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Raw Food Diet and Your Brain

Eating only raw food may do more harm that good for brain healthIf a raw food diet appeals to you, think twice. New research from Brazil suggests that the capacities of human brains evolved far beyond those of gorillas and chimps because our early ancestors learned to cook food. Investigators at the Federal University of Rio de Janeiro determined that human brains have an average of 86 billion neurons, while gorillas have 33 billion of these brain cells and chimps only 28 billion. They also found that the more neurons a brain has, the more calories are needed to support its function. If humans ate only raw foods, the researchers calculated, we would have to eat for more than nine hours straight in order to get enough calories to sustain the energy requirements of our bigger brains. The investigators also report that the human brain consumes 20 percent of body energy when resting compared to nine percent in other primates. Researchers elsewhere have suggested that human brains began to expand once our ancient ancestors learned how to cook food over fire. And lab studies have shown that animals grow up bigger and faster when they eat cooked, rather than raw meat. The study from Brazil was published online on October 29, 2012 in the Proceedings of the National Academy of Sciences.

My take? These are interesting evolutionary findings, and I find them quite sensible. The main argument in favor of eating this way is that cooking destroys vital enzymes in foods. In fact, these enzymes play no role in human nutrition, because stomach acid destroys them as efficiently as cooking. In addition, some nutrients found in vegetables are actually less bioavailable when you eat these foods raw. Another disadvantage of eating foods raw is that many of the natural toxins in edible roots, seeds, stems and leaves can be destroyed by cooking them in water.

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Reader Comments (17)

"If humans ate only raw foods, the researchers calculated, we would have to eat for more than nine hours straight in order to get enough calories to sustain the energy requirements of our bigger brains."

By what magic does cooking anything increase its calories?

January 28, 2013 | Unregistered CommenterAmy

Amy: cooking increases density, you'll be able to eat and digest more food. Compare eating 300 grams of spinach raw vs cooked and then being able to eat something else with that. (On a sidenote: juicing also increases density and allows for more caloric intake). Also, cooking with grease, adding cream, sauces etc definitely increases calories.

January 28, 2013 | Unregistered CommenterCatty

@Amy: Cooking doesn't increase calories, but it expands the range of foods available to eat by killing germs that would otherwise make certain foods very dangerous to eat.

January 28, 2013 | Unregistered CommenterHansa

Well, I hope everybody reading this can think for themselves. I find no validation in any of it.
Eat for 9 hours straight? I eat 3 normal meals, to get my 2700 calories a day, if I need 3500, I will do that ;-) How would I get more if I cooked it?
This information has no root in reality, which shows that people prosper on living foods, like nature intended.

January 28, 2013 | Unregistered CommenterHilde

Seeing as how humans did not "evolve" from Gorillas and Chimpanzee's, I don't understand how a statistical, comparative assessment of brain capacity can be made- more so, how the cooking of foods or the caloric density therein would be in any way relevant to sustaining "brain power".. I've been on a raw foods diet for 6 months now, and I've never felt more alive in my life, let alone creative and motivated to do things.. Also, cooking may increase caloric density- or whatever- but at the expense of killing vital nutrients in things such as veggies. And the body needs more nutrients than calories last time I checked :)

January 28, 2013 | Unregistered CommenterTroy

If it was about calories then eating MacDonald's burgers and chocolate bars would make us intelligent. It is about the quality of food we eat. I don't think America's health problem is about not eating enough 'calories'. Take a look around and that is quite obvious.

January 28, 2013 | Unregistered CommenterCarol

I'd like to see who paid for this research to be done. Unfortunately, that info isn't available that I've been able to find. I suspect there may be a conflict of interest, although none were cited by the authors:

January 28, 2013 | Unregistered CommenterMatt L

I'm a huge fan of Dr Weil, but this article causes me to take pause.

"If humans ate only raw foods, the researchers calculated, we would have to eat for more than nine hours straight in order to get enough calories to sustain the energy requirements of our bigger brains."

LOL. This quote alone makes me think these "researchers" are retarded. Seriously. I don't even need to explain.

I've long been aware of raw food diet, but have never heard that stomach acids destroy enzymes. If that is indeed the case, then a huge premise of the raw food argument is indeed moot, it seems.

However, you cannot ignore the nutrient benefits of raw fruits and vegetables, which Dr Weil and just about every other authority has touched on countless times before.

In my opinion, the conclusion of this "research" should be that our brains got larger when we began expanding our diet (eating a larger variety of foods as cooking allows), instead of simply not eating exclusively raw anymore.

January 29, 2013 | Unregistered CommenterJesse

Just more propaganda people can use against me for eating raw and not wanting to eat their meat dairy white rice etc. Sick of having to defend my food choices! Have these researchers never heard of blenders and other kitchen appliances?

January 29, 2013 | Unregistered CommenterJane

Although raw food has more nutrients than cooked, other research indicates many people cannot absorb all those nutrients through the digestive process. Studies show humans absorb more nutrients (not calories) from eating cooked foods rather than raw because even though there are fewer nutrients, they are absorbed in a higher percentage. The best way to get nutrients from raw food is by juicing or preserving via lacto-fermentation.

January 29, 2013 | Unregistered CommenterAmy G

Blah blah blah, just so much supposition and no facts, which may never fully be known. What we do know is that today people are able to heal from disease and thrive on a raw food diet...certainly without eating for nine

January 29, 2013 | Unregistered CommenterHugh

If you really think about it, we animals don't "evolve" all that quickly. How long ago do you think it was that we started cooking our foods? Ok, early caveman. That is really only a drop in the bucket in the sense of evolution. Just because we were "smart" enough to cook foods, doesn't mean that our bodies evolved enough to recognize it. I'm not at all into a total raw food diet (more because of taste) but I can completely see the value in it.

If you are talking about raw meat, all the other animals on this planet eat their meat raw. The reason we cook our meats is because of the long delay before consuming. Early caveman might have died if they didn't cook their Mammoth after day 2 due to bacteria load. Unless they killed their animals and ate them all on the spot, they found that cooking prevented illness and death.

So really, our evolution is just convenience. Allowing us to keep our food longer than really is healthy. Now we have refrigeration which helps prolong the decay process even longer.

Bottom line, our bodies were designed (like every BODY/ANIMAL on this planet) to eat food in its original form. Cooking denatures (changes) the molecular "look" of our food, some speculate it doesn't exactly know what it is after it is cooked.

I think our bodies have adapted to survive IN SPITE OF us eating our food cooked. But I think they would do better with raw, original form, foods.

I'm no scientist, this is just theory based loosely on fact... ;)

January 30, 2013 | Unregistered CommenterJuice Diva

The calories in raw foods are not as digestible as the calories in cooked foods. This is in part because cooking denatures the proteins and breaks down the fiber, making the calories more digestible and therefore bioavailable. In essence, this means cooked foods have more calories--or embedded energy--than raw foods.

This is why raw diets work so well for weight loss, and why some people experience digestive trouble and nutrient deficiencies despite maintaining a balanced raw diet.

February 1, 2013 | Unregistered CommenterDawn

Thank you Dawn and Amy for your fact-based, scientific-oriented responses. It's always refreshing to read such comments. What I would add is that everybody's body is different and works differently. The important thing is to find your own balance, what makes YOU feel good in your body and mind. I was a vegetarian for more than 10 years and by the end of it I felt tired, without energy, and I was always hungry and couldn't sleep properly. As soon as I started to eat meat again, I actually felt I had more energy, my body was recuperating faster, and I slept like a baby. But I totally respect that a lot of my friends still are vegetarian, and they feel great in their body and mind...
Dr Weil, I have a question: is it true that the different blood types require different diets? According to what I've heard, the time in our evolution when the different blood types appeared would determine if we are more confortable with raw food, meat, or harvested grains... but I don't know if it is a scientific theory. Thanks!

February 4, 2013 | Unregistered CommenterSamuel Savard

I think eating raw food is not a good idea. In fact, when the food is steamed or made into soup, the moisture based cooking prevents food from browning and forming toxic compounds. It’s all about how well you manage your diet so that you stay healthy and fit. Great post!!

April 5, 2013 | Unregistered CommenterRoy Ramirez
This "study" is basically garbage. The real scientific fact is that humans have been eating our food raw longer than we have been cooking it. And I seriously doubt that the main factor for our larger brains is because we learned to cook food.We had a lot more going on then that. No one knows what it was like back then, and don't let scientists fool you into thinking that they know; because they don't. They are making a lot of assumptions, with very little real data. The human and plant fossil record is by no means complete. And all this talk about not being able to digest raw fruits and vegetables is pure BS. Remember what they used to say about vegetarianism when it first started gaining popularity. Scientists always think they are right until they are proven wrong. Remember this, western "scientists" used to think that the sun revolved around the earth while many "primitive" people knew things about the solar system and stars that they didn't know. Scientists and scientific "studies" have been wrong many many times about a lot of things.
July 10, 2013 | Unregistered Commenterkojo
It's the reason why I don't completely go raw. I also add some cooked meat on my diet, but I make sure that it is only enough to provide the calories that my body needs. You should also know about moderation even if you are on a raw diet. Try looking at a raw food blog and you will know that it is not really a good idea to go raw for the rest of your life.
March 24, 2014 | Unregistered CommenterSara Allen

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