For Olympic debutants Mark and Diana Lopez, it is time to down their favorite fare of chicken and bagels and enjoy their debuts on the taekwondo mats.

From Sugar Land, Texas, the Lopezes, together with brother Steven, will become the first three siblings to appear at the same Olympics since US gymnasts Edward, Richard and William Tritschler competed at the 1904 Olympics in St. Louis.

The three Lopez siblings all won titles at the 2005 World Championships.

Steven, 29, is eying his third Olympic title and a piece of history as the first man to do so in the martial art, while eldest brother Jean will coach Team USA for the second time.

Diana, 24, who enjoys a cheese bagel with apple juice before every fight, is one of the favorites to win the women's 57kg division. She took bronze at the 2007 Worlds in Beijing.

"First fight, last fight - you're going to get them eventually," she said of her opponents before the competition. "But I think, if I'm on, I'm untouchable."

Diana's key rival will be South Korean Lim Su-jeong, who is also fighting for her first Olympic gold.

Though Lim, who just celebrated her 22nd birthday yesterday in Beijing, has not won any world titles, outstanding performances in qualifications make her a genuine contender.

Su Li-wen from Chinese Taipei and Chonnapas Premwaew from Thailand are also rising stars in Asian and international competition.

Lopez and Lim will face Premwaew and Su respectively in the first round.

But 26-year-old Mark, who devours chicken fettuccini alfredo on the eve of his fight, will have a relatively tougher day than his younger sister in the men's 68 kg.

He finished fifth in last year's Worlds in Beijing, and will face Nesar Ahmad Behave of Afghanistan, the silver medalist from last year's Worlds in his first Olympic fight. The 23-year-old Afghan is also expected to win another Olympic medal for his country.

But the draw for this category is also tricky in the way the top contenders, including defending Olympic champion Sung Yu-chi from Chinese Taipei, Gessler Viera from Cuba, Dennis Bekkers from the Netherlands and Servet Tazegul from Turkey, have all been drawn in the second half of the tournament. This gives Lopez and Behave a chance for breakthroughs.

"When they fight, I'm a nervous wreck," Steven was quoted as saying of his brother and sister during training in Beijing. "But I'm thinking about the possibility of creating history. The possibility of all of us going out there and getting golds is feasible."