Sometimes after I've given a speech, someone asks how, by being a columnist, I have made a difference. I double up with false modesty and declare that I seek no influence and that, given the complexity of the world, I could never hope to make a difference. Now, however, I can. I have invented the low-calorie egg cream.

The words "egg cream" might call for an explanation. I know that because I once mentioned the drink in a column and was questioned by an editor of unimpeachable American-Gothic credentials. I changed the reference to "root beer," a wonderful drink in its own right but not -- I tell you -- an egg cream. That very day I heard the writer, Avery Corman, being interviewed on the radio about his latest book. The interviewer said just one thing in the book stumped him: "What's an egg cream?"

I will tell him. An egg cream is a little gift from the gods. It is what the Greeks were referring to when they made such a fuss about wine (things got mangled in translation). It is, quite simply, heaven in a glass. In other words, it's chocolate syrup, soda water and a little milk.

It is also fattening. This was not a problem for me when I was a kid and addicted to egg creams. They cost a dime and I had at least five of them a day. You could get an egg cream anywhere -- a candy store, a drug store -- I used to make them at home. I was so addicted that even when the know-nothing dermatologist told me they cause pimples, I drank them anyway. Given a choice between clear skin, popularity with girls, romance, sex . . . and . . . egg creams, I chose the last.

But alas, it has been years since I had one. Even though there is no egg in an egg cream, there is still chocolate syrup and milk. That's a lot of calories. Maybe 312,000. Just to think of an egg cream is worth maybe 126 calories and to say the word is 546. I turned to diet root beer instead. It was my version of methadone.

Then some time ago, Bob Greene, a fellow columnist and, you can see from his pictures, a guy with a bit of a weight problem, discovered Canfield's diet fudge drink. He wrote about it in his column, and I, like lots of others, tried it. Delicious. For two calories, you got a terrific chocolate drink. God, how I envied Greene. Here was a columnist who had actually made a difference.

What Greene started, I have finished. One night as I was about to down a Canfield's, my eye stopped on a container of (2 percent) milk. The light bulb of genius flashed. I reached for the Canfield's. I reached for the milk. I poured a little of the milk into a tall glass. I added the Canfield's. I watched that head of foam rise. With shaking hands, I raised the glass to my lips. Oh, boy! An egg cream. You cannot imagine my joy. I had one and then another. I made my wife taste one. My son, too. I experimented some more. A little more milk. A little less milk. Finally, I had the right proportions. Here they are: put some milk into a glass and add some Canfield's.

I concede that the new Cohencream (patent pending) is not without calories. By actual count there are precisely 32 of them -- more or less. Two come from the Canfield's and 30 or so from the 2 percent milk. (Nonfat milk would not have enough body for a good Cohencream.) For calories, this is really nothing.

It is not every day that you can recapture your youth with a mere drink. But my egg creams of old have brought a new bounce to my walk. I feel like playing stickball in the street, stoop ball on the stoop, (where else?) and a sip brings the Dodgers back to Brooklyn. Everything would be perfect, but in the interest of full disclosure, I must admit one fly in my new ointment.

I've broken out.