All or most of the major hotels will have at least one restaurant open during lunch. You should also be able to go to some of the food markets (like Carrefour) and buy food during the day to take to your office and eat discreetly (ie., not in front of fasting Muslims). You cannot eat in any public place during the day. We're guests here and must honour the traditions. Last year I just fasted myself during the day and was not any the worse for having done so.