JOIN USWith the knockout rounds of the World Cup coinciding with the beginning of Ramadan, Muslim players must decide whether to observe the month-long religious fast which begins this weekend.
France, Germany, Switzerland, Belgium, Algeria and Nigeria are among the teams that have Muslim players who may choose to observe the 30-day period of fasting and reflection.
During Ramadan, the ninth and holiest month in the Islamic calendar, all healthy adult Muslims are expected to refrain from eating and drinking during daylight hours.Such a scenario could play havoc with the tightly-controlled diets of elite professional athletes, especially in the hot, humid conditions in which some World Cup games in Brazil are being played.
"The challenge is mainly trying to maintain hydration on a daily basis, and secondly trying to maintain energy levels," Emma Gardner, performance nutritionist at the English Institute of Sport, told Reuters.
"Muscle mass is also an issue. Research suggests that people can lose muscle mass through the period of Ramadan, although it tends to be during the early period," she said.
Gardner's comments appear to be at odds with those of Jiri Dvorak, FIFA's chief medical officer, who told a media briefing on Monday that players observing the fast should not suffer any deterioration in their physical condition.
"We have made extensive studies of players during Ramadan, and the conclusion was that if Ramadan is followed appropriately, there will be no reduction in the physical performances of players," Dvorak told reporters.
All healthy adult Muslims are expected to observe the month-long fast, although exceptions can be made and the fast postponed.
One player who has made up his mind is Germany's Mesut Ozil. "Ramadan starts on Saturday, but I will not take part because I am working," he told a press conference on Wednesday.