Primates, Hominids and Their Diets
The minutia of this diagram is debated amongst archaeologists and anthropologists. However, the overall point i'm trying to get across is that human evolution happened over a long period of time and had a diverse number of players. Having an understanding of the diet throughout human evolution is of importance if we're going to have a broad understanding of nutrigenetics/genomics.
Many factors govern which foods a species will choose for nutrient acquisition: taste, gut morphology, toxic load, seasonality of the environment - just to name a few. It is imperative to take the following information in the context that Homo Sapiens have a much more advanced culture that has allowed for nutrient acquisition from a variety of sources that has made for 'Choice' and 'Preference' to play a much more important role than say, seasonality. What I mean by this is that a chimpanzee may eat largely fruit and leaves but that does not mean if you put a piece of cooked meat in front of it that it won't eat it because it 'didn't evolve to eat cooked meat'. Chimpanzees don't have the culture that led to fire development and the ability to cook- but one cannot assume from this that they wouldn't thrive off a cooked diet because they didn't evolve the culture or brain capacity to manipulate fire - indeed, cooking can destroy some toxic substances in the chimpanzee diet, such as tannins, phytoestrogens, and goitrogens. When reviewing past primate diets, just because that is what they ate doesn't mean that is most ideal for them in the long run or what they will thrive off of - be careful about making hugely concrete conclusions from past diet data.
Let's take a look at a few of these species whose diet we know most about:
A. Chimpanzees (Pan Troglodytes) - Comparative anatomy can give insights into the phenotypic divergence in digestive physiology between humans and chimps from their most recent ancestor. Two major anatomical structures, the brain and the gut, have experienced a pronounced change since the most recent ancestor of chimps and humans. Genetic changes that led to the human brain are believed to be directly related to genes related to nutrition, because the human brain requires a higher quality diet to meet its energy needs (Leonard, 2007) The human brain is much larger than the chimp brain; the human brain has a cranial capacity of 1400, whereas a chimpanzee male’s is 410 cc (Gould 1974). The human brain is a major consumer of glucose, accounting for about 16% of the basal metabolic rate for a 65kg male (Aiello, 1995). Relative to chimpanzees, humans also have unique relative gut proportions. Humans devote 56% of their gut volume to the small intestine, the main site of carbohydrate and lipid metabolism (Harris, 1989). Conversely, over 50% of the ape gut volume is devoted to the fermentative hindgut (Milton, 1999). Because humans have to accommodate increased energy expenditure to support brain metabolism with a smaller hindgut than chimpanzees, they require a more easily digestible source of energy in their diets (Aiello, 1995). The difference in intestinal morphology between humans and chimpanzees limits the degree to which humans can rely on fibrous plant materials and increases dependency on starches and animal sources for meeting energy needs. Despite a much shorter transit time through the gut, energy-dense foods provide a significant amount of energy for humans (Harris, 1989).The wild chimpanzee diet is characterized primarily by frugivory, supplemented by young leaves, seeds, flowers, pith, insects, eggs and small vertebrates (Fulk, 1992). Fruit accounts for 68% of the diet, but can vary on a daily basis from 40-90%. Because chimpanzees are ripe fruit specialists, they have a relatively high quality diet, consisting of simple carbohydrates that are easily digestible. Leaves generally constitute 28% of the diet but can account for 50% depending upon seasonality. Chimpanzees habitually consume between 40-140 plant species from their environments (Hohmann, 2006). While it is particularly hard to quantify the percentage of the chimpanzee diet coming from animal sources, it is known that termites and the red colobus monkey are used to supplement the chimpanzee’s largely plant-based diet. However, the percentage of animal foods included is relatively insignificant relative to humans (Hamilton, 1978), and the crude protein content has been characterized as consisting of only 9.5% of the total diet (Conklin-Brittain, 1998). Only about 5% of the chimpanzee diet consists of lipids (Conklin-Brittain, 1998). However, this lipid percentage represents the endogenous content within fruits and does not account for the by products of fermentation in the gut, which generally leads to significant portions of free fatty acids for energy production (Milton, 1999 ). Alternatively, humans are suggested to intake between 20-35% of their diets from fat (Dietary Reference Intakes).
Thus, the chimpanzee diet is much higher in simple and structural carbohydrates and much lower in raw protein and lipid content than humans (Conklin-Brittain, 1998). On average, the energy derived from the chimpanzee diet is 1000 kcal/day (Benedict, 1936). Humans, however, vary greatly in energy intake depending on size and physical activity.
B. Hominids - It is believed that early human ancestors ate a generalized plant-based diet, like that of modern chimpanzees. This switched to a much more abrasive diet in the Australopithecus. The many Australopithecus species are believed to have been morphologically designed to consume nuts and seeds with tough shells, as well as underground storage organs such as tubers (Ye, 2011). The Homo genus evolved around 2.5 mya from a common ancestor with the Australopithecines. Homo erectus was the first hominid species to exploit hunting and scavenging techniques to include a larger percentage of animal foods into the diet. Coprolites, aka fossilized fecal matter, found alongside Homo Erectus fossils show that the diet consumed contained a large amount of fiber, as well as some interesting, generally, non-food items such as charcoal, mollusk shell fragments and sand grains. It was during this time that the controlled use of fire helped contribute to the vast dietary modifications. Cooking with fire increases the digestibility of foods that are difficult to extract energy from when raw, particularly, starch-rich foods and meats. Fire allowed for previously inedible foods to be available as sources of energy. (Carmody, 2011). Neanderthals had long been thought to eat an almost solely meat based diet and are considered to have been huge hunters. However, a recent team of scientists from Barcelona and the University of York have found that Neanderthals in Northern Spain cooked and ate plants and may have perceived food as having medicinal qualities. From food particles trapped in Neanderthal dental plaque, researchers found cracked/roasted starch granules, and evidence of cooked wood (indicated by methyl esters, phenols and aromatic hydrocarbons). The idea that they had knowledge of medicinal knowledge of food is derived from the evidence that they were eating yarrow and chamomile, two bitter tasting plants. The diet of Homo Sapiens can be split into two categories, relative to the Neolithic (Agricultural) Revolution. Much of Homo Sapiens’ nutrition acquisition strategy relied on hunter-gatherer techniques before the implementation of domestication and agriculture (Ye, 2011). Estimates of past hunter-gatherer diets have been extrapolated from the modern hunter-gatherer population, known as the Kung. The Kung derive about 33% of their energy intake from animal sources and 67% from plant sources. Over half of all of their calories comes from the lipid-dense Mongongo nut, supplemented by animal foods, tubers, and some wild plants (Milton, 2007). The diet of post-agricultural revolution humans is characterized by a large percentage of calories from starches, particularly grains and tubers. Agricultural also secured a regular source of meat and dairy products for daily human consumption. This dietary shift is generally associated with an increase in sedentarism and excess of energy intake (Ye, 2011).
What sticks out most here to me? Largely plant based diets, a lot of foods that are not in the food supply (insects, worms) and the human requirement for denser energy sources (i.e. meats, dairy and/or starches- grains, tubers, legumes). I always find it interesting that what popular diets tend to exclude are these some part of these latter energy dense sources- you have vegetarians and vegans obscuring meat and other animal products, you have paleo/low carb'ers excluding a lot of the starches.
The minutia of this diagram is debated amongst archaeologists and anthropologists. However, the overall point i'm trying to get across is that human evolution happened over a long period of time and had a diverse number of players. Having an understanding of the diet throughout human evolution is of importance if we're going to have a broad understanding of nutrigenetics/genomics.
Many factors govern which foods a species will choose for nutrient acquisition: taste, gut morphology, toxic load, seasonality of the environment - just to name a few. It is imperative to take the following information in the context that Homo Sapiens have a much more advanced culture that has allowed for nutrient acquisition from a variety of sources that has made for 'Choice' and 'Preference' to play a much more important role than say, seasonality. What I mean by this is that a chimpanzee may eat largely fruit and leaves but that does not mean if you put a piece of cooked meat in front of it that it won't eat it because it 'didn't evolve to eat cooked meat'. Chimpanzees don't have the culture that led to fire development and the ability to cook- but one cannot assume from this that they wouldn't thrive off a cooked diet because they didn't evolve the culture or brain capacity to manipulate fire - indeed, cooking can destroy some toxic substances in the chimpanzee diet, such as tannins, phytoestrogens, and goitrogens. When reviewing past primate diets, just because that is what they ate doesn't mean that is most ideal for them in the long run or what they will thrive off of - be careful about making hugely concrete conclusions from past diet data.
Let's take a look at a few of these species whose diet we know most about:
A. Chimpanzees (Pan Troglodytes) - Comparative anatomy can give insights into the phenotypic divergence in digestive physiology between humans and chimps from their most recent ancestor. Two major anatomical structures, the brain and the gut, have experienced a pronounced change since the most recent ancestor of chimps and humans. Genetic changes that led to the human brain are believed to be directly related to genes related to nutrition, because the human brain requires a higher quality diet to meet its energy needs (Leonard, 2007) The human brain is much larger than the chimp brain; the human brain has a cranial capacity of 1400, whereas a chimpanzee male’s is 410 cc (Gould 1974). The human brain is a major consumer of glucose, accounting for about 16% of the basal metabolic rate for a 65kg male (Aiello, 1995). Relative to chimpanzees, humans also have unique relative gut proportions. Humans devote 56% of their gut volume to the small intestine, the main site of carbohydrate and lipid metabolism (Harris, 1989). Conversely, over 50% of the ape gut volume is devoted to the fermentative hindgut (Milton, 1999). Because humans have to accommodate increased energy expenditure to support brain metabolism with a smaller hindgut than chimpanzees, they require a more easily digestible source of energy in their diets (Aiello, 1995). The difference in intestinal morphology between humans and chimpanzees limits the degree to which humans can rely on fibrous plant materials and increases dependency on starches and animal sources for meeting energy needs. Despite a much shorter transit time through the gut, energy-dense foods provide a significant amount of energy for humans (Harris, 1989).The wild chimpanzee diet is characterized primarily by frugivory, supplemented by young leaves, seeds, flowers, pith, insects, eggs and small vertebrates (Fulk, 1992). Fruit accounts for 68% of the diet, but can vary on a daily basis from 40-90%. Because chimpanzees are ripe fruit specialists, they have a relatively high quality diet, consisting of simple carbohydrates that are easily digestible. Leaves generally constitute 28% of the diet but can account for 50% depending upon seasonality. Chimpanzees habitually consume between 40-140 plant species from their environments (Hohmann, 2006). While it is particularly hard to quantify the percentage of the chimpanzee diet coming from animal sources, it is known that termites and the red colobus monkey are used to supplement the chimpanzee’s largely plant-based diet. However, the percentage of animal foods included is relatively insignificant relative to humans (Hamilton, 1978), and the crude protein content has been characterized as consisting of only 9.5% of the total diet (Conklin-Brittain, 1998). Only about 5% of the chimpanzee diet consists of lipids (Conklin-Brittain, 1998). However, this lipid percentage represents the endogenous content within fruits and does not account for the by products of fermentation in the gut, which generally leads to significant portions of free fatty acids for energy production (Milton, 1999 ). Alternatively, humans are suggested to intake between 20-35% of their diets from fat (Dietary Reference Intakes).
Thus, the chimpanzee diet is much higher in simple and structural carbohydrates and much lower in raw protein and lipid content than humans (Conklin-Brittain, 1998). On average, the energy derived from the chimpanzee diet is 1000 kcal/day (Benedict, 1936). Humans, however, vary greatly in energy intake depending on size and physical activity.
B. Hominids - It is believed that early human ancestors ate a generalized plant-based diet, like that of modern chimpanzees. This switched to a much more abrasive diet in the Australopithecus. The many Australopithecus species are believed to have been morphologically designed to consume nuts and seeds with tough shells, as well as underground storage organs such as tubers (Ye, 2011). The Homo genus evolved around 2.5 mya from a common ancestor with the Australopithecines. Homo erectus was the first hominid species to exploit hunting and scavenging techniques to include a larger percentage of animal foods into the diet. Coprolites, aka fossilized fecal matter, found alongside Homo Erectus fossils show that the diet consumed contained a large amount of fiber, as well as some interesting, generally, non-food items such as charcoal, mollusk shell fragments and sand grains. It was during this time that the controlled use of fire helped contribute to the vast dietary modifications. Cooking with fire increases the digestibility of foods that are difficult to extract energy from when raw, particularly, starch-rich foods and meats. Fire allowed for previously inedible foods to be available as sources of energy. (Carmody, 2011). Neanderthals had long been thought to eat an almost solely meat based diet and are considered to have been huge hunters. However, a recent team of scientists from Barcelona and the University of York have found that Neanderthals in Northern Spain cooked and ate plants and may have perceived food as having medicinal qualities. From food particles trapped in Neanderthal dental plaque, researchers found cracked/roasted starch granules, and evidence of cooked wood (indicated by methyl esters, phenols and aromatic hydrocarbons). The idea that they had knowledge of medicinal knowledge of food is derived from the evidence that they were eating yarrow and chamomile, two bitter tasting plants. The diet of Homo Sapiens can be split into two categories, relative to the Neolithic (Agricultural) Revolution. Much of Homo Sapiens’ nutrition acquisition strategy relied on hunter-gatherer techniques before the implementation of domestication and agriculture (Ye, 2011). Estimates of past hunter-gatherer diets have been extrapolated from the modern hunter-gatherer population, known as the Kung. The Kung derive about 33% of their energy intake from animal sources and 67% from plant sources. Over half of all of their calories comes from the lipid-dense Mongongo nut, supplemented by animal foods, tubers, and some wild plants (Milton, 2007). The diet of post-agricultural revolution humans is characterized by a large percentage of calories from starches, particularly grains and tubers. Agricultural also secured a regular source of meat and dairy products for daily human consumption. This dietary shift is generally associated with an increase in sedentarism and excess of energy intake (Ye, 2011).
What sticks out most here to me? Largely plant based diets, a lot of foods that are not in the food supply (insects, worms) and the human requirement for denser energy sources (i.e. meats, dairy and/or starches- grains, tubers, legumes). I always find it interesting that what popular diets tend to exclude are these some part of these latter energy dense sources- you have vegetarians and vegans obscuring meat and other animal products, you have paleo/low carb'ers excluding a lot of the starches.
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