Barry Louis Polisar got started in his present occupation by pure coincidence. He was learning how to play the guitar and became a vegetarian, so he wrote a song about his dietary blues entitled "I Eat Kids."

"So it's goodybye liver.Goodbye roast beef. Hello Tommy, Michael and Debbie. I won't eat chicken and I won't eat cows. I don't eat animals.I eat children now."

Polisar, who was 19 years old at the time, played his veggie song in a coffeehouse at Prince George's Community College. An elementary school teacher in the audience asked him if he'd like to play for her class. He said yes, thus beginning his successful career as a composer and singer of unusual children's songs.

Polisar now is 25. He has written and recorded more than 80 songs, which he has distributed himself to about 350 record stores and about 13,000 public libraries across the country. He is his own agent and, as he puts it, his own "record uncompany."

Polisar gives live performances about 10 times per week in schools, recreation centers, libraries and museums in the metropolitan area. He said he earns a comfortable living, substantial enough to pay the rent on a spacious loft apartment in outer Silver Spring which he designed and renovated himself.

The titles of Polisar's songs help explain his popularily with the younger set. "My Brother Thinks He's a Banana," "I Don't Brush My Teeth and I Never Comb My Hair," "I Got a Teacher, She's So Mean" and "Shut Up In the Library" bear a not-so-mute testimony to a child's perception of the grown-up world.

Polisar believes his modest success up to now derives from his refusal to "treat kids in a lollipop way."

"I've been called a songster for children liberation," Polisar said. "That's a pigeonhole way to say it but I try to get people to laugh at themselves. I write about naughty kids and mean teachers because I think it's wrong to pretend those things don't exist. It's better to bring them out in the open and let them be laughed at."

This approach, Polisar believes, is superior to the attitudes expressed in most songs for children, which he describes as being too moralistic.

"Most (children's songs) are goody-goody," Polisar said. "Even the songs by the 'Sesame Street' people, who have made some real strides, are really scary . . . It's still adults telling kids how to act, with a tinge of a moral, telling kids how to feel."

Polisar said that he gets a lot of his material from watching children's reactions to his performance. Not all of his songs have started out as children's songs, however, as in the cast of "I Eat Kids" or the quasi-romantic "I Need You Like a Doughnut Needs a Hole." But, as an intense, ambitious and jittery young man, he sees limitations in his present subject matter.

"The ideas don't come as frequently as they used to," Polisar said. "I wrote three songs about teachers. What Else can I do with that? . . . I do and don't want to do this forever. When the bookings stop coming in and I can't live off it anymore, I'll stop. But there's a mushrooming effect. One booking produces a few others.

The typical performance begins with Polisar singing in his expressive but somewhat raspy voice a few of his satirical songs about the relationships between brothers and sisters, parents and kids, teachers and students. He then starts a sing-along, teaching the audience his songs and at the same time helping ensure they will be repeated and, at best, purchased in record form.

Some of his more notable performances have included a week at the Kennedy Center two years ago and concerts at Wolf Trap in the past three years. He is now traveling around the state of Virginia under a program administered by the Virginia Museum of Fine Arts, and plans concerts in Pennsylvania and possibly Connecticut during the summer.

But beyond the life of singing unusual songs for children, Polisar is unsure of what the future holds for him. When it comes to the subject of marriage and maybe some children of his own, Polisar maintains a characteristic attitude.

"I think children in general should be placed in boxes and shipped off to a foreign country," he joked. "I'd like to have some, enough to do the vacuuming and basic maintenance around the house."