Post by cjm on Feb 18, 2016 5:17:28 GMT
Let them not eat cake
Low-carb, healthy-fat science / February 12, 2016
Tim Noakes on evolution and real food that builds bigger brains
...
By Rob Worthington-Smith
...
in this series on Prof Tim Noakes’ defence of the low-carb, high-fat (LCHF) diet, examined the reigning belief system that has controlled the dietary customs into which most of us were born. Since the late 1970s we have been told we need to fight our inclination to eat rich, fatty food and that we do too little exercise.
A healthy lifestyle, so goes the narrative, calls for us to eat a balanced diet dominated by good carbohydrates (especially in cereals and grains, fruit and vegetables), and to avoid saturated animal fats.
Prof Noakes, in presenting his defence at this week’s hearing into his professional conduct, is attempting to tell more than just a contra-version of this story. The evidence he has gathered from archaeologists, anthropologists and medical scientists is the story of our entire dietary evolution, from the first homo species (Homo habilis) through to the fake meal revolution that has brought us to our present state of relatively poor health and high medical bills.
In this article, I will summarise this story and attempt to explain, or at least expose, some of the controversial issues that still engage researchers today.
The story of Homo sapiens, from when H habilis first emerged onto the African Savannah, spans some 2.3 million years. It is a story of evolution, or gradual change in posture, height, dexterity, diet, brainpower, civilization and of course, diet, from one generation to the next.
How many generations are we talking about? An important question, for the longer the lineage, the more opportunity for evolution to take place. If we conveniently take a span of 23 years between generations, this part of our evolutionary history should comprise around 100,000 generations (bearing in mind our Chimpanzee ancestor goes back another 300,000 generations). Considering the agricultural revolution dates back around 10,000 years, our evolution since then spans a mere 434 generations, or 0,4% of the total opportunity for adaptation and change.
Read also: Tim Noakes: does the public REALLY need to be protected from him?
In the first of these two epochs, comprising 99,566 generations, the homo genus learned to use tools, discovered fire and of course developed an enormous brain. This is common knowledge. What medical scientist are learning from archaeologists is that our brain development was a virtuous cycle in concert with our use of technology. We started out with enormous digestive tracts (some four times the volume of present day man) required for fermenting plant foods similar to the diet of the great apes. Our teeth were thickly plated with enamel and we spent some seven hours a day chewing.
Once we had evolved to stand upright on the Savannah, we immediately gained an advantage as a hunter. Our upright stance allowed us to see further in the tall grass. But we also evolved the ability to regulate body temperature; firstly through simple mechanical advantage (reducing surface area for radiation, better convection profile for cooling airflow), and then through the development of our ability to sweat and thus make use of evaporative cooling.
Noakes, an acknowledged expert in both sports science and nutrition, supports the hypothesis that this enabled early man to hunt during the heat of the day, when predators were generally resting. By becoming mid-day ‘persistence’ hunters, our ancestors were able to run their prey to exhaustion and gain access to nutrient dense, animal-based foods. Thus we gradually progressed up the food chain, adding more and more animal products to our diet. These products were high in protein and fat and very low in carbohydrates.
Let’s take a quick look at what constitutes nutritious food: Perusal of the USDA nutrition database reveals that most animal-based foods, but especially the organs, are often more than ten times as nutrient-rich as plant diets. Oats, for example, contain zero vitamin A, B or C, while liver paté contains your daily requirement in one mouthful. There is barely any vegetable (with the possible exception of some nuts, like avocadoes and coconuts) that contains the essential nutrients in as concentrated a package as in animal-based foods.
Another dietary fact from the mainstream biology textbook: the only essential nutrients required by humans are fat, proteins (these include all the essential vitamins), minerals and water. Carbohydrate is not an essential nutrient, and the only carbohydrate in the body is in the form of a teaspoonful of synthesised glucose in the blood stream and up to 500g stored as starch (glycogen) in liver and muscle. Most, if not all the daily requirement for glucose is normally made by the liver from fats and proteins, but can also be readily metabolised from carbohydrate food (in fact rather too readily, as we shall see in a forthcoming article).
Back to our evolving diet: Richer nutrients meant less energy required for digestion and more energy available for some other advantage to develop. Apex predators generally develop explosive muscles, powerful claws and talons, outstanding eyesight, or some other physical advantage. It is crucial to understand the nature of the trade-off that has to be made, for there is a finite energy budget. In the case of the early hominids, the energy that became available from more nutrient-dense animal food and the smaller gut required to digest this food, was diverted to the development of the brain.
Read also: Tim Noakes ‘trial’: did HPCSA set him up in a cat ‘n mouse game?
Smarter brains again made us better hunters. At some point in this development we became smart enough to discover and use fire (there is uncertainty as to whether this was well over a million years ago, or more recently). Gaining access to cooked food enriched our diet still more, further reducing the requirement for energy to digest food, in favour of powering accelerated brain development. Thus the ratio has been reversed, resulting in a large brain and a small digestive tract, no longer required for fermenting fibrous starches, but well-adapted to digesting fats and proteins.
It should be noted that there is an alternative hypothesis for why we evolved smart brains: Rather than improving our hunting skills and becoming more carnivorous, it has been argued that our increasing intelligence improved our ability as gatherers, remembering where to find fruit, for example, and developing methods for gaining access to the more nutritious parts of plant food.
The majority view amongst anthropologists is that skills developed on all fronts, but not least of these was our ancestor’s ability as a hunter.
And then, a mere four to five hundred generations ago, the discovery of agriculture completely changed our way of life. The second, modern epoch began and brought us in the blink of an eye – just 0.4% of our evolutionary timeline – to where we are today. We cultivated grains, settled in towns and cities, and made use of diversity in expertise in expanding populations to trade and build civilization as we know it.
How, in such a brief span, while we evolved technology from the wheel to the internet, and from hunting prey to processing staple grains, could we possibly adapt our digestive tract to these new and exotic, starchy foods?
Many researchers, particularly amongst the archaeologists and anthropologists, are beginning to realise that we simply have not adapted physiologically to the new nutritive environment we have created for ourselves, in particular the switch from a diet high in fat and protein to one low in fat and high in carbohydrate.
In Part four, we will look at what has happened to our health during this second epoch. Prepare to have dispelled any romantic notions of a healthy diet amongst the ancient civilisations!
Rob Worthington-Smith is a science and business writer. While his day job is to analyse companies’ non-financial capitals for the responsible investor, he also pursues a wide range of interests including evolutionary biology and behavioural economics. Rob enjoys the challenge of bringing perspective to contentious issues, such as the moral landscape, how to address inequality in a developing economy, progressive approaches to education, parenting (as a widowed, single parent of four), and the science and pseudo-science behind health and nutrition. Rob holds a BSc Honours degree in Agricultural Economics from Stellenbosch University. Disclosure: Whilst as yet undecided on every aspect of the issue, Rob is currently working with Professor Noakes to bring perspective and balance to the current debate on dietary guidelines.
Low-carb, healthy-fat science / February 12, 2016
Tim Noakes on evolution and real food that builds bigger brains
...
By Rob Worthington-Smith
...
in this series on Prof Tim Noakes’ defence of the low-carb, high-fat (LCHF) diet, examined the reigning belief system that has controlled the dietary customs into which most of us were born. Since the late 1970s we have been told we need to fight our inclination to eat rich, fatty food and that we do too little exercise.
A healthy lifestyle, so goes the narrative, calls for us to eat a balanced diet dominated by good carbohydrates (especially in cereals and grains, fruit and vegetables), and to avoid saturated animal fats.
Prof Noakes, in presenting his defence at this week’s hearing into his professional conduct, is attempting to tell more than just a contra-version of this story. The evidence he has gathered from archaeologists, anthropologists and medical scientists is the story of our entire dietary evolution, from the first homo species (Homo habilis) through to the fake meal revolution that has brought us to our present state of relatively poor health and high medical bills.
In this article, I will summarise this story and attempt to explain, or at least expose, some of the controversial issues that still engage researchers today.
The story of Homo sapiens, from when H habilis first emerged onto the African Savannah, spans some 2.3 million years. It is a story of evolution, or gradual change in posture, height, dexterity, diet, brainpower, civilization and of course, diet, from one generation to the next.
How many generations are we talking about? An important question, for the longer the lineage, the more opportunity for evolution to take place. If we conveniently take a span of 23 years between generations, this part of our evolutionary history should comprise around 100,000 generations (bearing in mind our Chimpanzee ancestor goes back another 300,000 generations). Considering the agricultural revolution dates back around 10,000 years, our evolution since then spans a mere 434 generations, or 0,4% of the total opportunity for adaptation and change.
Read also: Tim Noakes: does the public REALLY need to be protected from him?
In the first of these two epochs, comprising 99,566 generations, the homo genus learned to use tools, discovered fire and of course developed an enormous brain. This is common knowledge. What medical scientist are learning from archaeologists is that our brain development was a virtuous cycle in concert with our use of technology. We started out with enormous digestive tracts (some four times the volume of present day man) required for fermenting plant foods similar to the diet of the great apes. Our teeth were thickly plated with enamel and we spent some seven hours a day chewing.
Once we had evolved to stand upright on the Savannah, we immediately gained an advantage as a hunter. Our upright stance allowed us to see further in the tall grass. But we also evolved the ability to regulate body temperature; firstly through simple mechanical advantage (reducing surface area for radiation, better convection profile for cooling airflow), and then through the development of our ability to sweat and thus make use of evaporative cooling.
Noakes, an acknowledged expert in both sports science and nutrition, supports the hypothesis that this enabled early man to hunt during the heat of the day, when predators were generally resting. By becoming mid-day ‘persistence’ hunters, our ancestors were able to run their prey to exhaustion and gain access to nutrient dense, animal-based foods. Thus we gradually progressed up the food chain, adding more and more animal products to our diet. These products were high in protein and fat and very low in carbohydrates.
Let’s take a quick look at what constitutes nutritious food: Perusal of the USDA nutrition database reveals that most animal-based foods, but especially the organs, are often more than ten times as nutrient-rich as plant diets. Oats, for example, contain zero vitamin A, B or C, while liver paté contains your daily requirement in one mouthful. There is barely any vegetable (with the possible exception of some nuts, like avocadoes and coconuts) that contains the essential nutrients in as concentrated a package as in animal-based foods.
Another dietary fact from the mainstream biology textbook: the only essential nutrients required by humans are fat, proteins (these include all the essential vitamins), minerals and water. Carbohydrate is not an essential nutrient, and the only carbohydrate in the body is in the form of a teaspoonful of synthesised glucose in the blood stream and up to 500g stored as starch (glycogen) in liver and muscle. Most, if not all the daily requirement for glucose is normally made by the liver from fats and proteins, but can also be readily metabolised from carbohydrate food (in fact rather too readily, as we shall see in a forthcoming article).
Back to our evolving diet: Richer nutrients meant less energy required for digestion and more energy available for some other advantage to develop. Apex predators generally develop explosive muscles, powerful claws and talons, outstanding eyesight, or some other physical advantage. It is crucial to understand the nature of the trade-off that has to be made, for there is a finite energy budget. In the case of the early hominids, the energy that became available from more nutrient-dense animal food and the smaller gut required to digest this food, was diverted to the development of the brain.
Read also: Tim Noakes ‘trial’: did HPCSA set him up in a cat ‘n mouse game?
Smarter brains again made us better hunters. At some point in this development we became smart enough to discover and use fire (there is uncertainty as to whether this was well over a million years ago, or more recently). Gaining access to cooked food enriched our diet still more, further reducing the requirement for energy to digest food, in favour of powering accelerated brain development. Thus the ratio has been reversed, resulting in a large brain and a small digestive tract, no longer required for fermenting fibrous starches, but well-adapted to digesting fats and proteins.
It should be noted that there is an alternative hypothesis for why we evolved smart brains: Rather than improving our hunting skills and becoming more carnivorous, it has been argued that our increasing intelligence improved our ability as gatherers, remembering where to find fruit, for example, and developing methods for gaining access to the more nutritious parts of plant food.
The majority view amongst anthropologists is that skills developed on all fronts, but not least of these was our ancestor’s ability as a hunter.
And then, a mere four to five hundred generations ago, the discovery of agriculture completely changed our way of life. The second, modern epoch began and brought us in the blink of an eye – just 0.4% of our evolutionary timeline – to where we are today. We cultivated grains, settled in towns and cities, and made use of diversity in expertise in expanding populations to trade and build civilization as we know it.
How, in such a brief span, while we evolved technology from the wheel to the internet, and from hunting prey to processing staple grains, could we possibly adapt our digestive tract to these new and exotic, starchy foods?
Many researchers, particularly amongst the archaeologists and anthropologists, are beginning to realise that we simply have not adapted physiologically to the new nutritive environment we have created for ourselves, in particular the switch from a diet high in fat and protein to one low in fat and high in carbohydrate.
In Part four, we will look at what has happened to our health during this second epoch. Prepare to have dispelled any romantic notions of a healthy diet amongst the ancient civilisations!
Rob Worthington-Smith is a science and business writer. While his day job is to analyse companies’ non-financial capitals for the responsible investor, he also pursues a wide range of interests including evolutionary biology and behavioural economics. Rob enjoys the challenge of bringing perspective to contentious issues, such as the moral landscape, how to address inequality in a developing economy, progressive approaches to education, parenting (as a widowed, single parent of four), and the science and pseudo-science behind health and nutrition. Rob holds a BSc Honours degree in Agricultural Economics from Stellenbosch University. Disclosure: Whilst as yet undecided on every aspect of the issue, Rob is currently working with Professor Noakes to bring perspective and balance to the current debate on dietary guidelines.