NEW YORK — It’s not what you expect to discuss when you sit down with a playwright, especially one who’s opening on Broadway in a few days. But it’s really hard not to talk about food with Nicky Silver.

Because food, like motherhood and family, just keeps coming up in conversation, as it does in Silver’s many plays.

Not that food is at the center of “The Lyons,” Silver’s latest work and the first to move to the Great White Way, after a successful off-Broadway run. But the lines about food get such laughs — not to spoil them, but there’s one about an Entenmann’s coffee ring, and another about those sugarcoated Jordan almonds — that it seems clear it’s an integral part of things.

Both lines are delivered by Linda Lavin, who plays Rita Lyons — a mother, of course. Talk about your related themes: motherhood and food.

Certainly food sounds like an integral part of Silver’s life, too. A self-described former chubby kid, he’s clearly not forgotten that feeling, and it’s fascinating to hear how he transformed himself a decade ago, through a diet that consisted of bacon, deli meat, cheese, and burgers, all lathered with mayonnaise (except the burgers.)

Really? Yuck, we say, as we sit with him in a favorite diner near his Upper West Side apartment, a week before opening night. Don’t knock it, he counters.

“I lost 70 pounds (32 kilograms) in the first five months,” says Silver, 51. On the down side, he did develop diverticulitis, “which is as painful as childbirth.” Wait, how do you know how childbirth feels? “My friend told me.”

But as “The Lyons” was gathering steam at off-Broadway’s Vineyard Theatre last year, Silver, filled with nervous energy, let loose. “I ate like I was tunneling out of a chocolate prison,” he says, sounding suspiciously like a witty character in one of his plays. “I jumped two pants sizes.”

This was not, however, the nervousness of a fledgling playwright. Silver has been writing plays for three decades, with his most famous ones — before “The Lyons” — coming in the ’90s, including “Pterodactyls” and “Raised in Captivity,” both nominated for Drama Desk awards.

There are dozens of Silver plays, and amazingly, at least a dozen don’t even exist anymore. That’s right — there are no copies, Silver says, and he doesn’t seem too bothered about it.

“We didn’t have computers back then,” he explains. “It’s fine. In fact, I’m sure the theater community is breathing a huge sigh of relief.”

Today, Silver isn’t eating — he’s nervously drinking Diet Coke and fingering the cigarette that he’ll smoke once our interview ends. He’s been attending every preview at the Cort Theatre. Everything feels bigger.

“The laughs feel bigger,” he says. “There’s a murmur at the end of the play — that feels bigger too.”

But Silver himself? “I don’t feel different or more successful,” he says. “I have no more confidence than I did last year.”

Silver grew up in the Philadelphia area, and graduated from New York University’s Tisch School of the Arts. One of his early breaks was a production of his 1991 play “Fat Men in Skirts” at the Woolly Mammoth Theater in Washington, D.C. The Washington Post wrote: “Silver never met a pain he couldn’t laugh at.”

Which is very true of “The Lyons,” a play about pain that is also very, very funny.

Lavin’s Rita is a creation like no other, a Jewish mother, but not the kind you may be thinking of, the kind who thinks her kids are the cat’s meow and subsumes her needs to those of her family. She tells her daughter she thinks her little boy might be retarded — just moderately. “It’s not a criticism,” she says.

She’s annoyed that her husband isn’t enthusiastically hopping on board with the redecoration plans for the living room. He won’t be seeing it, of course — he’s in the hospital, dying of cancer.

“This cancer eating away at you has put you in a terrible mood,” Rita observes drily.

You could say dysfunctional families, featuring complicated mothers, are Silver’s bread and butter. Well, if he ate carbs.

“People say that — it’s not entirely accurate,” he says. “But I’ll own it. The parent-child relationship is our most basic one. The great plays of our time are family plays. Think ‘Death of a Salesman.’ Everything from ‘Long Day’s Journey ‘Into Night’ to ‘August: Osage County.'”

The mother Lavin plays, though, is special, and that’s because Lavin plays her, he says: “The only reason we’re going to Broadway, and the reason you and I are sitting here, is because Linda Lavin decided to do this play.”

That’s especially relevant because Lavin had a few big opportunities last fall when not one but two productions she was in — “Follies” in Washington and “Other Desert Cities” at Lincoln Center — moved to Broadway. She opted for Silver’s play instead.

“That’s one of the reasons I am so glad we’re moving to Broadway,” Silver says, “so it doesn’t feel like we snookered her.”

Her presence has attracted some high-profile guests to previews. “The other night, Billy Crystal and Neil Simon came backstage,” he says. Silver was so nervous, he says, that “I remember almost none of it.”

As the opening draws near, Silver seems to be suffering from more intense bouts of nerves. He comes each night to previews, but stands across the street as people enter, smoking, avoiding the crowd.

He also gives in to a complex set of superstitions. They involve eating the same thing every day, wearing lucky neckties, keeping the same objects in his pockets. He also gives more to homeless people. “The homeless in the neighborhood know when I am opening a play,” he quips. “They get bills instead of coins.”

Silver doesn’t want to count his chickens, though the reception at previews has been quite enthusiastic. But even if all goes well, there’s one thing, one elusive thing, that would be better.

“I’d rather be handsome,” he says. “Maybe that should be on my tombstone.” But actually, he notes, he’s long known what he wants his tombstone to read:

“Here Lies Nicky Silver — Thin at Last.”