Monday, December 15, 2008

Advent 2008 December 15

Well, it looks like I am too far behind this year, and don't expect to catch up. I ought to have picked something simpler - or done a better preliminary design. And I did get side-tracked, as usual, and went too deep too quickly.

But I will try to keep going, at least for those of you who may already be interested.

Let us get back to the central idea. Food is necessary for life. This means that food brings something into us which we need, and since we know from experience that we need different foods, and that trying to live from one single food is probably not healthy, we must have various kinds of needs - that is, there are different purposes to our food. I mean, apart from the obvious one of satisfying our hunger.

What are those purposes?

In order to answer that question, we can come at it from two directions: (1) What is food, and what does it contain? (2) What are our bodies made of, and what is it they "use up" or require in order to stay alive?

Just for a change, let's start with the second way.

This human body is a material structure. It is built out of various components. In order to grow it needs more of those components. In order to do things, it needs energy. These two needs account for most of what we eat - but there are a few other things besides that we need and some of them are perhaps a little startling.

1. We need the main building blocks: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, sodium, chlorine, potassium, calcium, and a handful of others. These have to come in a form that the body can handle - we cannot eat coal or diamonds, or get our nitrogen from the air - and some (like sodium, phosphorus, and chlorine) are deadly poisons in their pure forms.
2. We need fuel - something which can supply energy. We're not a fireplace or an internal combustion engine (like a car engine) so the fuel is not "burnt" in the dramatic way a fire burns wood or oil - but the fuel is truly burned in the sense of being combined with oxygen, because it produces the usual result of fires: carbon dioxide (that's what we breathe out).
3. We need certain things - not simple components like sulfur, but actual compounds - to come in a directly useful form - some things which our bodies cannot make for themselves. This must sound rather odd, but it is a simple fact. One gets sick if one does not eat certain things in the right proportion.
4. We also need material to help in getting rid of the material we eat that we cannot use. This sounds even more odd, but then except for water and salt and sugar, there aren't any other materials that we can actually consume that we can use in their pure forms! And since we have to eat things in their natural form (like fruits or vegetables), or in a form that we process according to a huge variety of traditional methods (we use the term "cooking" as a general verb for this), or we may unintentionally eat things we don't really need, like dust, bugs, dirt on baked potatoes, burnt corners of toast, and so forth - but also stuff we cannot really avoid, like certain pigments in fruits - all these we need to get rid of, and so we need something which (like the water in our blood) can serve as a "transport". (We're getting to some delicate matters here, I know.)
5. There is something else, which is rather on the mystic side, but I don't mean in a religious or supernatural sense, like a sacrament. Not yet, anyway. But there is another need which arises from our humanity which does not arise from any biochemical reaction. I will talk about this later, and we can argue about it then.

How do our meals satisfy these needs? Let us go through them, and give the simple answers, and perhaps in coming days I will write more.

1. Building blocks: The primary answer is protein This supplies all of the basic CHONPS needs of the elements - well, all but the P, but since we almost always eat complete cells, we get DNA and RNA as well as protein, and that has P (but no S).
2. Fuel: There are three answers: fats, starches, and sugars. Some people say "carbohydrates" for starches and sugars. All of these are "burned" - that is combined with oxygen - to produce energy to run the body and do things like move and talk and think.
3. Other special things: There are several components for living which our bodies cannot make, such as vitamins and various other biochemicals. We must get them from something whih has already made them - and we must be sure that we do not destroy them when we cook or store them.
4. Waste: The often-heard term "fiber" is the answer - but we also need water in any of its forms, like beer or wine or milk.
5. The mystic thing: that need we shall hear more about in the future. For now, all I will say is that there is a difference between (say) a plant in the sun, or a dog eating, or a car's gas tank being filled - and any human meal, even the simplest.

And we shall proceed again later, as time may permit.


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