Its so important to understand what we’ve evolved to eat. This way things become clear as to why we are struggling with energy, weight and disease. I find knowledge is key to understand what your body needs. Instead of listening to advertisers for advice on the right things to eat, read about our history with food, then decide whats best.
Why diets don’t work
A weight loss diet is defined as a regime of eating whereby we eat fewer calories than we need and consequently break down stored body fat to use as energy. Whether you opt for counting calories, or go on the latest fad diet, you are depriving your body of the energy it needs, and it will do everything it can to make up that deficit in order to preserve your energy, your health and even your life.
Because of our normal physiology, weight loss diets cause you to put on more weight in the long term. In fact, 95-98 percent of people who lose weight by reducing calories by whatever method end up regaining the weight lost and putting on more for good measure. This is inevitable when you consider how the physiology of the human body works, and how we evolved to deal with food shortages, which is exactly what a reducing diet is – a food shortage.
Our Stone Age ancestors were forced to endure famines when food was in short supply. A layer of fat was a survival mechanism that provided energy during these enforced fasts. People with little fat, perhaps coupled with a high metabolism, couldn’t survive these fasts, and so died out, leaving the successful humans (us) as the ones who could successfully adapt to fasting by developing fat stores during times of plenty and being able to lower their metabolism in order to use less energy when food was in short supply. We have evolved to use our body fat to survive.
Our ancient ancestors found it hard to get enough fat or sugar in their diet, so they didn’t develop a mechanism that stopped them eating too much fat or sugar; there was no need for one. They ate all they could get in the form of meat and fruit, with the occasional seasonal treat of honey, and their bodies stored any excess as energy stores of body fat. Obesity was unheard of in our ancient ancestors. Women needed extra fat storage capacity to see them through the extra demands on their bodies from pregnancy, so it is easy to see why women put on weight more easily, and why it is harder to shift it. Our bodies are very efficient at storing fat and absorb around 95 percent of the fat from our food intake, while almost 100 percent of the sugar is absorbed. So, our bodies have evolved to be highly efficient at fat storage; in fact, we have evolved many mechanisms in the body that are designed to encourage weight gain and prevent weight loss. Our bodies have not yet learned to cope with a modern diet or learned to compensate for the high-calorie food we eat, so obesity continues to rise.
When we diet, we initiate this ancient natural survival mechanism, and it resets our metabolism at a lower level in order to protect our fat stores. When the famine or diet is over, and we start eating more food again, our bodies increase our fat stores and add a bit extra for good measure in readiness for the next famine. Thus, a cycle of yo-yo dieting becomes established.
When we diet by cutting calories or skipping meals, we crave food. When we restrict the amount or variety of foods we eat, such as when we follow fad diets, we also experience cravings, which is another ancient inbuilt mechanism designed to give us all the nutrients we need from various foods in order to stay healthy.
Our hunger and satiation sensors in our stomach still tell us when we have eaten enough, by the weight of food and the feeling of fullness in our stomach, but instead of pounds of low-calorie healthy vegetables, we are filling our stomachs with high-calorie refined foods. Pound for pound, you could either eat a pound of vegetables for about 100 calories, or a pound of chocolate cake for 2,500 calories. Either way you satisfy your hunger, but our bodies can also detect the chemicals and substances contained in the food we eat. We are satisfied with less of the healthy, nutrient-dense foods, since these are packed full of the correct nutrients our bodies need. Refined and processed foods, however, are full of calories but short of nutrients, so our body requires more and more of these foods in order to get enough nutrition. The result is that we overeat refined high-calorie foods and become overweight. When you overeat compulsively on processed foods, you are responding to your body’s need for nutrition.
Another problem with dieting is that once the body uses up its fuel reserves, it will start to break down muscle tissue as well as fat. Muscle boosts the metabolic rate and uses more calories than fat, and so when you lose muscle you also lower your metabolism, making it even harder to lose weight. People who are continuously on a diet end up having more fat than muscle, and every time they regain weight after a diet they just get fatter and fatter, and it becomes increasingly hard to lose weight. The more muscle mass you have, the higher your metabolism, which results in more calories being used as energy, even at rest. You can increase muscle mass with weight bearing exercises such as walking and weight resistance training.
What our human ancestors ate
Around 3.75 to 3.2 million years ago, a descendant of modern humans – Australopithecus aferensis, also known as ‘Lucy’ – was found in Africa. Lucy walked upright and ate a traditional primate diet of fruit and vegetation, insects and possibly small animals. The diet was varied, with more than three hundred different species of plants, insects and animals on the menu. This provided a diet rich in protein and nutrient-dense foods, including fat. The early human digestive tract and dentition had become adapted to this diet over millions of years of primate evolution prior to this.
About 2.5 to 2 million years ago, during the Palaeolithic era, a later descendant – Homo habilis, or ‘Handy man’ – was found in Africa, and it appears that this early human ancestor used primitive tools to scrape and cut meat from animals that were scavenged, and to break bones and skulls in order to obtain bone marrow and the brains of animals killed by predators such as lions. The addition of more meat and protein to the diet was instrumental in allowing the large brain of our human ancestors to develop and triple in size. The scavenged brains would have been particularly nutritious since they contain an omega-3 fat called docosahexaenoic acid, DHA, which is the building block of our brain tissue. Without this, the human brain would not have expanded and we would not have become the sophisticated animals we are today.
Later, around 1.8 to 1.6 million years ago, Homo erectus appeared in the fossil record of human ancestry. Also called ‘Java man’, he had the largest brain yet of the human or primate lineage, and used up to 25 percent of his daily calorie intake to fuel this brain (monkeys use just 8 percent). His diet included not only scavenged meat, killed by other animals, but H. erectus also actively hunted wild animals for meat. H. erectus was so successful that he outlived all other humanlike species on Earth at that time, surviving until around 300,000 years ago.
Ancestral humans ate the most varied diet of any primate, and it was probably the most nutritious diet of any animal on Earth. It was so successful that there began to be a division of labour among humans, women gathering fruit, leaves, nuts and wild plants while the men hunted animals and continued to scavenge meat.
Between 500,000 and 180,000 years ago, Homo sapiens, or archaic humans, gradually replaced H. erectus and lived alongside other early humans such as Homo neanderthalensis, or Neanderthals as they have become known. H. sapiens lived in communities and were very social, bringing food back to a home area rather than roaming the countryside. They had mental maps of the best places to find food and hunt animals, and had created special killing areas where they drove large prey over cliffs, so that they would fall to their deaths and provide huge amounts of meat for the whole community. The human population began to grow, and early humans began to share and barter for food and other provisions, possibly because of the great variety of food they ate in their diet. Humans began to settle into a more sedentary lifestyle. By 30,000 years ago, other human ancestors, such as H. neanderthalensis, died out and left H. sapiens as the lone humans on Earth.
Our own species, Homo sapiens sapiens, evolved by 40,000 years ago during the Stone Age or Neolithic period. They looked almost exactly as we do now, except they were leaner and fitter and had barely any signs at all of tooth decay (just 2 percent of fossil teeth show decay). They were also taller than we are today, and continued to forage for vegetation, fruit and nuts, and hunt wild animals for meat as their ancestors had done.
As time went on the human population grew, the wild animals they had hunted became extinct, and Stone Age man, for one reason or another, began to grow food from seeds and store it for use during the harsh winter. By about 10,000 years ago, they began to keep wild animals as pets and use them for food, and the road to domestication of animals and plants began, changing the diet of humans as never before. Within about four to six generations, just 200-300 hundred years, man had cultivated three of the seven core grains, which were chosen not because of their nutritional value but because they were easy to grow, harvest and store.
The Agricultural Revolution
Around 12,000-10,000 years ago, hunter-gatherers became farmers. The Agricultural Revolution occurred. Cereal grains were adopted as a staple diet and animals became domesticated. This was a mere 500 generations ago, barely enough time for genetic changes to keep pace. In the natural world, evolutionary adaptations take millions of years to evolve, and yet humans, with our large brain and higher intelligence, have fast-forwarded our cultural evolution. However, our genetic makeup and our physical bodies have not had a chance to catch up. Our bodies are trying to cope with a diet of modern foods they are not adequately evolved to cope with. As a result, it is believed that this is why humans are suffering the so-called diseases of civilization, including obesity, heart disease, hypertension, diabetes, insulin resistance, cancer, food allergies, food intolerances and eating disorders.
Before Stone Age man began to domesticate and cultivate his food, hunter-gatherers obtained about 30-35 percent of their nutrition from animals, and the other 65-70 percent from plants. We know what they ate from archaeological and fossil evidence, the analysis of the nutritional values found in wild plants and animals, and by studying the few modern hunter-gatherer tribes left today. Fossils show the type of teeth and the patterns of wear our ancestors had, from which an analysis of their diet can be made. Fossilised pollen found around archaeological sites can show what plants were once found there. Analysis of the proteins in preserved hair can identify the diet that was eaten, while the many and varied stone tools found at sites give other valuable clues as to the diet of our ancestors.
They ate a huge variety of wild plants (there are up to 100,000 edible wild plants on Earth), and although some 3,000 were used as food, only 150 plant species were cultivated. Now we live on fewer than 20 main crops, such as maize, wheat, barley and oats. And while the early farmers cultivated wild grains, modern processing only uses the inner starchy endosperm of the grain, which is devoid of nutrients and fibre.
The few vitamins and minerals they do have actually disrupt the metabolism of bone minerals such as Vitamin D and calcium in our bodies, leading to diseases such as rickets and osteoporosis, where grains are the main source of calories in underdeveloped countries. Processed grains contain so little goodness, vitamins and minerals that manufacturers have to fortify cereals and breads with them. Fortifying food should not be necessary, and it certainly isn’t when you eat wholesome, natural, unprocessed foods.
Furthermore, cereals even contain chemicals known as antinutrients, which actually prevent nutrients being absorbed, causing diseases of the gastrointestinal tract. Starch from grains is mixed with fat, sugar and salt to produce a host of convenience foods with a very high calorie content. The only variety we get in our modern diet is how many different ways we can eat processed grains, such as in crackers, noodles, pastas, bread and biscuits. Even ‘wholemeal’ and ‘wholegrain’ flours may be unhealthy. Granted, they may be marginally better than highly processed white flour, but they still have a relatively high glycaemic index and can contribute to diet-related diseases, including obesity and compulsive overeating. Grains are not necessarily good for your health; they are simply a cheap way to mass-produce food.
Natural unprocessed foods are full of vitamins, minerals and phytochemicals. Phytochemicals are compounds that prevent cancer, protect against ageing and heart disease, and probably boost the immune system. Our ancestors must have eaten large quantities of these phytochemicals, yet on the levels of fresh fruit and vegetables we eat, we are barely getting a third of the phytochemicals our bodies need for healthy functioning.
Our ancestors also ate a huge variety of wild animals; now we have just a few domesticated species that we routinely eat. Instead of the diverse diet of our predecessors, modern humans subsist on a poor selection of over-processed food and domesticated meat full of fat, because the animals are sedentary and fed on cereal-based diets, pumped full of antibiotics and other chemicals that were not present in the wild animals that were hunted just 500 generations ago. Often we do not eat the natural cuts of meat but derivatives of it, such as beefburgers, hamburger, hot dogs and corned beef that are padded out with processed starch.
Sugar is the scourge of the modern diet. Refined sugar (sucrose) was unheard of until some 200 years ago, and is another major player in the catalogue of diet-related diseases in modern humans. Modern man eats a staggering 30-40 teaspoons of refined sugar every day! Sugar is found not only in the obvious foods, such as sweets, sugary drinks, biscuits and cakes, but also hidden in baked beans, sauces, flavoured yoghurts, cereals and many, many other processed foods.
Refined sugar is off the scale as a high glycaemic index food, and is responsible for much of the obesity and chronic disease that is such an intractable problem in society today. We also have a real problem with tooth decay that our ancestors didn’t have to worry about. Tooth decay has gone up from 2 percent in Stone Age man to 95 percent in modern man, thanks to our sugary diet. We probably eat more sugar in a day than our ancestors ate in their whole lives!
The problems of agriculture
We may be able to produce larger quantities of food per acre of land thanks to agriculture, but we have lost the amazing diversity in our diet that allowed humans to become large-brained intelligent creatures in the first place. Modern humans are effectively suffering from malnutrition. During the post-Agricultural Revolution, this relatively poor nutrition caused health defects such as vitamin and mineral deficiencies, which we still see today. Diseases such as beriberi and Vitamin B deficiencies became common and persisted into the 1800s until the cause was isolated as a nutritional deficiency. Blindness and skin conditions developed because of a lack of dark leafy vegetables and liver that provided Vitamin A in abundance in the hunter-gatherer diet. Rickets developed because of a lack of Vitamin D. Tooth decay was rare prior to agriculture, but became rife, along with anaemia, brittle bones and stunted growth. Height dropped by about 4-6 inches on average, a good indicator of nutritional status. Infectious diseases such as typhus, smallpox, tuberculosis, bubonic plague and measles spread, and the human immune system was suppressed because of poor nutrition and the close proximity and poor sanitation of people living in large communities. The unique characteristic of the human species, a large brain, also suffered because of agriculture and the poor nutrition that resulted from it. Brain size began to decrease, and even today, the average brain of a human is around 11 percent smaller than those of our ancestors prior to the advent of agriculture.
There were many other problems caused by agriculture. The need for labour on the farm meant that more children were born to provide help. They were also weaned earlier to allow mothers to work on the farm and because children were born closer together. Prior to agriculture, babies were breast-fed for years, but early weaning suddenly deprived children of vital nutrition in their developing years. Infant mortality increased, and because bones were so brittle owing to a lack of calcium, malformations of the pelvis were common in women. This was such a problem that it was advocated by medical doctors in the 1880s that pregnant women deliberately retard the growth of their babies by restricting calories and fluids to make birth easier when there were these bone problems.
Prior to agriculture, the human population on Earth was around five to ten million, but farming unleashed a human population explosion – an exponential increase in human numbers that has ultimately led to the problems encountered today by squeezing seven billion people on the planet. More and more land was turned over to farming, which subsequently destroyed the natural habitat and the lifestyle of our pre-agriculture ancestors forever.
The Industrial Revolution and afterwards
In the late eighteenth and early nineteenth centuries, the Industrial Revolution further changed human lives through the mechanisation of farming, which reduced the need for physical activity. Labour-saving transport and equipment has reduced calorie expenditure in humans by over 60 percent. We are sedentary in the extreme when compared to our early ancestors. Following the Industrial Revolution, we were able to refine sugar and flour, transport food and develop food-processing techniques such as canning, which led to further refinements in our diet. By the mid-twentieth century, food processing included modified fats, and this, combined with the variety of additives, colouring agents, emulsifiers and preservatives, gave us the mind-boggling array of processed foods we see today.
In the 1950s, saturated fats were linked to heart disease, high blood cholesterol and hypertension. Unfortunately, red meat was wrongly implicated as unhealthy and became a scapegoat for heart disease and bowel cancer. So called ‘healthy alternatives’ were developed, such as polyunsaturated margarines and vegetable oils, but we now know that these polyunsaturated fats contain high levels of omega-6 fatty acids at the expense of the healthy omega-3 fatty acids. The use of these margarines and spreads introduced trans-fatty acids into our diet, which was very bad news indeed. Following this, another big mistake in the nutritional guidelines was replacing saturated fats with starchy carbohydrates such as bread, cereals and potatoes. Now, the glycaemic index is a measure of how different carbohydrates affect blood glucose levels. Low-glycaemic carbohydrates, which include natural carbohydrates such as fruit and vegetables, are good for our health and cause a minimal or slow rise in blood glucose. The high-glycaemic index carbohydrates, such as refined and processed sugars and starches, cause a rapid increase in blood glucose and contribute to diseases such as Syndrome X, which includes mature onset diabetes, insulin resistance, hypertension, heart disease, obesity and high LDL cholesterol levels (bad cholesterol).
The results today
Today we eat too little protein (in fact only half the amount our ancestors ate); too many processed foods and high-glycaemic index refined carbohydrates instead of natural carbohydrates such as fruit and vegetables, not enough fibre in the form of fresh fruit and vegetables, and too much of the wrong sort of fat and not enough of the good sort (omega-3 fats are the good sort). We also take in too much salt and not enough potassium. Our ancestors ate a diet rich in potassium and low in sodium (up to ten times as much potassium as sodium). Salt was probably introduced with farming as a preservative for meat and other food. Now our salty diet gives us twice as much sodium as potassium, which is unhealthy. The acid-alkaline balance of our diet has also been altered, and this can affect our health. Our ancestors ate lots of fresh fruit and vegetables, which are alkaline, and lots of meat and fish, which are acid.
This balanced out and was the correct acid-alkaline base for our bodies. Now, however, we eat too many acidic foods, such as dairy and salty foods, and not enough alkaline foods, causing a shift in the acid-alkaline base towards acid. This acidity causes hypertension, the risk of kidney stones, bone and muscle loss, as well the exacerbation of asthma as we age.
In terms of evolution, there has been virtually no time for our bodies to adjust to the radical changes in our diet. Our genetic makeup is more than 99 percent identical to that of our primate ancestors before humans, and 99.9 percent of our genes are identical to our human ancestors of 10,000 years ago. In fact, the human genome has changed less than 0.02 percent in the past 40,000 years.
For 100,000 generations humans lived on wild foods, gathering vegetation, fruit, nuts and seeds, as well as scavenging and later hunting wild animals. Since the advent of agriculture, people have been farming and growing their own food for just 500 generations, and since the Industrial Revolution, when mechanisation saw an explosion in food processing, it has been just ten generations. Computers have been around for one generation, yet our bodies are still genetically adapted to the diet of wild food eaten by our human ancestors some 10,000 years ago.
The quality of modern life has certainly improved from that of our ancestors in certain respects: improved sanitation, medicine, science and technology are able to overcome diseases, reduce infant mortality and lengthen lifespan considerably. But the diseases of civilisation are still generally a modern phenomenon: some 70 percent of cancers and more than 50 percent of heart disease are caused by diet and lifestyle. Obesity is on the increase, reaching crisis proportions, and is undoubtedly linked to an unsuitable diet and an inactive lifestyle. Food intolerance and gastrointestinal disorders, from minor indigestion to serious conditions like bowel cancers, are all too common and are known to be linked to diet and lifestyle.
Stone Age man undoubtedly had his share of health problems, and living wild can be a dangerous occupation with the constant fear of becoming prey to wild animals. However, we can make comparisons when we look at the few modern populations of hunter-gatherers that are left in the world, and even people in modern societies who eat lots of fruit and vegetables. These people rarely suffer from heart disease, cancers, diabetes, stroke or hypertension.
They also have lower rates of depression, anxiety or suicide, and obesity is unheard of. They stay lean and fit, with no loss of memory or mental ability as they age. Yet when these people are brought into a modern society and adopt a modern diet, their physical and mental health and well-being begins to deteriorate, and they develop these conditions within just one or two generations. We also know that ancient humans were strong, lean and fit.