It's currently Ramadan, the Muslim period of Fasting. Within the Arsenal squad Marouane Chamakh, Abou Diaby, Samir Nasri, Bacary Sagna, and Armand Traoré are all reported as practising Muslims. This period lasts from 1st - 29th August and involves not eating during daylight hours. Chamakh has publically stated that he doesn't fast the day before, and on game days, but makes up the days later. However, the other members of the team may be fasting, and this could possibly be affecting their performances. Obviously it doesn't apply to Diaby and Traore at the moment. And Sagna has played well. Nasri seems OK, but perhaps this is part of the reason that Chamakh hasn't fared so well? We could see an up-turn in his form once this period comes to an end. I'm not saying being a Muslim is a bad thing, before anyone accuses me of that. Religion is a very personal thing, and having this level of dedication to something in your life is often a very positive influence on you as a human being. Simply saying that in the case of Chamakh, perhaps his body isn't functioning at 100% at present.
