As an aside, ever notice all the soy 'meats' they make for vegetarians and vegans? You'd think their wanting that would tell them something...
2 comments:
markm
said...
Williamson does rather overstate his case. Humans are designed to be omnivores, not carnivores - because the closer you can get to being able to eat _anything_ you can find, the better you can survive a dry season or a winter in the short-term, and survive ice ages in the long term. Other animals often specialized in a particular food source, but humans survived as generalists. If there's fruit, we'll eat it. If a readily available and high-calorie plant is poisonous, we'll cook the poison out of it (taro root, for example). Another example is beer - barley is pest-resistant because it is poisonous, and ages of selective breeding hasn't entirely removed the poison, but fermentation does. OTOH, if the best local source of food is mammoths or whales, we'll learn to catch them and we'll eat them.
I do like the debunking of the argument that our teeth aren't fit for carnivores. That's usually made by someone who has never looked at the dentition of a horse or an iguana. Iguanas bite limbs off of trees; they don't have a killing bite, but they can mangle your arm pretty good. I'll get to horses in a while - for now, I'll just note that their teeth are poorly arranged for killing, but they can cut and grind much better than any carnivore. Carnivores have big incisors and canine teeth for killing, but generally the rest of their mouth is just more pointy teeth for holding and killing prey. They don't need to chew their food much, because any chunk of meat that will fit down your gullet will digest in a few hours. Humans evolved their current much-reduced teeth after they invented better ways of killing prey animals. They eventually also invented mortars to grind grain, etc., but it wasn't recent enough for us to have evolved out of molars.
Contra Williamson, many wild plants are not poisonous - although the nonpoisonous ones are generally protected in some other way - thorns, woody fibers to make them hard to chew, etc. Grasses are an extreme example; they actually dissolve silica and take it up through their root, to deposit tiny sand grains in their leaves and stalks. Also, the leaves and stalks are remarkably lacking in digestible substance - it's mostly cellulose, and no multicellular animal can produce enzymes to break down these huge molecules. The seeds (grain) have to contain starch, oil, and some protein, so they would seem a better choice, but in wild grasses the seeds are tiny and hidden in tough husks. If you're much bigger than a rabbit, it's going to be difficult to harvest and thresh enough wild grain for a meal.
Horses evolved to eat grass. They have very powerful incisors in the front to snip off bits of grass, and huge molars in the back to grind it fine. These teeth grow all their life, to compensate for wear from the sand particles in the grass. Then, since animals can't digest the cellulose, their digestive system mixes the grindings with liquids and bacteria, and waits for fermentation to break down the cellulose. Horses and ungulates need huge abdomens to handle that job. Or look at apes; they feed on much higher quality plants than a horse, but they still have a large protruding abdomen to hold a very long intestinal tract. A man that has a similarly-proportioned belly is either starving to death or grossly and unhealthily overweight.
It's not actually necessary to have a hundred pounds of intestines to digest plants, but the alternative isn't pretty. Rabbits have continually growing teeth, large enough to give you a nasty bite (in proportion to their size). They can chew grass like a horse, but it passes through too fast to ferment. So they eat their own shit and run it through again. I'd rather not emulate them.
Anyway, primitive people ate plants and animals, changing their diet and their abode with the seasons. They learned to do considerable processing to render the plants softer and more edible, but half the time they ate animals raw, right where they caught them. Plants probably were most of their calories; you can't judge by modern hunter-gatherers, because these are not primitives, but rather highly sophisticated users of the scant resources in parts of the world so unattractive that no civilized people will go to the trouble of driving them out and claiming the land themselves. But plants could NOT have provided all of their protein and vitamins.
There is one way grain, nuts, and beans are better than meat; just by drying them, they can keep for a long time. In an area that has a winter or a dry season severe enough to sharply cut back on the fauna, you can't survive on hunting alone, and you can't keep meat for the whole time. The earliest men just migrated to a better area for the bad part of the year, but eventually those refuges became overcrowded. The survival came to depend on collecting and keeping plants, which encouraged permanent homes, which led to agriculture, which led to unhealthily starchy and low-meat diets. One sure sign of conversion from hunting-gathering to agriculture is that the skeletons average several inches shorter, and show more signs of injuries, disease, and overwork. But there would be a lot more people surviving in an agricultural society, even if barely, so the hunter-gatherers were badly outnumbered...
2 comments:
Williamson does rather overstate his case. Humans are designed to be omnivores, not carnivores - because the closer you can get to being able to eat _anything_ you can find, the better you can survive a dry season or a winter in the short-term, and survive ice ages in the long term. Other animals often specialized in a particular food source, but humans survived as generalists. If there's fruit, we'll eat it. If a readily available and high-calorie plant is poisonous, we'll cook the poison out of it (taro root, for example). Another example is beer - barley is pest-resistant because it is poisonous, and ages of selective breeding hasn't entirely removed the poison, but fermentation does. OTOH, if the best local source of food is mammoths or whales, we'll learn to catch them and we'll eat them.
I do like the debunking of the argument that our teeth aren't fit for carnivores. That's usually made by someone who has never looked at the dentition of a horse or an iguana. Iguanas bite limbs off of trees; they don't have a killing bite, but they can mangle your arm pretty good. I'll get to horses in a while - for now, I'll just note that their teeth are poorly arranged for killing, but they can cut and grind much better than any carnivore. Carnivores have big incisors and canine teeth for killing, but generally the rest of their mouth is just more pointy teeth for holding and killing prey. They don't need to chew their food much, because any chunk of meat that will fit down your gullet will digest in a few hours. Humans evolved their current much-reduced teeth after they invented better ways of killing prey animals. They eventually also invented mortars to grind grain, etc., but it wasn't recent enough for us to have evolved out of molars.
Contra Williamson, many wild plants are not poisonous - although the nonpoisonous ones are generally protected in some other way - thorns, woody fibers to make them hard to chew, etc. Grasses are an extreme example; they actually dissolve silica and take it up through their root, to deposit tiny sand grains in their leaves and stalks. Also, the leaves and stalks are remarkably lacking in digestible substance - it's mostly cellulose, and no multicellular animal can produce enzymes to break down these huge molecules. The seeds (grain) have to contain starch, oil, and some protein, so they would seem a better choice, but in wild grasses the seeds are tiny and hidden in tough husks. If you're much bigger than a rabbit, it's going to be difficult to harvest and thresh enough wild grain for a meal.
Horses evolved to eat grass. They have very powerful incisors in the front to snip off bits of grass, and huge molars in the back to grind it fine. These teeth grow all their life, to compensate for wear from the sand particles in the grass. Then, since animals can't digest the cellulose, their digestive system mixes the grindings with liquids and bacteria, and waits for fermentation to break down the cellulose. Horses and ungulates need huge abdomens to handle that job. Or look at apes; they feed on much higher quality plants than a horse, but they still have a large protruding abdomen to hold a very long intestinal tract. A man that has a similarly-proportioned belly is either starving to death or grossly and unhealthily overweight.
It's not actually necessary to have a hundred pounds of intestines to digest plants, but the alternative isn't pretty. Rabbits have continually growing teeth, large enough to give you a nasty bite (in proportion to their size). They can chew grass like a horse, but it passes through too fast to ferment. So they eat their own shit and run it through again. I'd rather not emulate them.
Anyway, primitive people ate plants and animals, changing their diet and their abode with the seasons. They learned to do considerable processing to render the plants softer and more edible, but half the time they ate animals raw, right where they caught them. Plants probably were most of their calories; you can't judge by modern hunter-gatherers, because these are not primitives, but rather highly sophisticated users of the scant resources in parts of the world so unattractive that no civilized people will go to the trouble of driving them out and claiming the land themselves. But plants could NOT have provided all of their protein and vitamins.
There is one way grain, nuts, and beans are better than meat; just by drying them, they can keep for a long time. In an area that has a winter or a dry season severe enough to sharply cut back on the fauna, you can't survive on hunting alone, and you can't keep meat for the whole time. The earliest men just migrated to a better area for the bad part of the year, but eventually those refuges became overcrowded. The survival came to depend on collecting and keeping plants, which encouraged permanent homes, which led to agriculture, which led to unhealthily starchy and low-meat diets. One sure sign of conversion from hunting-gathering to agriculture is that the skeletons average several inches shorter, and show more signs of injuries, disease, and overwork. But there would be a lot more people surviving in an agricultural society, even if barely, so the hunter-gatherers were badly outnumbered...
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