Wednesday, February 9, 2011

We Are Not Cows

Except maybe these people.

At some point, you've probably come across the claim that vegetarian diets are better for you because "meat humans can't digest meat -- it just rots in your colon and causes colon cancer." Humans, the argument goes, are natural herbivores.

But science says otherwise. Even in studies dating back almost a hundred years, it's been consistently shown that meat doesn't rot in your colon. Beans, grains and vegetables do.
It turns out that pepsin, trypsin, chymotrypsin, and our other proteases do a fine job of breaking down meat protein, and bile salts and lipase do a fine job of breaking down animal fat. In other words, meat is digested by enzymes produced by our own bodies. The primary reason we need our gut bacteria is to digest the sugars, starches, and fiber -- found in grains, beans, and vegetables -- that our digestive enzymes can’t break down.
The digestion of sugars, starches and fiber also make you fart more. (Between you and me, since going Paleo over a year ago, I've noticed a drastic reduction in my personal methane emission levels. Who says I'm not doing my part for the environment?)

Humans aren't herbivores. We're omnivores -- though we're "primarily carnivorous":
[W]e have a limited ability to digest some plant matter (starches and disaccharides) in order to get through bad times, but we cannot extract meaningful amounts of energy from the cellulose that forms the majority of edible plant matter, as true herbivores can. We can only eat fruits, nuts, tubers, and seeds (which we call ‘grains’ and ‘beans’) -- and seeds are only edible to us after laborious grinding, soaking, and cooking, because unlike the birds and rodents adapted to eat them, they’re poisonous to humans in their natural state.
You can demonstrate the purpose and limits of human digestion with a simple experiment: eat a steak with some whole corn kernels, and see what comes out the other end. It won’t be the steak.
In fact, meat-eating made us human.

Fun activity: Google "meat rots in your colon" and count the number of articles arguing this point were written by PETA. Incidentally, my favorite PETA moment is when it produced a comic book for children, telling them that their non-vegetarian mommies are in fact evil murderers:
How would you feel if someone took away your kitten or puppy, stomped on their head, and ripped their skin off their bodies? It would make you feel sad, wouldn’t it? Why would someone be so mean? But there are truly terrible people who cause our furry friends to die that way every day. And guess what? One of those terrible people is your mommy.

(Source: Gnolls)