Thanksgiving is America's only holiday dedicated to food. Ours has been a marvelously fertile land. So over the years the national ritual of giving thanks for such agricultral bounty has been intertwined with a joyful celebration at which we consciously over-eat. It's not just the turkey that is "stuffed" on Thanksgiving Day. While Thanksgiving comes but once a year and might therefore be considered exempt from the critiques of what and how Americans eat, it is the very spirit of Thanksgiving that makes it stand out. At no other meal is so much attention focused on what is on the table. As Marian Burros illustrates in present our Thanksgiving Menu on page F2, progressive diet and health professionals are not trying to sweep the table bare. The image of a hollow-cheeked candidate for sainthood eating from a large plate containing only a few straws of raw vegetable is as inaccurate as the out-of-date assumption that anyone who prefers a vegetable diet to one oriented to meat is a "kook" or "hippie." What is being advocated is that Americans eat less and channel their food choices away from products and recipes rich in fats, sugar, salt and cholesterol. Thanksgiving dinner represents some of the positive aspects of the diet to which Americans should aspire. Traditionally care in preparation, variety and taste all are emphasized in the family Thanksgiving dinner. Careful cooking of a range of foods that taste good for any meal will go a long way toward making a revised diet palatable, and can also serve to stimulate the cook or cooks. Thanksgiving dinner may be the most important meal of the year, but others can be just as satisfying.