When the 2012 London Olympics schedule was released six years ago, some Muslim groups claimed it showed a "complete lack of awareness and sensitivity" since they ran entirely during the holy month of Ramadan, which begins on July 20.

There are expected to be over 3,000 Muslim athletes participating in the London Games, each of them facing this collision between faith and science: Should they adhere to the sunrise-to-sunset fasting mandated for Ramadan, or continue with their suggested nutritional intake as Olympic athletes?

[ Related: Saudi Arabia sends two female athletes to London ]

Maher Abu Rmeileh, a judo champion and the first Palestinian to qualify for the Games, told EuroNews he would be fasting during the Games. "I know for sure that this won't affect our performance. We are ready to compete and it doesn't matter if it's Ramadan or not" he said.

But many other Muslim athletes have opted not to fast while competing in London, with some surprising justifications.

Egyptian athletes were given a special dispensation from the nation's high cleric, allowing them to eat and drink during training and coaching. From SNTV:

Boxer Sadaf Rahimi of Afghanistan, who will compete in head-to-toe covering designed for athletes, is another Muslim athlete who found an exception for Ramadan. From TIME.com:

Rahimi has said she will not fast while she is in London, citing an historic exemption for travelers. Ghulam Naseri, an Islamic scholar from her hometown of Kabul, says that the Koran makes allowances for travelers "more than a camel ride away from home." She will make up those missed days of fasting when she is back in Afghanistan and no longer worried about being at her physical peak.

Then there's Mohammad Sbihi, a British rower, who opted not to fast and worked with religious leaders to instead "donate 1,800 meals to the poor, 60 meals per day of not fasting, to fulfill his spiritual obligations," according to Aryn Baker of TIME.

[ Related: Palestinian first ever to qualify for Olympic Games ]

Still, there will be hundreds of Muslim athletes who will choose to follow the tenets of Islam and fast during the London Games; so, will it affect their ability to succeed?

Ronald Maughan, a sports scientist from Britain's Loughborough University, told Reuters that the physical adversity the athletes will face may be balanced out by the strong mental and spiritual benefits from the holy month.

From Reuters in May 2012:

Maughan led a team of scientists who reviewed more than 400 research articles on Ramadan and selected those relevant to sporting performance. They found that "actual responses vary quite widely, depending on culture and the individual's level and type of athletic involvement".

"There are often small decreases of performance, particularly in activities requiring vigorous and/or repetitive muscular contraction," the team wrote in the review, published in the British Journal of Sports Medicine (BJSM) this month.

But they concluded that in most situations "Ramadan observance has had only limited adverse consequences for either training or competitive performance".

That said, many Muslim Olympians are still opting to push their fast until after the competitions are over — as difficult as that is.

Said Australian taekwondo competitor Carman Marton to the Courier Mail: "It is good for our Olympic preparation but obviously we would prefer to do Ramadan when everyone else does it. It is a really good family bonding time."

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