November 21, 2009

Catching Fire by Richard Wrangham

Catching Fire by Richard Wrangham (Prof. of Biological Anthropology @ Harvard)
How cooking made us Human

[Some good info which we seldom notice or aware]

Now a days we need fire for wherever we are. Survival manuals tells us that if we are lost in the wild, one of our first actions should be to make a fire. In addition to warmth and light, fire gives us hot food, safe water, dry clothes, protection from dangerous animals, a signal to friends, and even a sense of inner comfort. As per Darwin, "probably the greatest (discovery), excepting language, ever made by man".

Cooked food does many familiar things. It makes our food safer, creates rich and delicious tastes and reduces spoilage. Heating can allow us to open, cut, or mash, tough foods. But none of these advantages is as important as a little-appreciated aspect: 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. We humans are the cooking apes, the creatures of the flame.

The most extensive raw-food study is Giessen Raw Food study. The average weight loss when shifting from a cooked to a raw diets was 26.5 pounds. Among those eating a purely raw diet, the body weights of almost a third indicated chronic energy deficiency. The scientist conclusion was unambiguous: "a strict raw food diet cannot guarantee an adequate energy supply". However among people who eat cooked diets, there is no difference in body weight between vegetarians and meat eaters: when our food is cooked we get as many calories from a vegetarian diet as from a typical American meat-rich diet. It is only when eating raw that we suffer poor weight pain. In the Giessen study, the more raw food that women ate, the lower their BMI and more likely they were to have partial or total amenorrhea. Healthy women on cooked food diets rarely fail to menstruate, whether or not they are vegetarian.

In 'How too Do the Raw food Diet with Joy for Awesome Health and Success, the author Christopher mentions that raw-diet reduces sexual appetite. Reduced reproductive function means that in our evolutionary past, raw-foodists would have been much less successful than the habit of eating cooked food. Since cooking predictably destroys many toxins, we may have evolved a relatively sensitive palate. U.S Centers of Disease Control and Prevention state that at least forty thousand cases of food posioning by 'Salmonella' alone are reported annually in US. The best prevention is to cook meat, fish and eggs beyond 140 Fahrenheit (60 degrees) and not to eat foods containing unpasteurized milk or eggs.

Delicious has a different or another meaning- It means high energy, because what people like are foods with low levels of indigestible fiber and high levels of soluble carbohydrates, such as sugars. Even carrots are better quality that typical wild tropical fruit, because they are less fiber and fewer toxic compounds.

Raw-foodiests are very enthusiastic about the health benefits as described in books with such titles as 'Self healing Power' and ' How to tap into the great power within you'. they report a sense of well-being, better physical functioning, less bodily pain, more vitality and improved emotional and social performance. There are claims of reduction in rheumatoid arthritis and fibromyalgia symptoms, less dental erosion and improved antioxidant intake.

Through the changes of raw-food to cooked food, our body changed accordingly. We have small mouth to eat big foods than a cooked food (compared to Chimpanzees jaw /mouth). In humans the surface area of the stomach is less than one-third the size expected for a typical mammal r our body weight and smaller than in 97% of other primates. The high caloric density of cooked food suggests that our stomachs can afford to be small. 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.

Any protein that was undigested by the time it reached the ileum was metabolically useless to the person who ate it because in the large intensive bacteria and protozoa digest the food proteins entirely for their own benefits.

Plants are vital food because humans need large amounts of either carbohydrates(from plat 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. Symptoms of protein poisoning include toxic levels of ammonia in the blood , damage to the liver and kidneys, dehydration ,loss of appetite and ultimately death.

Hunters carry high caloric density, such as avocados, olives or walnuts. The US department of Agriculture's national Nutrient Database for Standard Reference and Robert McCance and Elsie Widdowson's The Composition of foods are the principle sources for public understanding of the nutrient data for thousands of foods in US and UK respectively.

Our digestive system consists of two distinct process. the first is digestion by our own bodies, which starts in the mouth, continues in stomach and is mostly carried out in the small intestine. the second is digestion or strictly fragmentation, by 400 or more species of bacteria and protozoa in our large intestine also known as the colon or large bowl. Foods that are digested by our bodies (from mouth to small intestine) produce calories that are wholly useful to us. But those that are digested by our intestinal flora yield only a fraction of their available energy to us - about half in the case of carbohydrates such as starch and none at all in the case of protein.

The % 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 typical Eu & US diet (a mixture of starch foods, diary products and meat). A few foods have lower digestibility: starch in home-cooked kidney beans and flaked barely has an ideal digestibility of only around 84%. Gelatinization happens whenever starch is cooked whether in the baking of bread, the gelling of pie fillings, the production of pasta, the fabrication of starch-based snack foods, the thickening of sauces or we can surmise, the toss if a wild root into fire. The more starch is gelatinized, the more easily enzymes can reach it and therefore the more completely it is digested. Thus cooked starch yields more energy than raw. Glycemic Index is a widely used nutritional measure of food's effect on blood sugar levels. Low GI foods such as whole grain foods, high fiber cereals and vegetables reduce weight gain, improve diabetes control and lower cholesterol. Cooking consistently increases the GU of starchy foods.

Body builders believe that eggs should be taken raw(Charles Atlas, Arnold Schwarzenegger, Silvester Stallion - all takes egg in raw to have big muscles as they proclaim). the amino acids of chicken eggs come in about 40 proteins in almost exactly the proportions human require. This 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.

However Belgium scientists study says, cooking of eggs increased the protein value of eggs by around 40%. Researches concluded that simple process of denationalization by heat (causing the proteins molecules to unfold and lose its solubility in water) explained its greatly increased susceptibility to digestion.

heat is only one of several factors that promote de-naturalization. Three others are acidity, sodium chloride and drying all of which humans use in different ways. Acid is vital in the ordinary process of digestion. The acidity has at least three functions: it kills bacteria that enter with the foods, activates teh digestive enzyme pepsin and denatures proteins. Animal protein that has been salted and dried, such as fish, is likewise denatured and thereby made more digestible.

The most expensive sandwich ($148) is a mixture of fermented sourdough bread, Wagyu beef, etc. Wagyu beef explains the high price. Wagyu cattle are one of the most expensive 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 Wagyu beef claimed to melt at room temperature.

As per Scientist R.A. Lawrie, 'Of all the attributes of eating quality, texture and tenderness are presently rated the most important by average consumer and appear to be sought at the expense of flavor and color". As per the cooking historian Michael Symons, cooking's main role has always been to soften food. "hurrying over our meals, as we do, we should fare badly if all the grinding and subdividing of human food had to be accomplished by human teeth"..

Above 60-70 degrees of temperature (140-158 Fahrenheit) , slow cooking in water can sometimes continue to increase the tenderness. If heated heavily, heated muscle fibers tend to get tougher and drier. The cumulative effect of cooking meat are therefore complex. Bad cooking can render meat hard to chew, but good cooking tenderize every kind of meat. In the book, "Joy of Cooking' recommends grinding top sirloin or scraping it with the back of a knife until only the fibers of connective tissue remain.

Why a regular sandwich have lettuce in them. Eating meat with leaves, provides greater taste. (Chimpanzees always eat meat with leaves; if fresh leaves not available, it will go for dried leaves).

Food contains three major macro-nutrients - protein, fat and carbohydrates.

Cooked food helps us to digest fast and gets us more calories. This idea is used in farming of animals (in Salmon farming, Salmons gets cooked fish and also cow/ox gets cooked food so that they become larger and heavier in size)

Book refereed in this book: ' The Joy Of cooking" , "The US department of Agriculture's national Nutrient Database for Standard Reference" and Robert McCance and Elsie Widdowson's "The Composition of foods".

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