For your choice of number of days (but for no longer than the duration of the Ephes Arc), Sanji is overcome by a deep, unmitigated hunger whenever he is alone. It's never enough to reach a point of starvation, or to immediately compel him to sate it at all costs: sometimes, the hunger only lingers and distracts him like a muted ache. At others, his stomach churns with acid. The hunger gnaws with nibbling teeth, and the mere scent of a paltry glimpse of meat is... irresistible. Whenever he goes at this time, he smells the salted scent of the sea.