Sam frequently drinks Dunkin Donuts coffee. However, from the sound that the cup makes whenever he sets it down, it is apparent that the cup is always empty.
Throughout the series, Sam is often heard urinating in the bathroom on the other side of the door where Dr. Strauss is being held. Yet, for many days, there is never any mention of Dr. Strauss using the bathroom. The chain he is locked to is not long enough for him to get to the bathroom.