairy produce. Palaeoanthropological studies support the National Advisory Council for Nutrition Education Consultative Report, better known as “NANCNE Report.”

Discussion
New vegetarians are aware of less digestive discomfort after overeating compared to that caused by an excessive meat meal; they also feel less sleepy. This may indicate that plant products are easier to digest than meat with its fat content and Lucas (1979) records that 100 G plant protein requires 0.25 G hydrochloric acid to be digested in two hours, while 100 G animal protein requires twice as much acid to be digested in 3.5 hours. Since vegans and vegetarians are reported as having fewer peptic ulcers (Walker and Cannon, 1985) than other people there may be a correlation between meat – eating and peptic ulceration.

During periods of abundance most creatures eat a narrow range of appropriate foods. Lions flourish on zebra and wildebeest meat; song birds on worms, grubs, insects, berries’, buds or seeds; waterfowl on pond weed; cattle, sheep, and horses on parts of different grasses; elephants and giraffes on leaves, fruits and twigs; apes largely on fruits and vegetables while the proboscis monkey flourishes on the leaves of a single tree. These niches tend to be transgressed only in time of shortage. What foods then has nature “programmed” for mankind to eat in order to maintain health, growth activity and reproduction? In this article I speculate on what our Pliocene ancestors ate and then relate current eating habits to the nutritional and alimentary diseases and degenerative changes afflicting mankind today.

Introduction
School book and museum art which depict early man as a hunter, may not be correct as once assumed. Jeffs (1969) discusses what humans were programmed to eat, and he concludes that it was naturally occurring foods such as meat, fish, fruit, vegetables and eggs. Boyd and Konner (l9kjB5) state that “from about 24 to 5 million years ago fruits appear to have been the main dietary constituent for hominids”. They continue that since 4.5 million years ago “our ancestral feeding pattern included increasing amounts of meat”.

Compared to other primates Modern Man eats a great range of foods, and this I believe relates more to his use of cutting and crushing implements and to the later control of fire. That raw meat is almost universally cooked to make it palatable, edible and ‘digestible suggests that prepromethean man did not eat it in large amounts. Cooking denatures protein, melts out fat and breaks down the fibrous tissue, making it easier to digest. Carnivores gulp down lumps of meat, their sharpened molars tearing it like scissors for digestion to begin in the stomach. Herbivores with flatter molar-teeth crush the cellulose-walled plant cells, and begin carbohydrate digestion orally with ptyalin (amylase), as occurs in cows, pigs, rabbits and also humans. Today, foods may be pre-digested by cooking and refining, made more socially acceptable and palatable by packaging, flavouring and colouring, and preserved by freezing, additives and irradiation. These foods may already contain herbicides, pesticides, fungicides, hormones and antibiotics. However preservation, packaging and storage for transport and shelf life are social imperatives in today’s world.

Biological Comparisons with Primates
Human teeth are omnivorous in design, yet more closely resemble primate teeth whose possessors live largely on fruit and vegetable plants. Carnivorous jaws tear vertically while herbivores and human jaws swing vertically to tear and laterally to crush. Carnivorous jaws do not have salivary amylase (Ptyalin). Compared to carnivores, herbivore bowel length is proportionately much greater than trunk length (about ten times compared to three times) and the human bowel length more favours herbivory. The appendix is almost exclusive to man, the higher primates, rodents and a few lower mammals and it is a vestigial, herbivorous caecum. Carnivores do not have a caecum.

The DNA differences between gorilla, chimpanzee and man are reported ( Cribbin and Cherfas, 1982) as under one percent. This is less than that between different species of horse. In a casual moment one could mistake illustrations of the gorilla digestive tract for that of the human tract and one may cautiously extrapolate that the human and gorilla digestive systems also function in a similar way. Humans apart, the highest primates, that is the chimpanzees and the gorillas, are described as herbivores and opportunist carnivores, eating mainly fruits and vegetables, but they may also eat eggs, insects, lizards and other small creatures if easily available or when really hungry.

Hamilton and Busse (197 8) have presented a chart of twenty one primates which largely shows that their animal food consumption is inversely related to body weight. The small primate weighed sixty five gram and ate 70% dietary animal matter, the two largest the gorilla and orang-utan weigh respectively 126 and 58 kilogram. They consume one and two percent animal matter; and the human primate stands between the gorilla and orang-utan in weight.

Walker as reported by Griben and Cherfas (1982) has been using the electron microscope to study miniscule abrasions on the teeth of living species and fossils. Walker has shown that the characteristic marks on fossil teeth indicate that Australopithecus robustus ( ancestral man of four million years ago) like the modern chimps was not an omnivore but a fruit eater.

It seems reasonable to suggest that one higher primate was able, several million years ago when the climatic chips were down and the forests receding, to increase its food gathering repertoire by applying its knowledge and skills to hunting away from tree cover. While 1 speculate that homo-sapiens is a more efficient herbivore than carnivore crushing and cooking makes meat more digestible for him. It also enables him to consume amounts in excess of his needs.

In a personal communication Amiel Bennan, Professor of Herbivore Zoology, Jerusalem, writes that “the natural sex and adrenal steroids as well as adrenaline and thyroxine are oxidised in cooking and lose a large part of their biological activity”. Presumably cooking also oxidises most of the injected steroid given to beef-up cattle before slaughter. If some people, women in particular, are sensitive to minute steroid residues, perhaps in “rare” undercooked meat, then the concern I felt on theoretical grounds is supported by Sylvia Lewis an electrologist of 30 years experience. Mrs. Lewis, having pondered the matter for five years, states that if a client goes vegetarian then over one to two years her hirsutism diminishes considerably, the coarse hair becoming downy. Also she has many clients who became hirsute on taking steroid contraceptive pills.

Climatic Changes
Pliocene climatic changes of ice age and drought rendered food-gatherings less plentiful and to survive Early Man began to adapt towards a gathering-hunting existence about three and a half million years ago. Probably Man slowly migrated from Africa and adapted to temperate regions by consuming more high-energy fat foods. The discovery of how to harness fire about half a million years ago, further increased Man’s alimentary options and proved to be a great social and nutritional revolution as was agriculture about ten thousand years ago.

Current Views
Monographs on vegetarians and vegans ( Doyle, Lueas, Moran, Sussman, Yntema) report that these people enjoy their food, are generally slimmer than meat eaters, live a little longer and suffer less alimentary and degenerative diseases. Pixley et al. (1985) report that gall stones occur only half as often in vegetarians as in meat eaters, and Robertson et al (1979) show that the incidence of renal calcium stone disease is related to the consumption of animal protein. Further there is a low incidence of late onset diabetes in vegetarians, and German soldiers fighting on the Russian front-line who, short of supplies had gathered adequate amounts of fresh vegetables had a lower incidence of stomach complaints than home-based soldiers. Indeed colon cancer, hypertension, strokes, heart disease, diverticulosis, tooth decay, piles, peptic ulcers and varicose veins from a larger list of complaints mentioned in the NACNE Report (Walker and Cannon 1985) have all been implicated an modern food related diseases.

Athletic Endurance
Vegetarian nutrition is in no way contrary to an athletic and endurance career, and Paavo Numi is one name among many vegetarians greats. Pritikin (1985) recounts many such endurance records, and it is feasible that endurance prowess is related to the high carbohydrate content of vegetarian food. This is akin to the carbohydrate loading of modern marathon runners. Sussman (1978) writes of a ploughman who once said he needed plenty of meat to give him the strength and endurance to handle his plough all day, yet the ox in whose furrow he trod lived on the grass of the field. In the wild, grazing animals may not have the same turn of speed as their predators but they usually have greater endurance and manoeuvrability.

Nutrition
Yntema (1960) both from personal experience and an extensive literature search states that vegetarian nutrition is compatible with all childhood needs; she adds though “a monthly supplement of Vitamin B12 is desirable”. Sussman in discussing longevity in several quasi-vegetarian societies, quotes medical sources that nutrition rather than genetics is probably responsible and that individuals lead vigorous lives with little degenerative disease in old age. I suggest that vegetarianism may not promote longevity, rather western nutrition may promote the earlier onset of degenerative disease and brevity of life. Herein may lie a practical approach to the exponential increase of enfeebled old age that is afflicting Western society. Biologists have reported that rats with a restricted food intake, which extends the period of immaturity, live twice is long as rats whose food was freely available. The biological time clock it seems is accelerated by fat rather than by carbohydrate (Pritikin) 2.

Weight Reduction
If traditional advice for weight-reduction were effective, there would be few overweight people. By advising patients to eat differently, not less, the author ( Ryde, 1982) has enabled a fair number of patients (regrettably unquantified) with obstinate obesity to lose weight gradually and with little trouble, including an effortless five stones in one year in a female patient. Chewing plentiful amounts of fresh raw food means that people are more likely to achieve satiation. Though half the English population at the age of fifty is overweight, the secretary of a vegetarian society estimates that only three of its one hundred and fifty members axe overweight. That weight-conscious people who become vegetarians are more successful in slimming than their omnivore peers is my experience.

Health and Disease
After a consultant nutritionist confirmed to me in April 1985 a report that four angina patients in America had all lost their symptoms within four weeks of becoming vegans (a cholesterol free diet) I suggested veganism to a patient with a fifteen year history of angina and unable to walk one hundred yards. In one month the angina had almost gone and the patient felt marvellous. After three months he regularly walked four miles. As a side effect he had lost twenty pounds in weight and his systolic blood pressure dropped 55 points. The chronic varicose ulcer in a grossly obese male healed within 3 weeks, being accompanied by a rapid weight loss. This was partly a diuresis since a vegans salt turnover (without bread) is under 1 G daily, compared to the 12 G of an average eater.

After accepting near veganism an obese elderly male reported that the breast tenderness he had experienced daily for 5 years had disappeared within four days and had not returned four months later. These and other rewarding anecdotes relating to late onset diabetes, persistent indigestion and hypertension do not constitute proof but since veganism with supplements and vegetarianism are harmless, there is every reason to explore and exploit them. Not often will patients accept a dramatic food change, but for those who do or partially so the results are often sufficiently rewarding for me to now offer such advice increasingly and sometimes without conventional medication. However, much water will flow under the bridge of experience before such anecdotes may become accepted wisdom.

Are Supplements Necessary?
The deficiencies of veganism are reported as being the B vitamins, particularly, B12, and also vitamin D, and the minerals Calcium and Iron. That vitamin B12 is present in animal but not plant tissues is used to support arguments favouring human carnivory though Fossey (1985) writes that “the eating of excrement occurs among most vertebrates, including humans, who have certain nutritional deficiencies. Among gorillas coprophagy is thought to have possible dietary functions because it may allow vitamins particularly B12 synthesised in the hind gut, to be assimilated in the fore gut”. Not a tasteful subject but human coprophagy is rational in man the primate. Even so supplements before stools seems a social preference. The recommended daily allowance of vitamin D relates to body clothing not to vegan inadequacy.

Pritikin 3 (1985) writes that ”the high protein intake which is common in the developed nations causes a negative mineral balance, drawing calcium from bone, to neutralise the acid products of protein metabolism”. It is those who eat meat who need extra calcium.

Childbirth occurs about once every four years in the Kung people (Leakey 1978) one of the few remaining gatherer-hunter societies. Menstruation in gorillas recurs about 2 years after parturition but may be delayed a further two years by continued breast feeding (Fossey, 1985). It is not unreasonable to extrapolate this to Pliocene women. Kung children are breast fed for two and a half years at least and usually longer. Since menstruation whilst breast-feeding is rare, a major cause of iron deficiency is removed. Fossey states that “free living gorillas giving birth to live offspring eat most if not all of the placenta. They may gain dietary benefits from this as also from eating their infant faeces”. Modern carnivorous society then imposes abnormal conditions on vegetarians and vegans and it is realistic for them to compensate with supplements. Supplements are given in pregnancy and are added to bread and margarine anyway, for everyone’s benefit.

Conclusions
I have woven together strands of personal belief, speculation and fact into a hypothesis with perhaps some fruitful implications for a health-conscious society. My hypothesis is that Pliocene man was a herbivore food gatherer, an opportunist carnivore and perhaps a coprophagist. Adverse climatic changes of ice age and drought forced man to adapt towards a gatherer-hunter existence, and the control of fire increased his carnivore options. Currently mankind is adapting, for better and for worse, to the nutritional changes deriving from the creation of agriculture, animal husbandry and a food industry.

Sadly Modern Man neither gathers nor hunts but adopts a sedentary lifestyle which leads his system into a slow atrophy. The evidence offered is not conclusive but hopefully it will promote interest in the recurring question of what foods are appropriate for mankind. Increasing awareness of the human food-niche raises questions such as:

Which plants are most suitable for humans to eat?

Are the foetus and breasted child adversely affected by modern nutrition?

How do we best acquire vitamins, minerals and -trace elements?

How digestible is raw meat?

Is salivary amylase an indicator of herbivory?

What effect does cooking have on animal hormones and might they affect people?

Does veganism alter mood?

Might fish breeding with unnatural foods, change a fishes unsaturated fat?

Of what significance are vitamins in human faeces?

Concerning human size and weight, does bigger mean better?

What happens to humans when they chronically breach their food niche?

What role should cereals and dairy produce have in human nutrition since both are recent, but significant alimentary acquisitions?

Why are “recent foods” (cereal grains and dairy produce) more allergic than original foods?

To answer the question posed by the title of this article is only to make an informed guess. I believe our Pliocene ancestors were ‘programmed to eat a variety of plant foods such as leaves, fruits, buds, berries, bark, seeds, stalks, tubers, fungi, pulses and nuts, later adding meat and sea food, according to need and locality and occasionally perhaps their own stools. Fire increased man’s options in carnivory and cellulose foods, and agriculture created a food surplus leading to food storage and the growth of societies and so the need to develop a food industry. Originally food did not contain colouring matter, sweetener preservatives, pesticides, antibiotics or hormones; though modern food production and distribution would not be possible without some form of preservation, processing and packaging.

Ancestral Man experienced a different lifestyle to his descendant, hence the need for caution when making comparisons between living then and now. Modern Man’s destructive and addictive habits and his minimal physical activity are unphysiological, productive of excess weight and disease and leads to early degenerative changes. The civilised human lifestyle bears comparison to that of the domesticated animal. If people reduced their animal protein, salt, sugar and fat consumption and compensated with appropriate fresh plant produce they would be closely following the NACNE recommendations. In conclusion I submit that ”yesterday’s food will become tomorrow’s food.”