Thursday, July 10, 2008

Processing power

The nice thing about writing on eating habits is that the English language is relatively unimaginative towards food: a raw diet is one in which you eat nothing but raw or only partially-cooked foods (heating food above 120 F is not allowed, under the theory that higher temperatures "destroy" enzymes within the food that allow you to better digest and use it. Macrobiotics is much the same, in that the belief is that processing a food in any way beyond cooking (what you would normally do at home) also tampers with the "essential" vitamins and somehow destroys the nutritive value of the food.

There are, as per usual, truths and untruths to this belief. On the one hand, it is known that some vitamins, vitamin C and folate amongst them, are inactivated by heat, and that many proteins are denatured when exposed to high temperatures.

Let's address the protein issue a bit further: proteins are essentially like a ball of tangled yarn. The analogy of dumbbells, joined end-to-end, which I used earlier to describe them, is still true, but rather than one long thread, they snake back and forth, in and out--like a ball of yarn. If you apply heat to them, they may unwind, and look like a long thin thread, but--and this is critical--the order with which they are arranged remains the same (if you have access to a protein lab, you can try this with serum, 8 M urea, and a circular dichroism spectrometer). But it is how the protein is coiled that gives it the specific properties, and furthermore, whether it remains coiled depends on things other than merely heat--the acidity of the environment, for instance, or the presence of salts and sugars. If you consider how food is eaten--seasoned, flavored to taste, chewed, swallowed--even the most raw diet is going to end up denaturing something.

The issue with "killing" the vitamins, is a more valid reason to eat raw food (though, as we shall see, it does not mean that you should switch your oven for a dehydrator). Vitamins, especially the more complex ones, are sensitive to heat, and many of the fatty acids that are touted today as being good for you are also highly susceptible to oxygenation, which turns them rancid.

What is oft forgotten about a raw diet, in the midst of the frenzy about feeling good and being healthy, is that the only reason such things are possible is because our food supply is reasonably safe--and that presupposes that random spinach and tomato contaminations are indeed random and not a sign that our food safety program requires a massive overhaul. There is some speculation as to whether cooking "evolved"--a hominid stumbling across a charred carcass and finding out that burned flesh is actually not that bad--or was invented, but either way, the point remains that humans have been cooking their food for at least 10,000 years, when the first civilizations arose. You don't stick with a fad that's not useful, and killing dangerous germs on your food is infinitely useful.

However, there is one thing that these diets get right: processed food isn't good for you. Making my own lentil soup allows me to tweak the flavors so that I get to taste what I like. Opening a can of lentil soup, on the other hand, means that I have bought into what a chef ten-thousand miles away, has decided I should like, and has added salt, sugar, and flavorings, accordingly. Processed foods are often stripped of their fiber, flavored with "things", preserved with "other things", and even colored and gussied up to look, if you think about it, nothing like food. I'm not really opposed to chemicals in our food--some of them are inevitable, after all--but it's probably better for you to eat less of them. It's the addition of fats, sugars, and salt, and the removal of fiber and vitamins that makes processed food unhealthy.

Or maybe we just need healthier palettes. A raw diet, like any other diet, is what you make of it. If you do your research, and follow good food safety rules, then odds are you won't make the New England Journal of Medicine under "Bizarre cases". I once considered going on a raw diet, and went so far as to purchase a cookbook (using my Borders Cash Back rewards). It was after a failed attempt at making nut milk that I decided that maybe raw is a bit more difficult than it seemed.

No comments: