The Primal Origins of the Human Diet


Deep in the milky-way lies a barely detectable interstellar cloud that contains an 8-atom sugar called glycolaldehyde. This chemical may just be a major precursor to life on planet Earth. Glycolaldehyde can react with ribose, a 5-carbon sugar, to form RNA and DNA. DNA is like a biological blueprint that a living organism must follow to remain functional. RNA helps carry out this blueprint’s guidelines. RNA transfers the genetic code needed for the creation of the proteins that make up pretty much everything in the human body.


Think of DNA as a blueprint or initial set of instructions. RNA contains the second set of guidelines for converting the design into the actual biological residence we live within. Together, DNA and RNA form the basis for life on Earth. Glycolaldehyde is one of the keys to the creation of both of these essential substances.


This same interstellar cloud that we are discussing contains another compound called ethylene glycol, and it is a close relative of sugar. This is an important factor when looking into early life on Earth. In Earth’s earliest days, the atmosphere contained no oxygen. Without oxygen, life was based on the production of energy using anaerobic processes, meaning processes that do not require the presence of oxygen. These anaerobic processes allowed for the conversion of sugars as well as early forms of protein into energy. So you have two out of the three macronutrients covered here, carbohydrates and protein, but what about Fat? Another kind of process was needed to convert fat into energy. This requirement for a new process is a critical concept in understanding how our metabolisms work at their most basic level.

The first living cells were prokaryotic. Prokaryotic cells are microscopic single-celled organisms that have neither a distinct information-rich nucleus, nor do they have any other specialized oxygen-based internal components. This is understandable since in the earliest times life on Earth involved no oxygen. This means that all of the living cells on the planet were identical in their genetic structure. It also means that they primarily metabolized sugar for energy. But keep in mind, this process had a very important side effect!

A comparison of eukaryote and prokaryote cell types

The oxygen that fills our atmosphere today was built up over millions of years as a waste product from the prokaryotic cells’ anaerobic digestion of sugar. Once there was enough oxygen to go around, prokaryotic cells evolved into eukaryotic cells and almost all the life we see each day — including all plants and animals, are Eukaryota. Eukaryotic cells are far more complex and diverse than prokaryotes. They contain a nucleus, which stores a unique genetic blueprint. Eukaryotic cells also boast their own personal “power plants,” called mitochondria. They thrive in an oxygen-rich environment. These tiny cellular substructures produce chemical energy, and they hold the key to understanding the evolution of life on Earth. They ushered in a whole new era. These complex eukaryotic cells eventually evolved into multicellular organisms.


But how did these eukaryotic cells change themselves into more complex life forms? How did such a simple life form make the evolutionary leap from a prokaryotic single cell to a more complex eukaryotic multicellular organism, like a plant or an animal? The answer to these questions is a powerful statement about living a successful life on Earth. Eukaryotic cells evolved through teamwork.


Evidence supports the idea that complex cells are actually the product of separate simple cells that united together to form a union. In fact, our energy-producing mitochondria seem to be the “great-great-great-great-great-great-great-great-great grandchild” of a free-living bacterium that was engulfed by another cell. This bacterium ended up becoming a sort of perpetual houseguest. The host cell benefitted immensely from the chemical energy produced by its new mitochondrial guest. This energy-producing cell structure in turn profited from the shielded, nutrient-rich environment surrounding it.


It is our mitochondria that produce energy by using oxygen to burn fat. Fat is an aerobic nutrient. It forms the very foundation of oxygen-based metabolisms. Fat cannot be used for anaerobic (non-oxygen-based) conversion to energy; only sugar can.


Essential Nutrients, Nonessential Excesses and Disease


We can discuss essential nutrients in two broad categories; macronutrients and micronutrients.

You are what you eat, and you eat what you are: fats, proteins and carbohydrates. You also must consume various other vitamins and minerals. In this episode we will discuss macronutrients first and then we will look at micronutrients.

What are nutrients?

What are micronutrients? Micronutrients are the vitamins, minerals, trace elements, phytochemicals, and antioxidants that are essential for good health. Micronutrients generally get a lot of attention because they can be packaged and bottled (for profit). However, when it comes to health and vitality, it is ultimately macronutrients that run the show.


Nutrition has become a very confusing subject for discussion these days. What follows is basic description of the science behind what the various macronutrients do and what our basic requirements are for their consumption. To be clear, I have strong reservations about the value of manufactured foods. All foods that were not given to us by mother-nature directly, and which require significant processing to consume, should be removed from daily life if your goal is health and longevity. This includes manufactured so-called health foods and commercially prepared factory-farmed meats.

The category of macronutrients can be broken down into two subsections, essential and non-essential. Essential nutrients are nutrients that your body cannot manufacture for itself. Essential nutrients must come from external sources. Non-essential nutrients are nutrients that can be accessed internally or made by combining a variety of other available nutrients. For example, your body can make carbohydrates, also known as blood sugar, internally by breaking down the protein in muscle.

There are essential micronutrients as well. These include the various B vitamins, vitamin C, and the fat-soluble vitamins A, D, E & K. They must be accessed externally. There are also many essential minerals, including: Calcium, Chloride, Chromium, Cobalt (as part of Vitamin B12), Copper, Iodine, Iron, Magnesium, Manganese, Molybdenum, Phosphorus, Potassium, Selenium, Sodium, Zinc. Your body can’t make these essential components either.

Note: There are no essential carbohydrates or sugars, and all of the carbohydrates you eat eventually become sugar. Why are there no essential carbs? Because we can make them via the synthesis of amino acids and glycerol obtained from other metabolic processes. We can also make them through de novo synthesis (also called gluconeogenesis). Eventually, the body can adapt to a low-carbohydrate state by producing ketones (a state called ketosis) to fuel the body/brain. We can readily adjust to using ketones for fuel, except where excessive carbohydrate stores are present. In that case, our bodies will revert to running on sugar.


We do not need carbohydrates. In fact excessive intake of processed sugars is the cause of the major diseases of affluence in the developed world today. These diseases include massive increases in rates of cancer and heart disease. Cutting excessive sugars and carbohydrates out of our diets will prevent a vast proportion of these diseases! We know this fact after observing the effects of fasting and caloric restriction.


Fasting and caloric restriction both reduce levels of insulin and increase insulin sensitivity. Improving these factors will regulate the storage of blood sugar in the form of fat. Eating fat doesn’t make you “gain weight” directly. However, eating excessive amounts of sugar along with dietary fat is what causes us to pack on excessive and unhealthy pounds.

As well, fasting and caloric restriction reduce another growth factor called MTOR. MTOR isshort for mammalian target of rapamycin), which regulates cell growth and cell proliferation. MTOR is a protein sensing pathway.

Caloric Restriction

Caloric restriction, often shortened as CR, extends healthy, average, and maximum life spans. Various longevity studies have analysed many short lived animals, including mice and rats, as well as animals with longer life spans such as primates. These studies follow a variety of species through a full lifespan in a shorter period than is possible with humans. Studies on humans involve less severe parameters over shorter periods for ethical reasons, but their findings parallel those of animal studies. Animal studies conducted over the past 20 years have reliably demonstrated up to a 40% increase in maximum life span through life-long caloric restriction. For more information on this topic, please see the article “Caloric Restriction Delays Disease Onset and Mortality in Rhesus Monkeys” published in the July 2009 issue of Science.


This image shows the appearance of Rhesus monkeys in old age (approximately 27.6 years). A and B show a typical control animal. C and D show an age-matched caloric restricted animal.

Unlike animal studies, human studies of caloric restriction cannot be directly credited with the same impact on life span. This is because we can’t directly study its effects over an entire human life span easily. There are serious moral implications for such research. However, fasting and caloric restriction has been shown provide numerous health benefits. These include lowered risks for most degenerative conditions of aging as well as improved measures of health. In recent years, more lengthy human studies of long-term and short-term calorie restriction have systematically demonstrated these benefits. Many researchers believe that the evidence to date shows the practice of caloric restriction and periodic fasting will, in fact, prolong the healthy life span of humans. There simply isn’t enough data yet to pin down the impact on an entire life span. However, it is reasonable to believe that the impact of caloric restriction could mean a difference of 5-10 years of life. The biological reaction to caloric restriction occurs in most species examined to date. It likely evolved early in the history of life on Earth as a tactic to boost the likelihood of surviving periodic famines. We haven’t always had grocery stores. The effects of such dietary restrictions are the same, whether you are a mouse that is alive for a few years or a human living for many decades.

The beneficial effects of caloric restriction in laboratory animals have been known for more than 80 years. Only in the past decade has a high enough level of funding and attention been given to this field. There are many ways that caloric restriction benefits health, including: increased insulin sensitivity and decreased oxidative stress. It even positively alters levels of the friendly bacteria in your digestive system!

How Caloric Restriction Benefits Health

There are several different ways in which caloric restriction may work. The area that seems to get the most research is related to a family of genes called Sirtuins. There are seven mammalian sirtuins that we know of (SIRT1 through SIRT7). In the last decade, these sirtuin proteins have received a lot of attention as epigenetic regulators of aging. The growing association between aging and neurodegeneration has led researchers to investigate the role of sirtuins as potential targets for the development of novel therapies to prevent or slow down the progression of age-related neurodegeneration – think Alzheimer’s disease.


SIRT1, the most studied member of the sirtuin family, has already been shown to regulate numerous neuroprotective functions, including the antioxidant and anti-inflammatory response. It also plays a key role in the regulation of insulin, gene transcription, and the production of new energy-producing mitochondria. There is a heavy research focus on SIRT1 gene expression because it can be targeted by drugs and by supplements like Resveratrol. But there is a much easier way to regulate this powerful gene expression, and it takes us back to the beginning of today’s discussion.

Simply put, SIRT1 is negatively associated with both MTOR and Insulin. This means that excessive protein consumption, mainly dairy-related proteins, and excessive carbohydrate consumption decrease the expression of our longevity genes. We are complex creatures that use oxygen to create energy. This means that we are built to burn fat, and eat fat. We won’t burn fat if we are eating carbohydrates and sugars. The sensing target for fat in our diets is a hormone called leptin. Leptin acts as the ultimate gene regulator. Sensitive receptors for all three nutrient sensors, leptin for fat, insulin for sugar, and MTOR for protein, encourage the expression of SIRT1 in a positive direction. You cannot abuse these nutrient sensors, or you will lose sensitivity to their effect by building up a tolerance to them. Food can be abused, just like a drug. Since protein stimulates MTOR & insulin, and elevated blood sugar stimulates insulin and leptin, that leaves us with dietary fat as a primary source of fuel.

There are major health & longevity benefits when fat is used as a primary source of fuel. Ketogenic diets have the following benefits:

A well-adapted fat-burning ketogenic metabolism may be one of the best preventative measures you can take against aging and disease. Remember the beginning of our discussion; burning fat is our birthright. When properly conducted, being in ketosis does not involve any sense of deprivation. In fact, for many people being in a state of ketosis is very liberating because they do not need to eat constantly.

There are reasons we are built to burn fat for fuel to create energy.

1. A glucose-based metabolism can’t truly use stored fat for energy generation, at least not until their excess glucose runs out. When there is enough sugar available in the blood, our bodies will use it preferentially over fat. Note here that we are using the term “preferentially”. This does not mean sugar is more effective or efficient for energy production. On the contrary! Carbs have fewer calories than fat to make energy, fat contains 9 calories vs. carbs only having 4. This means you are forced to eat larger volumes of them in order to have enough energy to go around.

2. When someone who is highly dependent on carbohydrates for energy goes a few extra hours without eating, they become very hungry. Think of it as essentially stoking metabolic fires with kindling (energy-light sugar) and not logs of hard-wood (energy-dense fats). Further, clinical studies have even shown that the body fat of carbohydrate-dependent dieters will release stored fatty acids several hours after eating and during periods of fasting. This release of fatty acids is yet another sign that our bodies actually prefer fat as a fuel source, even if it is our own stored body fat! Carbohydrate dependent eaters are simply replacing kindling with kindling without ever tapping into much more efficient sources of energy.

4. Glucose-based metabolism relies on a short-lived source of energy. Glucose will work for you if you need it, but you can’t store very much of it in your body. Even a 150 pound person who’s fairly trim with 12% body fat has 18 pounds of animal fat on hand to be converted into energy. Compare this to our ability to store sugar/glucose as muscle and liver glycogen. We are limited to around 500 grams or so. This means that using glucose for energy need to constantlysupply carbs from an external source, thus stopping the burning of any body fat for energy! Terrible trade-off!

5. A glucose-based metabolism will use up glycogen fairly quickly, even during moderate exercise. That is not to say that glycogen-based exercise and efforts are not of some merit. Depending on the type of physical activity, glycogen burning can be essential and expected. But, it is valuable fuel. If instead, you’re able to stay in an oxygen-based fat-burning mode for as long as possible you can save glycogen for anaerobic “all-out” efforts. Glycogen stores are literally life-saving jet fuel for doing things like running from dangerous wild animals. Sugar-adapted people are wasting their glycogen stores on efforts that fat should be able to fuel.


Fat as a Source of Fuel: Our Evolutionary History


It is our birthright to be strong and lean. Looking at metabolism through the lens of evolution, we can see that fat and protein were the dominant macronutrients, when we were lucky enough to have any food at all. Over our two and a half million years of adaptation, we have sometimes not had regular access to food, especially in the form of glucose creating carbohydrates. This would have caused our ancestors to develop effective ways to tap their own stored body fat for energy instead of relying on a steady supply of carbohydrates. Normally, our activities would not have required the level of energy that sugar can provide. After all, we were usually not in full-blown get me the heck out of here flight mode. As a result, we have a very low level of glycogen, which is stored for emergencies, compared to available fat rations in our bodies. Clearly it was primarily the fats and ketones, with small amounts of glucose generated internally through gluconeogenesis, that supplied us with appropriate levels of energy for healthy day-to-day living.

In Conclusion

Eating is our birthright. The importance of sugars, proteins, and fat in our diets date back to the earliest days on the planet. At a molecular level, it an essential part of our connection to the stars. We are literally built to eat food and create energy. When we follow our natural in-born genetic preferences, we are paid back with the fruits of vitality and longevity. Despite arguments to the contrary, lower carbohydrate diets have been shown, in human subjects, to increase the number of mitochondria available for energy production. Want more energy? Want more clarity? Want less illness and disease? Why wait?


© 2020 by Crane Medicine

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