Before the most decorated American marathoner can race, before he pounds out 26.2 miles across the five boroughs of New York City, burning thousands of calories and bloodying his feet, he needs one thing in particular.

He needs his himbasha.

The marathoner, Meb Keflezighi, earned a silver medal in the 2004 Olympics in Athens and victories in the Boston and New York City marathons as well as numerous other races by training hard, resting well and eating right.

But, as his large, extended family with roots in Eritrea can attest, he has long had a secret weapon that not only nourishes him, but also reminds him of an ancestral connection at the core of his identity and accomplishment. The himbasha, a fluffy baked bread, almost always arrives special delivery from his mother, Awetash, just before a race.

“If he can’t get it, he’ll eat a bagel,” Merhawi Keflezighi, his brother and manager, said. “But it’s not the same as Mom’s himbasha.”

As he prepared to race Sunday in the New York City Marathon, which he won in 2009 and which will be his 26th and final professional marathon, Meb Keflezighi, 42, gathered with his family and friends for a private reception in Manhattan that included hors d’oeuvres, video messages from Kobe Bryant and Rob Gronkowski, and dancing to Gwayla, Eritrean party music.

“To have them all here is special,” Keflezighi said in an interview after the event Thursday night. “Since it’s my last one, they all wanted to be here for me, and I really appreciate it.”

His is a family of doers in the face of adversity, whether a marathon or political oppression.

In 1981, his father, Russom, walked out of Eritrea, which was then considered part of Ethiopia, when soldiers threatened to kill anyone who supported the Eritrean independence movement. He went to Sudan and then to Italy and eventually moved the family to San Diego. Nine of Keflezighi’s 11 siblings earned college degrees, and four have advanced ones.

His wife, who also emigrated from Eritrea, was a successful banker at Bank of America. Their wedding drew nearly 600 people, which his wife, Yordanos, described as “intimate” since the number could have hit 1,000 if they had followed Eritrean invitation customs to their fullest. They have three young daughters.

Born in Eritrea, Keflezighi had never run competitively before immigrating to America in 1987 at age 12.

In high school, his signature event was the mile. Although Keflezighi was athletically talented, school came first.

Russom would wake up his oldest children at 4:30 a.m. and would teach them English by reading words out of a dictionary. After school, the dining room table would become grounds for a group study hall. No one was allowed to get up until all the homework was complete. In between, Keflezighi would help his father with his various late night jobs, like cleaning banks or offices.

“My dad would tell us, ‘Look, the people who have an education work from 9 to 5 and are home with their families right now, but I don’t have a formal education,’” Merhawi Keflezighi recalled his father saying. “He said, ‘Get your education because no one can take that away from you.’”

While Keflezighi was in high school, Bob Larsen, then the track coach at UCLA, watched him in a meet and saw fortitude that hinted at great distance-running potential. In fall 1993, Larsen visited the family’s three-bedroom apartment in Southern California.

“I get there and I am just really wowed by the family and what they’ve accomplished with so little,” Larsen said. “I offered a full scholarship. Fortunately, a lot of people knew me in San Diego, so they were encouraging. They said: ‘Bob doesn’t give full scholarships. If he’s offering a full, this is special.’ Facetiously a little bit, I say I gave the scholarship not to Meb, I gave it to his family. They have the key on how to motivate sons and daughters.”

Working with Larsen, Keflezighi won four NCAA distance-running championships.

Keflezighi became an American citizen in 1998 and made his first Olympic team in 2000, in the 10,000 meters.

He would make three more Olympic teams. He ran his first marathon, New York City’s in 2002, and vowed never to do it again because it was painful and he struggled to finish. Now, he says he is glad he stuck with it. Just two years later, he placed second in the race.

At the 2013 Boston Marathon, Keflezighi attended as a spectator. He was walking to his hotel near the finish line when two bombs exploded there, killing three people and injuring hundreds. The next year, Keflezighi returned to the marathon as a competitor with four names scribbled on his bib — honoring the people killed at the race as well as a law enforcement officer who was slain by the bombers during a subsequent manhunt. Although far from a favorite, Keflezighi won — the first American man to do so in more than 30 years.

When he was shown crossing the Boston finish line in a tribute video during a New York Road Runners award ceremony Thursday in Central Park, his father stood, raised his left fist in the air and burst into tears. His mother cried, prayed and made the sign of the cross. That was the only one of Keflezighi’s marathons that his parents missed.

“I’m so proud of him for all he has accomplished,” Awetash said in Tigrinya, with her daughter Adhanet translating. “He missed out on a lot because of his running career. Now, we just hope that God gives him age and health so that he can spend time with his family.”

Yordanos, who says she is always nervous before her husband’s races, greeted him immediately after he finished in Boston in 2014, and planned to do the same this weekend.

Keflezighi has suggested before that he would stop running marathons, but now, with his body spent, he says he really means it. He may run some races for fun, though.

“Through my eyes, this is going to be like, ‘Oh, thank you, Lord, finally!’” Yordanos said. “We see all the sacrifices — icing, dieting, training — it’s a 24-hour job, and he’s given so much to the sport. He will walk away knowing he gave it everything he had.”

After decades of eating his mother’s himbasha to power through races, Keflezighi took a moment Thursday to honor her and the rest of his family.

“I joined them for one dance,” he said. “Part of my retirement is spending more time with them.”