When it comes to food, the concept of a 'balanced diet' appears to be something almost mythical. The balanced diet we talk about continues to change and even though we are supposed to eat a balanced diet in the 21st century, as our understanding of nutrition improves - and as the influence of the food companies diminishes - the definition of a balanced diet will change again.
The quality of the Western diet has been consistently decreasing during the past five decades. Although authorities continually refer to the 'well balanced diet', it becomes increasingly difficult to identify let alone achieve this diet, as our food quantity and quality change over time. A well balanced diet in the 1960s is different from a well balanced diet in the 21st century. Even more so, it is substantially different from that of a fisher-hunter-gatherer some 20,000 years ago, which is where our digestive system has evolved to after more than 220 million years of mammalian evolution.
Our bodies are virtually the same as they were at the end of Palaeolithic period 20,000 years ago; hence the changes in food staples and processing have negatively altered our nutrient balance.(1) As our digestive and renal systems have not changed significantly since prehistoric times, it has been suggested that it would be best for our health if our diet conformed as closely as possible to that of our hunter-gatherer ancestors.(2) This is very different from what most people would classify as the so-called balanced diet.
Our genetic make up, shaped through millions of years of evolution, determine our nutritional and activity needs. Although the human genome has remained primarily unchanged since the first Agricultural Revolution 10,000 years ago, our diet and lifestyle have become progressively distant from those of our ancient ancestors, to the point where our ancient ancestors would be unlikely to identify anything in our modern diet as 'food'.
Evidence suggests that this mismatch between our modern diet and lifestyle and our Palaeolithic genetics is playing a contributory role in the ongoing epidemics of obesity, hypertension, diabetes, atherosclerotic cardiovascular disease, Alzheimer's, cancer and other chronic illnesses. Until 500 generations ago, all humans consumed only wild and unprocessed food foraged and hunted from their environment. These circumstances provided a diet high in lean protein, polyunsaturated fats (especially omega 3 fatty acids), monounsaturated fats, fibre, vitamins, minerals, antioxidants and other beneficial phytochemicals(3, 4) and lots and lots of digestive enzymes. It was a diet consisting of mainly beans, nuts, fresh fruit and vegetables, and fresh hunted game meat and fish, low in total and saturated fat.(5,6)
Anthropological studies show hunter-gatherers to be healthy, fit and free of cardiovascular disease(7) and any other form of suffering of civilisation.(8) This is very different from the shorter, sicker versions of agrarian populations who became dependent upon grains in the past few thousands of years.
The changes in food staples and food processing procedures during the past 10,000 years, but mostly over the past 100 years, fundamentally altered seven crucial nutritional characteristics of our ancestral diet of the Palaeolithic period (10,000 years to 2.5 million years before present). By far the biggest change has been the move to a grain-based diet. In most Western nations this is a single grain: wheat. Today there are three grains that make up 75% of the world's grain production: wheat, rice and maize.(9) These three grains provide between 40% and 90% of our dietary source of energy, protein and fibre.(10) However, we have not evolved as grain eaters.
Wheat was given a huge boost by the US government in the 1950s. The US Department of Agriculture invited food industry executives to participate in drawing up the 'four food groups'. The regulators "felt that food industry groups would have a vital interest in any food guide sponsored by the government".(11) Indeed, the food industry was interested, and delighted when both dairy and grains each scored an entire food group! Kellogg's, General Mills and Post rushed to bring cereals and other grain-based foods to the market.
Nearly a half century later, the food industry still held sway over what the government told people was "good" for them. Luise Light, a nutritionist who drafted early versions of the 1992 food pyramid, stated: (12 )
Our recommendation of 3-4 daily servings of whole grain breads and cereals was changed to a whopping 6-11 servings forming the base of the Food Pyramid as a concession to the processed wheat and corn industries. Moreover, my nutritionist group had placed baked goods made with white flour -including crackers, sweets and other low-nutrient foods laden with sugars and fats - at the peak of the pyramid, recommending that they be eaten sparingly. To our alarm, in the "revised" Food Guide, they were now made part of the pyramid's base.
In addition to raising the incidence of obesity, many other health conditions are linked with increasing consumption of grain, with the most widely known being coeliac disease. Coeliac disease is an inflammatory condition of the gastrointestinal tract, which is associated with the consumption of wheat.(13) In Australia, one in 251 people suffers from coeliac disease,(14) although that number is probably extremely underestimated; the number is one in 87 in England(15) and one in 133 in the US(16) When wheat or other grains that contain gluten are consumed, symptoms that may appear include: upper respiratory tract problems; fatigue; depression and anaemia;(17) and neurological complications such as cerebellar ataxias, dementia, peripheral neuropathies, myopathies and degenerative central nervous system disease.(18) Some of the diseases associated with coeliac disease are listed in Table 1. It is interesting to note that gluten, the offending material in people with coeliac disease, is frequently added to some breakfast cereals to increase the protein content - it is the one protein that should not be added.
Table 1. Diseases that may occur simultaneously with coeliac disease. Source: Cordain 1999.(9)Addison's diseaseAphthous ulcerationAsthmaAtopic diseasesAutoimmune thyroid diseasesChronic active hepatitisDental enamel defectsDermatitis herpetiformisEpilepsy with cerebral calcificationsInsulin-dependent diabetes mellitusLiver diseasesPrimary biliary cirrhosisPrimary sclerosing cholangitisRheumatoid arthritisSelective IgA deficiencySjogren's syndromeSystemic lupus erythematosus
Our modern diet is vastly different from that of our Palaeolithic forebears in a number of respects. The modern consumer eats more fat and sodium and less omega 3 fats, potassium, calcium, magnesium, chromium and other minerals.(19) Fat intakes of greater than 20 g/day (11% of total caloric intake) developed after the domestication of mammals and then by selective breeding of genetically fatter animals.(20) By the late 1940s, the percent of fat in the human diet rose to more than 40% in many Western countries.(21)
Whenever it was ecologically possible, hunter-gatherers consumed high amounts of their energy from animal food (45% to 65%) and the rest from plant sources (22% to 40%). But this was after they expended huge amounts of energy running down their meat and working all day preparing and gathering. The long periods without eating meat were equally important and the meat they ate was very different from the meat we eat today.
The Australian Aboriginal diet, which contained a high proportion of animal foods, was lower in saturated fat with a higher proportion of polyunsaturated fatty acids, especially naturally occurring omega 3 fats. The diets of the South African bushmen were much more nutritious than our modern day diet. This was evident when the nutritional status of 51 adult Bushmen from northeast Namibia, who had been forced to abandon their traditional hunter-gatherer lifestyle and merge with pastoral and urban dwellers, was assessed. Their height was severely diminished and arm muscle was reduced by 75%. Blood tests showed low plasma vitamin C, folic acid and vitamin A and E concentrations compared with native controls. Plasma protein concentrations suggested a high frequency of chronic liver disease, 85% had pulmonary tuberculosis and nutritional depletion was universal.(22) Welcome to a 'balanced' modern diet.
Taken away from their hunter-gatherer way of life, the Aboriginals of Australia and Bushmen of Namibia show little chance of long, healthy lives; in fact it is the exact opposite. We need to learn from these studies and take on a more food-based approach to nutritional education using ideal diets as the model - such as the hunter-fisher-gatherer diets, Indigenous Aboriginal nutrition, the traditional Mediterranean diet and the traditional Japanese diet(23) and not the modern versions. The agrarian diet, introduced some 10,000 years ago, led to a decline in height and life expectancy. There was less danger but more disease. Like our modern diet, it was a convenient way to feed the population, but far from a balanced diet.
References:Mann 2004Withnell 2004O'Keefe and Cordain 2004Haenel 1989Milton 2000Cordain et al. 2000Walker et al. 2003American Society for Clinical Nutrition 2000Cordain 1999Eaton and Eaton 2000Nestle 2007http://www.whale.to/a/american_food_pyramid.htmlFe... et al. 2006Hovell et al. 2001West et al. 2003Fasani et al. 2003Hunter 2003Hadjivassiliou et al. 2002McCarty 1996Garn 1997Naughton et al. 1986O'Keefe and Lavender 1989Truswell 1998
DISCLAIMER: Dr Peter Dingle is a researcher, educator and public health advocate. He has a PhD in the field of environmental toxicology and is not a medical doctor.
Dr Peter Dingle (PhD) has spent the past 30 years as a researcher, educator, author and advocate for a common sense approach to health and wellbeing. He has a PhD in the field of environmental toxicology and is not a medical doctor. He is Australia’s leading motivational health speaker and has 14 books in publication.