UNION TOWNSHIP, N.J. – For the folks at the Clinton Station Diner, second place hurts, though not as much as the process of eating a 15-pound hamburger.

For about three months, the New Jersey diner a mile west of downtown Clinton proudly served what it billed as the largest burger in the country. They call it Zeus, a 12.5-pound cheeseburger approximately the weight of a 6-month-old human. A notice printed on the paper place mats challenges customers to finish a Zeus in three hours for a free meal. Those who don’t order one often gather around a replica Zeus near the entrance and snap pictures.

On Tuesday, the owner of Clinton Station Diner, Michael Zambas, got an urgent call from his brother. A pub outside Pittsburgh, Denny’s Beer Barrel – which at one point claimed the burger record – announced the birth of the Belly Buster, a 15-pound burger made with 10.5 pounds of beef.

Suddenly bereft of its record, Zeus seemed like any old mountain of meat.

“We’re never going to give this up,” a good-humored Mr. Zambas said yesterday from his spacious diner, which has an exterior resembling a train station and looks out over Route 78. “We’re going to make it happen. We’ll give them a little time to savor the glory.”

Mr. Zambas was coy about his next move in what has become an endless cycle of sirloin.

What The New York Sun can say is that, about a week after the diner plays host to a national hamburger-eating contest next Monday, Mr. Zambas and his team of chefs plan to unveil a burger of unknown mass. It’s tentatively called Mega-Zeus.

“We definitely have the capability of doing bigger and better things,” the burger baron boasted.

In its current incarnation, it takes three people and 40 minutes to make one Zeus.

When a customer orders one, the head chef, Pete Karavoulias, rips open a plastic bag of raw 80% lean beef and dumps the stuff into a shiny mixing bowl. Folded into the mound are seven large raw eggs and a bag of breadcrumbs, to hold everything together. Mr. Karavoulias kneads the mass with his hands for several minutes before adding globs of olive oil.

Meanwhile, the hamburger roll, about the size of a loaf of challah bread, is toasting inside a pizza oven in the basement bakery. The “bun” itself, with its dense consistency, weighs more than 4 pounds.

Mr. Karavoulias flattens the meat mixture on a cookie sheet and inserts it into a convection oven for 15 minutes of searing. Two men – Mr. Karavoulias and a saucier, Armando Garcia – use two spatulas to lift the now-mud-brown meat off the cookie sheet and dump it on a flame grill. The meat spreads out over about two-thirds of the grill.

Toppings include 12 slices of American cheese, one Spanish onion, half a head of iceberg lettuce, and two beefsteak tomatoes. That vertical parade brought the total weight of yesterday’s burger to 14.5 pounds.

A knife with a 16-inch blade is used to cut the burger into six chunks, typically consumed with a knife and fork.

The burger is about 30 times the size of a McDonald’s quarter-pounder with cheese, which the fast-food chain says has 30 grams of fat and 530 calories – and presumably less egg and olive oil.

The Zeus, it must be conceded, is only a tiny fraction of the size of the heaviest hamburger ever made, a distinction held by the town of Seymour, Wis., which cooked up an 8,266-pound hamburger in 2001.

Mr. Zambas says the Clinton Station Diner has made about 90 Zeuses, averaging one a day, since introducing the burger in February to mark the restaurant’s first anniversary.

They cost $29.95 without cheese and toppings, $34 for the whole package. Not only is Mr. Zambas waiting for a customer to finish one of the burgers, he has yet to see any mere mortal come close.

A month ago, a man named John, who weighed what Mr. Zambas estimated to be 250 pounds, strode into the diner and said: “I’m going to go for the burger.”

According to Mr. Zambas, John flipped his place mat over and wrote down his strategy. He instructed himself to drink lots of water, and to condense the dough before it entered his stomach so it would take up less space.

He also would eat the burger in parts – bun, then patty. The man managed to complete half the burger – said to be the most courageous performance to date.

Mr. Zambas told another story of how a teacher brought four kids into the restaurant two weeks ago and ordered up a Zeus. The group left with a doggy bag, and the man returned the following week with seven kids for another round of Zeus. They again left with a doggy bag. “He said, ‘I’ll be back,’ ” Mr. Zambas said.

Has anyone gotten sick from attempting to scale Mount Olympus?

Not one person, Mr. Zambas said. “Usually, people know when to give up,” he said. He knows when the gallant gourmands are about to quit, “when they start sweating and change color.” Another telltale sign is when they “start getting up more often to stretch,” he said.

Mr. Zambas, who in 1977 at age 14 fled war-ravaged Cyprus with two siblings and his parents, said Zeus is simply a reflection of American gumption and ambition.

“America has the biggest cars, the biggest buildings,” he said. “Why not the biggest burgers?”

He doesn’t see the Zeus as contributing to the national childhood obesity problem, which President Clinton had pledged to fight Tuesday in an appearance in Washington Heights. The diner’s customers, he said, generally know they cannot finish the whole thing. But how big can a burger become before it ceases to be a burger? Ultimately, how will the burger war end? “That’s the big question. How does it? Not how, but when,” Mr. Zambas said. “There’s only one possible outcome.”