Catching Fire by Wrangham
Ref: Richard Wrangham (2009). Catching Fire; How Cooking Made Us Human. Basic Books.
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Summary
What made us human? This book proposes a new answer. I believe the transformative moment that gave rise to the genus Homo, one of the great transitions in the history of life, stemmed from the control of fire and the advent of cooked meals. Cooking increased the value of our food. It changed our bodies, our brains, our use of time, and our social lives. It made us into consumers of external energy and thereby created an organism with a new relationship to nature, dependent on fuel.
Cooking increases the amount of energy our bodies obtain from our food. The extra energy gave the first cooks biological advantages. They survived and reproduced better than before. Their genes spread. Their bodies responded by biologically adapting to cooked food, shaped by natural selection to take maximum advantage of the new diet. There were changes in anatomy, physiology, ecology, life history, psychology, and society.
Our evolution occurred in two major steps: first, the appearance of the habilines, and second, the appearance of Homo erectus. Meat eating and cooking account respectively for these two transitions, and therefore for their accompanying increases in brain size.
Brain Size Increases
1) Forest Apes (350-400 cc) to Australopithecines (~450 cc): Occurred between 7-5 Ma due to a dietary change from foliage to higher quality roots.
2) Australopithecines (450 cc) to habilines (612 cc): Occurred ~2.3 Ma due to meat-eating (brain size increased while body weight remained similar).
It seems likely that habilines processed their meat, slicing them into steaks, laying them on flat stones, and pounding them with logs or rocks. Even relatively crude hammering would have reduced the costs of digestion by tenderizing the meat and breaking connective tissue…Tenderizing meat would have reduced the costs of digestion by cutting the time that meat was in the stomach, and thus allowed habilines to divert energy toward their brains.
3) Habilines (612 cc) to Homo erectus (870 cc): Occurred between 1.9-1.8 Ma due to cooking or even control of fire (body size increased from the lowly 32-37 kg of habilines to a substantial 56-66 kg in Homo erectus).
4) H. erectus (870 cc) to H. heidelbergensis (1200 cc): Occurred after 800 Ka due to meat intake, and perhaps the use of animal fats.
5) H. heidelbergensis (1200 cc) to H. sapiens (1400 cc): Occurred between 300-200 Ka.
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Primates
Pan Genus
P. troglodytes (‘Chimpanzees’): Primates with a cranial capacity of ~350-400 cc.
Australopithecus (‘Woodland Apes’) Genus: Early primates approximately the size of chimpanzees; they climbed well, had ape-sized bellies, and protruding, apelike muzzles. They walked upright and can be reconstructed as having had sufficiently strong and mobile arms to be good climbers. They slept in trees and had a cranial capacity of ~450 cc. Species include A. afarensis, A. garhi, and A. Africanus.
Paranthropus (‘Robust’ Australopithecines) Genus: Evolved in Africa ~3 Ma, possibly descendants of A. afarensis or A. africanus. They flourish in some of the same dry woodlands as our human ancestors until their extinction ~1 Ma and still looked like upright-walking chimpanzees. But even more than their Australopithecus ancestors, Paranthropus relied mainly on a diet of roots and other plant storage organs. Species include P. robustus and P. boisei.
Homo (‘Human’) Genus
H. habilis (‘handy-man’) (‘Habilines’): The earliest member of the genus Homo with the same body weight of Australopithecines and a cranial capacity of 612 cc (based on the measurements of five skulls). They stood ~1-1.3 m tall and weighed similar to a chimpanzee- ~32 kg for a female and ~37 kg for a male. They had much bigger chewing teeth than in any subsequent species of the Homo genus (the surface areas of three representative chewing teeth decreased by 21% from habilines to early Homo erectus). Habilines’ larger teeth imply a bulky diet that required a lot of chewing. They walked upright, had sufficiently strong and mobile arms to be good climbers, and slept in trees.
H. erectus: (Evolved from habilines, possibly due to cooking) Primates with a cranial capacity of 950 cc by 1 Ma (their brains continued to increase in size after 1.8 Ma). The main changes in anatomy from the evolution of habilines to Homo erectus were an increase in cranial capacity (~42%), a reduction in tooth size, and an increase in energy availability. Additionally, Homo erectus had a less flared rib cage and a narrower pelvis than the australopithecines, both features indicating that they had a smaller gut. These changes support the idea that cooking was responsible for the evolution of Homo erectus. Homo erectus presumably climbed no better than modern humans do, unlike the agile habilines. This shift suggests that Homo erectus slept on the ground. The control of fire could explain why Homo erectus lost their climbing ability.
Homo heidelbergensis: (Evolved from H. erectus) A homo species with a large face, less rounded head, and cranial capacity of ~1200 cc.
Homo sapiens: (Evolved from H. heidelbergensis ~ 200 Ka) A homo species with a cranial capacity of ~1400 cc. Various modern behaviors are seen for the first time around this transition, such as the use of red ocher (presumably as a form of personal decoration), making tools out of bone, and long-distance trade.
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Intro
Man-the-Hunter (‘Meat-eating’) Hypothesis: The transition from australopithecine to human occurred from meat-eating.
~2.3 Ma: Habilines, the “missing link” between apes and humans, emerge as a new species, possibly due to meat-eating.
~1.9-1.8 Ma: Habilines evolve into Homo erectus, possibly due to cooking.
Little change has occurred in human anatomy since the time of Homo erectus ~2 Ma. Culture is the trump card that enables humans to adapt, and compared to the 2My human career, most cultural innovation has been recent.
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Ch 1 Quest for Raw-Foodists
Raw-foodists: People who eat 100% of their diets raw.
Giessen Raw Food Study: The most extensive food study; found that the more raw food women ate, the lower their BMI and the more likely they were to have partial or total amenorrhea. Among women eating totally raw diets, about 50% entirely ceased to menstruate. A further proportion, about 10%, suffered irregular menstrual cycles that left them unlikely to conceive.
The average weight loss when shifting from a cooked to a raw diet was 12 kg for women and 9.9 kg for men. Among those eating a purely raw diet (31%), the body weights of almost a third indicated chronic energy deficiency. The scientists’ conclusion was unambiguous: “a strict raw food diet cannot guarantee an adequate energy supply.”
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Ch 2 The Cook’s Body
Temporalis & Masseter: Chewing muscles.
Molars: Human chewing teeth.
Small Intestine: The main organ for digestion and nutrient absorption.
Colon: Large intestine.
The weight of our guts is estimated at about 60% of what is expected for a primate of our size: the human digestive system as a whole is much smaller than would be predicted on the basis of size relations in primates.
Our small mouths, teeth, and guts fit well with the softness, high caloric density, low fiber content, and high digestibility of cooked food. The reduction increases efficiency and saves us from wasting unnecessary metabolic costs on features whose only purpose would be to allow us to digest large amounts of high-fiber food.
Plants are a vital food because humans need large amounts of either carbohydrates (from plant foods) or fat (found in a few animal foods). Without carbohydrates or fat, people depend on protein for their energy, and excessive protein induces a form of poisoning…The maximum safe level of protein intake for humans is around 50% of total calories, the rest must come from fat, such as blubber, or carbohydrates, such as in fruits and roots.
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Ch 3 The Energy Theory of Cooking
Cooking gelatinizes starch, denatures protein, and softens everything. As a result of these and other processes, cooking substantially increases the amount of energy we obtain from our food.
Digestibility: The proportion of a food our bodies digest and absorb. If the digestibility of a particular kind of starch is 100%, the starch is a perfect food: every part of it is converted into useful food molecules. If it is 0%, the starch is completely resistant to digestion and provides no food value at all.
Digestive System (Humans): Consists of two distinct processes; 1) digestion by our own bodies, which starts in the mouth, continues in the stomach, and is mostly carried out in the small intestine; 2) digestion (fermentation) by >400 species of bacteria and protozoa in our large intestine (‘colon, large bowel’). Foods digested by our bodies (from the mouth to the small intestine) produce calories that are wholly useful to us. Foods digested by our intestinal flora yield only a fraction of their available energy to us- about half in the case of carbs such as starch, and none at all in the case of protein.
Acid is vital to digestion. Our empty stomachs are highly acidic thanks to the secretions of a billion acid-producing cells that line the stomach wall and secrete 1-2 liters of hydrochloric acid a day. Food entering the stomach buffers the acidity and causes a more neutral pH, but the stomach cells respond rapidly and secrete enough acid to return the stomach to its original low pH, < 2. This intense acidity has at least three functions: it kills bacteria that enter with the food, activates the digestive enzyme pepsin, and denatures proteins.
Ileostomy: The surgical removal of the large intestine. Patients have a bag, or stoma, where the ileum ends.
The percentage of cooked starch that has been digested by the time it reaches the end of the ileum is at least 95% in oats, wheat, potatoes, plantains, bananas, cornflakes, white bread, and the typical European or American diet (a mixture of starchy foods, dairy products, and meat). A few foods have lower digestibility: starch in home-cooked kidney beans and flaked barley has an ileal digestibility of only around 84%. Comparable measurements of the ileal digestibility of raw starch are much lower. Ileal digestibility is 71% for wheat starch, 51% for potatoes, and a measly 48% for raw starch in plantains and cooking bananas…Cooked starch yields more energy than raw.
Glycemic index (GI): A widely used nutritional measure of a food’s effect on blood sugar levels.
High-GI Foods: Include pure sugar, white bread, and potatoes, are good sources of energy after exercise, but for most people they are poor foods because they easily lead to excessive weight gain. In addition, the calories they offer tend to be “empty,” being low in protein, essential fatty acids, vitamins, and minerals.
Low-GI Foods: Include whole-grain bread, high-fiber cereals, and vegetables, reduce weight gain, improve diabetes control, and lower cholesterol.
The amino acids of chicken eggs come in about 40 proteins in almost exactly the proportions humans require. The match gives eggs a higher biological value- a measure of the rate at which the protein in food supports growth—than the protein of any other known food, even milk, meat, or soybeans.
When eggs are cooked, the proportion of protein digested averages 91-94%. Cooking increases the protein value of eggs by around 40%.
Denaturation: Occurs when the internal bonds of a protein weaken, causing the molecule to open up. As a result, the protein molecule loses its original 3D structure and therefore its natural biological function. Denaturation occurs through heat, acidity, NaCl, and drying.
The simple process of denaturation by heat (causing the protein molecule to unfold and lose its solubility in water) explains its greatly increased susceptibility to digestion.
An animal slaughtered without being stressed retains more glycogen in its muscles. After death the glycogen converts to lactic acid, which promotes denaturation and therefore a more tender meat.
Connective Tissue: Composed of a fibrous protein called collagen and a stretchy one called elastin, connective tissue wraps animal meat in three pervasive layers:
Endomysium: The innermost layer of connective tissue, which surrounds each individual muscle fiber like the skin of a sausage.
Perimysium: The middle layer where bundles of endomysium-enclosed muscle fibers lie alongside one another jointly sheathed in a larger skin.
Epimysium: The outer most layer where bundles of perimysium enclose the entire muscle. At the end of the muscle, the epimysium turns into the tendon (the tensile strength of tendons can be half that of Al).
Collagen: The main protein in connective tissue; owes its toughness to a repeating structure- three left-handed helices of protein twirl around one another to form a right-handed superhelix. The superhelixes join into fibrils, and the fibrils form fibers that assemble into a crisscross pattern. The effect is a marvel of microengineering. The extraordinary mechanical strength of collagen explains why sinews, or tendons, make excellent bowstrings and why it is the most abundant protein in vertebrates: it is the main component of skin. But collagen has an Achilles’ heel: heat turns it to jelly. Collagen shrinks when it reaches its denaturation temperature of 60-70 C and then, as the helices start to unwind, it starts melting away. Whether heated about 100 C for a short time or at lower temperatures for a longer time, the fibrils of collagen fall apart until they convert into the very antithesis of toughness: gelatin, a protein with commercial uses from Jell-O to jellied eels.
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Ch 4 When Cooking Began
Prior to half a million years ago, there is no evidence for the control of fire in Europe.
Fire-use is strongly attested at 790 Ka. In a well-dated site called Gesher Benot Ya’aqov, next to Israel’s Jordan River, hand axes and bones were first discovered in the 1930s, and in the 1990s, Naama Goren-Inbar found burnt seeds, wood, and flint. Olives, barley, and grapes were among the species of seeds found burned.
Evolutionary anthropologists Victoria Wobber and Brian Hare tested chimpanzees and other apes in the US, Germany, and Tchimpounga, a Congolese sanctuary. Across the different locations, despite different diets and living conditions, the apes responded similarly. No apes preferred any food raw. They ate sweet potatoes and apples with equal enthusiasm whether raw or cooked, but they preferred their carrots, potatoes, and meat to be cooked.
When primates eat, sensory nerves in the tongue perceive not only taste but also particle size and texture. Some of the brain cells (neurons) responsive to texture converge with taste neurons in the amygdala and orbito-frontal cortex of the brain, allowing a summed assessment of food properties. This sensory-neural system enables primates to respond instinctively to a wide range of food properties other than merely taste, including such factors as grittiness, viscosity, oiliness, and temperature.
Studies of Galapagos finches by Peter and Rosemary Grant showed that during a year when finches experienced an intense food shortage caused by an extended drought, the birds that were best able to eat large and hard seeds—those birds with the largest beaks—survived best. The selection pressure against small-beaked birds was so intense that only 15% of birds survived and the species as a whole developed measurably larger beaks within a year. Correlations in beak size between parents and offspring showed that the changes were inherited. Beak size fell again after the food supply returned to normal, but it took ~15 yrs for the genetic changes the drought had imposed to reverse.
In fewer than 8000 yrs, mainland boa constrictors that occupied new islands off Belize shifted their diets away from mammals and toward birds, spent more time in trees, became more slender, lost a previous size difference between females and males, and were reduced to a fifth of their original body weight.
Drawing from the fossil record, evolutionary biologist Stephen Jay Gould suggests that 15-20K years may be about the average time one species takes to make a complete evolutionary transition to another.
The anatomical differences between a cooking and a precooking ancestor should be at least as big as those between a chimpanzee and a gorilla.
Before 2 Ma, there is no suggestion for the control of fire. Since then there have been only three periods when our ancestors’ evolution was fast and strong enough to justify changes in the species names. They are the times that produced Homo erectus (1.8 Ma), Homo heidelbergensis (800 Ka), and Homo sapiens (200 Ka). These are therefore the only times when it is reasonable to infer that cooking could have been adopted.
In wooded areas from 4-1.5 Ma, our ancestors would have found saber-toothed cats. There was Megantereon, the size of a leopard, and Dinofelis, as big as a lion. In more open habitats there was the scimitar cat Homotherium, equally large. An extinct kind of lion and spotted hyena lived alongside our early ancestors, while modern lions and leopards have been present since at least 1.8 Ma. There were also many large animals such as elephants, rhinoceroses, and buffalo-like ungulates that could stumble unawares onto an unconscious biped.
For >2.5 My, our ancestors have been cutting meat off animal bones, and the impact was huge. A diet that included raw meat as well as plant foods pushed our forebears out of the australopithecine rut, initiated the evolution of their larger brains, and probably inspired a series of food-processing innovations. But according to the evidence carried in our bodies, it would take the invention of cooking to convert habilines into Homo erectus.
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Ch 5 Brain Foods
In the view of many evolutionary anthropologists, the pressure for intelligence comes primarily from the advantages of outwitting social competitors, whereas a major reason for species differences is how much brainpower the body can afford. For this reason, the quality of the diet has been identified as a key driver of the growth of primate brains.
Social Brain Hypothesis: Large brains have evolved because intelligence is a vital component of social life. Animals that live in groups can benefit from being clever by outwitting their rivals in competition over mates, food, allies, and status. Species with bigger brains tend to have more complex societies.
From smallest to largest brain size in primates; lemurs are as as small-brained as typical mammals followed by monkeys, then apes, and finally humans, with the biggest brains. Relative to body weight, primates with smaller guts have larger brains.
Expensive Tissue Hypothesis: Bigger brains evolved because primates that spend less energy fueling their intestines can afford to power more brain tissue; big brains are made possible by a reduction in expensive tissue.
In primates the tendency to use energy saved by smaller guts for added brain tissue is particularly strong, presumably because most primates live in groups, where extra social intelligence has big payoffs.
Basal Metabolic Rate: Our energy budget at rest; our brains use ~20% despite comprising ~2.5% of body weight.
Brains were notably bigger in late Homo erectus than in early Homo erectus, and in late Homo heidelbergensis than in early Homo heidelbergensis.
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Ch 6 How Cooking Frees Men
Group size in chimpanzees rapidly adjusts to monthly changes in the density and distribution of fruiting trees.
Sexual Division of Labor: (theorized to have been made possible by cooking) Women and men make different and complementary contributions to the household economy.
Humans devote between a fifth and a tenth as much time to chewing as do the great apes.
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Ch 7 The Married Cook
Before cooking, we ate more like chimpanzees, everyone for themselves. After the advent of cooking, we assembled around the fire and shared the labor.
Cooking takes time, so lone cooks cannot easily guard their wares from determined thieves such as hungry males without their own food. Pair-bonds solve the problem. Having a husband ensures that a woman’s gathered foods will not be taken by others; having a wife ensures the man will have an evening meal. According to this idea, cooking created a simple marriage system; or perhaps it solidified a pre-existing version of married life that could have been prompted by hunting or sexual competition. Either way, the result was a primitive protection racket in which husbands used their bonds with other men in the community to protect their wives from being robbed, and women returned the favor by preparing their husbands’ meals.
In the western desert of Australia, every large hunted animal had to be prepared in a rigidly defined fashion when it was brought to camp. The hunter’s own share of a kangaroo was the neck, head, and backbone, while his parents-in-law received a hind leg, and old men ate the tail and innards. The contrast with women’s ownership of their foods is striking. Although women forage in small groups and might help one another find good trees or digging areas, their foods belong to them. The sex difference suggests that the cultural rules that specify how women’s and men’s foods are to be shared are adapted to the society’s need to regulate competition specifically over food.
Cross-cultural evidence shows that women’s cooking for the family is a universal pattern.
A woman’s need to have her food supply protected is unique among primates and provides a sensible explanation for the sexual division of labor.
Food, it seems, routinely drives a man’s marriage decision more than the need for a sexual partner…The proposal that the human household originated in competition over food presents a challenge to conventional thinking because it holds economics as primary and sexual relations as secondary.
The idea that cooking led to our pair-bonds suggests a worldwide irony. Cooking brought huge nutritional benefits. But for women, the adoption of cooking has also led to a major increase in their vulnerability to male authority. Men were the greater beneficiaries. Cooking freed women’s time and fed their children, but it also trapped women into a newly subservient role enforced by male-dominated culture. Cooking created and perpetuated a novel system of male cultural superiority.
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Ch 8 The Cook’s Journey
Thrifty-Gene Hypothesis: Humans are physiologically adapted to an erratic food supply. Because the environments of our hunter-gatherer ancestors were highly seasonal, we are physiologically adapted to periods of feast and famine. Accordingly, ancestral humans supposedly digested and stored energy in their bodies with exceptional efficiency. According to the hypothesis, this efficiency was a useful adaptation when starvation was a consistent threat but is responsible for obesity and diabetes in many modern environments.
Cooking Hypothesis: During human evolution, the use of cooked food would have left us better protected from food shortages than the great apes are, or than our noncooking ancestors were. It implies that humans easily become obese as a result of eating exceptionally high-energy, calorie-dense food, rather than from ancient adaptation to seasonality.
As physiologist Peter Wheeler has long argued, this may be why humans are “naked apes”: a reduction in hair would have allowed Homo erectus to avoid becoming overheated on the hot savanna. But Homo erectus could have lost their hair only if they had an alternative system for maintaining body heat at night. Fire offers that system. Once our ancestors controlled fire, they could keep warm even when they were inactive. The benefit would have been high: by losing their hair, humans would have been better able to travel long distances during hot periods, when most animals are inactive. They could then run for long distances in pursuit of prey or to reach carcasses quickly. By allowing body hair to be lost, the control of fire allowed extended periods of running to evolve, and made humans better able to hunt or steal meat from other predators.
By the period between 3-2 Ma, several genera and many species of australopithecines had already occupied the African woodlands for perhaps three million years. At that time, the only known species of australopithecines were Australopithecus afarensis, A. garhi, and A. africanus, and then even they disappeared. Climate change appears responsible for the extinction of australopithecine species. Africa began getting drier ~3 Ma, making the woodlands a harsher and less productive place to live. Desertification would have reduced the wetlands where australopithecines would have found underwater roots, such as cattails and water lilies, and they would have found fewer fruits and seeds. The species of Australopithecus had to adapt their diet or go extinct. Two lines survived. One adapted by intensifying its reliance on the underground foods that had provided the backup diet of less preferred foods for australopithecines in times of food scarcity. Their descendants rapidly developed enormous jaws and chewing teeth, and are recognized in the naming of a new genus, Paranthropus, or the “robust” australopithecines. Paranthropus emerged ~3 Ma, possibly descendants of Australopithecus afarensis or A. africanus. They flourished in some of the same dry woodlands as our human ancestors until a million years ago and still looked like upright-walking chimpanzees. But even more than their Australopithecus ancestors, Paranthropus relied mainly on a diet of roots and other plant storage organs. The other line of descendants led to humans, and it began with meat eating. Australopithecines must always have been interested in eating meat when they found fresh kills, just as chimpanzees and almost every other primate are today. They would therefore have readily pirated carcasses from any predator they were willing to confront, such as cheetahs or jackals, both of which had close relatives present in Africa by 2.5 Ma.
By at least 2.6 Ma, some groups were definitely getting meat from carcasses that previously only big carnivores would have eaten. Over the next few hundred thousand years, impact notches and cut marks on animal bones caused by stone tools attest to habilines spending long enough in the danger zones to be able to slice the meat off dead animals, from turtles to elephants. The result was a new and immensely beneficial food source.
When pyrites, a common ore containing iron and sulfur, are hit against flint, the result is a set of such excellent sparks that pyrites and flint are standard components of fire-making kits.
During the tens of thousands of generations between the origin of habilines (at least 2.3 Ma) and Homo erectus (at least 1.8 Ma), from time to time the sparks resulting from habilines’ pounding rocks could have accidentally produced small fires in adjacent brush…Or maybe they obtained fire from trees that burned slowly after being struck by lightning; a eucalyptus tree can smolder for eight months.
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Epilogue The Well-Informed Cook
With the ready availability of such products as HFCS, cheap palm oil, and intensely milled flour, measured daily energy intake in the US rose by almost 200 calories between 1977 and 1995.
In a study on rats, those that ate a softened diet gained an extra 30% fat despite having no extra calories in the food…We become fat from eating food that is easy to digest.
Atwater System: A system developed by Wilbur Atwater for estimating the energy values in foods. Atwater’s admirable aim was to ensure that poor people could use their limited resources to get enough to eat. He set out to discover how many calories different foods provided. Atwater’s general factors: proteins and carbs yield ~4 kcal/gram, lipids yield 9 kcal/gram.
Proteins: Yields ~ 4 kcal/gram. 16% of the weight of an average protein is N.
Fats: Yields ~ 9 kcal/gram with energy value obtained from dissolution of fats in either. Fat (‘lipid’- lipids include both fats, which are solid at room temperatures, and oils, which are liquid) content
Carbohydrates: Yields ~4 kcal/gram with energy value obtained by burning food completely and then comparing the organic to inorganic matter; the weight of the carbs was what was left when the weights of the fat, protein, and mineral ash had been subtracted from the total weight of the original food item.
Digestibility: Obtained by analyzing the feces of people eating precisely measured diets; rarely > 10%.
Alcohol: Yields ~ 7 kcal/gram.
One failure of the Atwater convention does not recognize that digestion is a costly process. When we eat, our metabolic rate rises, the maximum increase averaging 25%...Protein costs more to digest than carbohydrates, while fat has the lowest digestive cost of all macronutrients…A second failure of the Atwater system is that it assumes that the proportion of food digested is always the same, regardless of whether the food is in liquid or solid form, part of a high-fiber or low-fiber diet, or raw or cooked.
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Misc Quotes
The word lady is derived from the Old English hlaefdige, meaning “bread kneader,” whereas lord comes from hlaefweard , or “bread keeper.”
The estimated total number of cases due to the top 20 harmful bacteria, including Staphylococcus, Clostridium, Campylobacter, Listeria, Vibrio, Bacillus, and Escherichia coli (E. coli), is in the tens of millions per year.
The USDA’s National Nutrient Database for Standard Reference and Robert McCance and Elsie Widdowson’s The Composition of Foods are the principal sources for public understanding of the nutrient data for thousands of foods in the United States and the United Kingdom, respectively. They provide the data for our food labels.
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Terminology
Biological Value: A measure of the rate at which the protein in food supports growth.
Foie gras: The liver of French geese that have been cruelly force-fed to make them especially fat. The fresh liver is soaked in milk, water, or port, marinated in Armagnac, port, or Madeira, seasoned, and finally baked.
Granules: Dense packages of stored glucose that contain the starch inside plant cells.
Maillard Compounds: Complex molecules such as heterocyclic amines and acrylamide, that form from a process that begins with the union of sugars and amino acids, particularly lysine. Maillard compounds occur naturally in our bodies and increase in frequency with age. They occur at low concentration in natural foods but under the influence of heat their concentration becomes much higher than what is found in nature, whether in smoke (from fires or cigarettes) or cooked items. Their presence is easily recognized in the brown colors found in pork crackling or bread crust. Maillard compounds cause mutations in bacteria and are suspected of leading to some human cancers.
Masticate: Chew (food).
Pectic Polysaccharides: Glue plants cells together.
Rumen: The first stomach of a ruminant, which receives food or cud from the esophagus.
Wagyu Cattle: One of the most expensive cattle breeds in the world because their meat is exceptionally tender, and no effort is spared to make it so. The animals are raised on a diet that includes beer and grain, and their muscles are regularly massaged with sake, the Japanese rice wine. The fat in the meat is claimed to melt at room temperature.
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Chronology
1972: Japanese soldier Shoichi Yokoi returns to Japan from Guam after 30 yrs living in the jungle in the belief WWII was still being fought (Catching Fire by Wrangham).
1960: Jonathan Leakey, the 20-yo son of paleontologist Louis Leakey and archaeologist Mary Leakey, discovers Habilines, the missing link between apes and humans, in the form of a jaw, skull, and hand in Tanzania’s Olduvai Gorge (Catching Fire by Wrangham).
1704-1709: Robinson Crusoe; after quarrelling with the captain of his ship and rashly demanding to be put ashore, Alexander Selkirk is castaway for 4 yrs on the island of Más a Tierra in the Juan Fernandez Islands, 670 km West of Chile in the Pacific Ocean. He had a bible, a musket with a pound of powder, some math instruments, a hatchet, a knife, and a few carpenters’ tools (Catching Fire by Wrangham).
10 Ka: Pottery is invented (Catching Fire by Wrangham).
15 Ka: Wolves begin their evolution into dogs after first being drawn to human villages in search of food refuse (Catching Fire by Wrangham).
120 Ka: Homo sapiens are heating materials in natural containers. Evidence shows that people made a glue from ancient birch tar, which they used to haft stone points on to spears (Catching Fire by Wrangham).
~200 Ka: Homo sapiens (1400 cc cranial capacity) evolve from Homo heidelbergensis (1200 cc cranial capacity) (Catching Fire by Wrangham).
~300-200 Ka: Homo sapiens begin evolving from Homo heidelbergensis (Catching Fire by Wrangham).
427-364 Ka: Europe’s interglacial period (Catching Fire by Wrangham).
500- 400 Ka: Ice covers all of Britain (Catching Fire by Wrangham).
790 Ka: Proto-humans are purportedly using fire at a well-dated site called Gesher Benot Ya’aqov next to Israel’s Jordan River (Catching Fire by Wrangham).
800-600 Ka: Homo heidelbergensis (1200 cc cranial capacity) evolves from Homo erectus (870 cc cranial capacity) in Africa, possibly due to an increase in meat-intake, the consumption of animal fats, and the control of fire. The main changes in anatomy from Homo erectus to Homo heidelbergensis were an increase in cranial capacity (~30%), a higher forehead, and a flatter face (Catching Fire by Wrangham).
1 Ma: Homo erectus cranial capacity is ~ 950 cc (Catching Fire by Wrangham).
1.4 Ma: Homo erectus is first recorded in Spain (Catching Fire by Wrangham).
1.44 Ma: The most recent evidence of a habiline (specimen #KNM-ER 42703) (Catching Fire by Wrangham).
1.6 Ma: Homo erectus is first recorded in SE Asia (Catching Fire by Wrangham).
1.7 Ma: Homo erectus is first recorded in Western Asia (Catching Fire by Wrangham).
1.78 Ma: The most definitive evidence of Homo erectus (specimen #KNM-ER 3733) (Catching Fire by Wrangham).
1.8 Ma: Evolution of modern lions and leopards (Catching Fire by Wrangham).
~1.9-1.8 Ma: Homo erectus (870 cc cranial capacity) evolves from habilines (612 cc cranial capacity), possibly due to cooking or even control of fire. The main changes in anatomy from the evolution of habilines to Homo erectus were an increase in cranial capacity (~42%), a smaller gut, a reduction in tooth size, an increase in body mass (32-37 kg to 56-66 kg) and an increase in energy availability, possibly supporting the idea that cooking was responsible for the evolution of Homo erectus (Catching Fire by Wrangham).
>2 Ma: There is no suggestion for the control of fire in any proto-human group (Catching Fire by Wrangham).
~2.3 Ma: Habilines (450 cc cranial capacity) evolve from australopithecines (612 cc), emerging as a new species and the “missing link” between apes and humans; possibly due to meat-eating. Habilines processed their meat, slicing them into steaks and pounding/tenderizing them with logs or rocks. In this transition, brain size increased while body weight remained similar (Catching Fire by Wrangham).
~2.5 Ma: Proto-humans pass on the MYH16 gene, causing our jaws to become uniquely weak (Catching Fire by Wrangham).
~3-1 Ma: Life of Paranthropus (‘Robust’ Australopithecines) in Africa, possibly descendants of Australopithecus afarensis or A. africanus. They flourish in some of the same dry woodlands as our human ancestors until ~1 Ma (Catching Fire by Wrangham).
~3-2 Ma: Australopithecus afarensis, A. garhi, and A. africanus are the only known species of australopithecines in Africa (Catching Fire by Wrangham).
~3 Ma: Africa begins getting drier with desertification taking place and making the woodlands a harsher environment (Catching Fire by Wrangham).
~7-5 Ma: Australopithecines (~450 cc cranial capacity) evolve from forest apes (~350-400 cc cranial capacity) possible due to a dietary change from foliage to higher quality roots (Catching Fire by Wrangham).
7-5 Ma: Humans last common ancestor with chimpanzees (Catching Fire by Wrangham).
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