There are, as I write this, only 23 more eating days until Christmas.

We are, therefore, at the height of the season during which all the cherishable perishables of the culinary world are harvested into the most reliable storage facility in the world: the Average American Body.

For at least three more weeks we will munch mightily in an attempt to provide our own farm support program. Indeed, if last year's quota is to be met, we shall have to graze our way into 1982.

The results of all this are wellknown. At no other moment in our annual history will so many people gain so much weight in so little time. With so many mixed feelings. Taught that food is love, but thin is lovable, most of us will end up this holiday season bulging with other people's affection and our own self-hate.

Well, I am a veteran of many a binge-and-bust holiday season. But this year I have come upon a new solution to the age-old question of how to eat your way from Thanksgiving to New Year's without getting fat.

To give credit where it is due, the solution I am about to describe was originated by my uncle, who still retains the copyright and will receive half the royalties from our upcoming best-seller.

It begins with this simple assumption: contrary to what we have been taught, the Christmas-seasoned and stuffed Americans aren't really too fat at all. We are just too short for our current weight.

Take me, for instance. I left the Thanksgiving table at the perfect weight for someone who is 5 feet 10 inches tall. I am actually underweight for someone 6 feet tall and positively anorexic for someone who is 6 feet 4.

The only problem is that at the moment I am 5 feet 8.

You could say that I am 10 pounds too heavy. But you could also say that I am 2 inches too short.

Let me give you another example. I have a friend who weighs 125 pounds. Is she fat or thin? Only her height chart knows for sure. The point is (I'm sure you get it by now) that millions of Americans will enter 1982 feeling wretched about their fat, and trying desperately to lose it.

But, as my uncle points out in his path-breaking new work, the real problem isn't weight control, it's that we haven't a grip on the height control.

The beauty, the elegant simplicity, of his plan now comes into play. Americans should forget about the horizontal and start thinking vertical, stop thinking pounds and start thinking inches. For every 5 pounds gained, all we have to do is grow one inch.

Frankly I don't know why no one thought of this before. After all, this is how adolescents deal with their weight. The pudgy 5-foot 12-year-old invariably stretches into the lanky 6-foot 16-year-old. If they can manage it, the pimply faced wretches, so can their elders.

This is not just another impossible dream. There is even a model. According to national statistics, the average American is already growing at the rate of three-quarter inches every 25 years. All we need to do is speed things up a bit.

Under this new program, we will be able to indulge our Christmas gluttony without worrying about such mundane things as zippers. (Hems, however, will be a bit of a problem.) Instead of entering the New Year wider, we will enter it higher. (Ceilings may also be a bit of a problem.)

For the details of how to accomplish this feat, I am afraid you will have to await publication date of the work we have entitled "Upward Bound: How to Achieve the Perfect Height for Your Weight."

But I warn you that there are a few remaining kikds in our brilliant plan. My uncle, for example, keeps growing and shrinking the same three inches every December.