Month: September 2009

A few weeks ago, raw food was abuzz in blogland. I gave it a try to help my digestion, but that way of eating didn’t work for me. Now that it’s fall I’ve noticed less and less talk about raw food, and more and more posts about oatmeal, baked squash, and delicious apples. It’s propitious that Bobby alerted me to this article yesterday… Did Cooking Give Humans An Evolutionary Edge? – a transcript of an NPR talk from Science Friday. It has to do with the differences between humans and other primates (like this gorilla that lives in the San Francisco zoo)…

I thought the transcript was incredibly interesting. You can also listen to the program (it’s just under 30 minutes). If you don’t have time to read or listen though, I’ll summarize here…

• It’s an interview with Dr. Richard Wrangham, a primatologist (someone who studies primates = humans, apes, monkeys, and prosimians) who wrote Catching Fire: How Cooking Made Us Human.
• Dr. Wrangham proposes that cooking has actually been a key aspect of evolution and our bodies have changed over the years due to the fact that we can cook our food. It’s given us a huge evolutionary advantage because we have more time to use our brains instead of foraging and chewing all day long. (This is called biocultural evolution, when you evolve along with the tools/methods of your culture.)
• Apes show either a preference for cooked food over raw food, or they are neutral… they never prefer raw to cooked food.
• A human’s digestive system is 2/3rds the size of an ape’s (if you adjust for the size of the ape versus the size of the human) and we have small teeth and small mouths – not ideal for lots of chewing.
• We’ve adapted to a “high quality” diet. (High quality meaning mostly cooked and easy to digest… not talking about the processed, industrial “food” crap that most people live on.) Cooking is what increased the “quality” of our diet.
• We don’t have to eat large amounts of food and we don’t have to retain and ferment food for many many hours to digest it.
• The changes to our digestive system happened about 1.8 million years ago.
• Cooking our food increases the proportion of nutrients and energy that we’re able to digest. While a cooked carrot may technically have the same number of calories as a raw one, we are able to access more of the calories from the cooked one. Another example – when you cook an egg and eat it, you can digest about 94% of the protein. A raw egg? You digest about 60%. That’s a big discrepancy.
• Why does cooking make things easier to digest? For protein, the process is called denaturation. The protein cells are kind of like a big ball of yarn; cooking unwinds the yarn so it’s easier to digest. One way to denature something is to put it in acid. So our stomach acid can do some of this, but cooking makes it that much easier for our bodies to digest protein. A similar process happens with starch – chains of sugars open up during cooking so that they are more readily available to absorb.
• Humans are one of the only species that typically does not thrive on a raw diet… about half of women following a raw diet stop menstruating and most people lose weight (due to an energy shortage = significant calorie/nutrient deficiency).
• Now this doesn’t mean that a raw diet can’t be beneficial – a lot of people are eating too much currently, so a raw diet may help them reduce the amount of food they eat (because it’s so limiting) so they can maintain their weight and feel better. A lot of the benefits that come from a raw diet are due to cutting out processed foods and chemicals. Many people have undiagnosed food allergies (gluten, wheat, dairy, etc…) and since those foods aren’t common in a high raw diet, people will feel better since they’re not eating them anymore.
• Again, eating more raw food is not necessarily bad or unhealthy, but you should not follow a high raw diet. If you live in a place where food is scarce, you should especially *not* follow a raw diet… if you live in the US or another developed country, incorporating more raw foods into your diet is a fabulous idea if it will help you eat less and eat fewer processed, industrial foods.
• Many people think that following a raw food diet is the most “natural” way to live… not true. We have evolved away from eating raw food. And one of the major reasons that we’ve been able to advance so far in terms of knowledge and technology is due to the fact that we are NOT like other primates – we don’t have to eat all day to get enough food, giving us time to use our gargantuan brains.

I’m learning about some similar concepts in my anthropology class. There is the idea of biocultural evolution, which basically says that our culture (using tools, cooking food, etc…) has a large influence on our evolution. The invention of tools allowed us to evolve away from huge teeth. The cultural idea of wearing clothes might be the reason that we aren’t covered in hair. And maybe cooking is responsible for changing our digestive system, our mouths, and our teeth.

What works best for me is a fairly natural diet (no processed foods) with a little bit of raw food. I am influenced by macrobiotics (completely cooked, nearly vegan but with fish, and very Japanese). I’m also influenced by the paleo diet (limited grains and carbs, lots of animal fat and protein, lots of veggies – mostly all cooked). When I eat fruit it’s usually raw I do snack on raw veggies sometimes. I love salad (obviously, again) but I don’t eat salad every day unless it’s the summer. I love my oatmeal, oat bran, baked and steamed squash, and many other cooked foods, especially in the cooler months.

What works for you? What do you think of the ideas that this guy is proposing?