COMMITMENTS : Party of One : Want a taste of the single life? Try tuna, jalapenos, cereal and Spam.

I’m just your basic single chick. My married friends suspect this means sex-packed nights and cereal dinners. But by the looks of Jerry Seinfeld’s TV kitchen, I’m not the only one who eats Shredded Wheat for supper.

And nobody thinks Jerry’s a lazy slob, right? We are simply among a silent majority of people who eat way differently when alone.

When we’re with company, we feel compelled to eat meals as if we’re dressing up. All the food must form an ensemble--main course, accessorized by salad and bread. Don’t clash with the side dishes! All must end with dessert and espresso. When was the last time you made yourself a cake and a pot of coffee after dinner?

The story is different when dining is Nancy, party of one.

One recent night I got home from the gym about 8 and found myself with a barren refrigerator. But my totally a la carte dinner turned out well, I thought: marinated artichoke hearts and sun-dried tomatoes from the jar, yogurt and an apple. Dirty dish count: one spoon. Nothing like that kind of satisfaction.

“Oh, right,” my friend Tim said the next morning. “Like any of that kind of food would be in a guy’s refrigerator. . . . We usually have stuff that has a long shelf life or stuff that in and of itself wouldn’t be a food item, but could be added to other food items. And, of course, beer. “

I can see inside his Amana now, I told him: jars of salsa and green olives stuffed with pearl onions and Knott’s Berry Farm gift-package jam, circa 1985, with a bag of potatoes that are growing roots.

“Right on the olives. Sub in jalapenos for salsa, and I threw out the jam after the sugar crystallized around the lid. But I have carrots with root hair longer than yours,” he corrected.

This sounds familiar. I’ve had ex-boyfriends who substituted water or orange juice for milk on their Rice Krispies rather than run to the store.

The most recent case of this occurred earlier this month on vacation in the alleged capital of fine food, France. My boyfriend opened the refrigerator in our Loire Valley apartment and realized we were out of milk. “You know,” he said, “it’s too bad you turned in that food column already, because I’m about to eat a bowl of Frosties with yogurt on top.”

(Imagine the dinner party at which you ate only what kids would subsist on if allowed: Lucky Charms, Popsicles, Twinkies, bologna slices and Kool-Aid. Then we could chase each other around the yard with squirt guns.)

The other day I tested my premise by asking via office E-mail, “What do you eat when you’re alone?” I knew within minutes I was onto something. I got even more revelations after my confessions of scooping pesto sauce, cold, with bread sticks out of the jar for dinner.

“Ditto tuna,” said a friend. “Or anything handy dunked manually into mayonnaise or salad dressing bottles. I cannot buy my favorite cereals because I eat them out of the box--in one night. I have to buy second or third choices. Bran is good. You don’t eat bran out of the box.”

Some people wanted clarification--such as what category of solo food I meant. “When I’m home alone watching TV?” asked one guy I’ll call George to protect any future love life. “Or what I like to cook? Or buy at restaurants?”

Any of the above, I said.

“Hey,” he said, “it got so bad at my place last week that I sat with the peanut butter jar and forked it into my mouth. I was too lazy to go out and buy something, the cupboards were bare but, hey, the peanut butter was there.

“Don’t forget ambience. You need this,” George added. “You see, guys when they eat certain foods pay respect to it. With a steak, I actually may sit at a table. In clothes. It’s a ritual. With junk food, it’s grubby drawers, one foot hooked over the arm of the chair.”

In a confessional tone, my editor friend Jim admitted that recently he had gone by himself to Hof’s Hut and had nothing else for dinner but a piece of strawberry pie fit for a heifer.

Sorry, Jim, but that would constitute small canned potatoes for a person coming from my family. On the rare occasions when my father would cook for himself, his idea of chow was an appetizer of canned Vienna sausages (is there such a thing as uncanned?) and a main course of the following fry-pan mixture: canned pork and beans, canned corned beef hash and, when it was available, Spam. Anything leftover and of questionable expiration date in the refrigerator would be tossed in too.

As he gets older, his taste is improving and he’s cut down on the labor. Now, he eats Popsicles and ice cream all day.