More than 40 detainees stopped their hunger strike last week.
The recurring protest started in August and reached a peak of 131 hunger strikers in September.
Some detainees have refused to eat for several months, Lieutenant Colonel Jeremy Martin, the director of public affairs, told reporters visiting the Guantanamo Bay base.
"There is a core group that is very committed," Martin said. "We counsel them on the hazards of a long term hunger strike."
Military authorities count a detainee as a hunger striker when he skips nine straight meals and removes him from the list when he has eaten three times after ending his fast.
If they become took weak or malnourished, detainees are force-fed with intravenously or through a tube inserted through the nose to reach the stomach.
Journalists were invited to Guantanamo to attend a preliminary hearing on Wednesday for the military trials of two detainees, a Canadian and a Yemeni.
Meanwhile, State Department spokesman Sean McCormack has defended Guantnanamo, saying "Guantanamo serves a purpose, and it's there for a reason".
"It keeps people who are very dangerous away from civilised society."
He was responding to remarks over the weekend by Germany's chancellor, who said such facilities shouldn't be allowed to exist indefinitely.
Guantanamo holds about 500 detainees, including Australian David Hicks. Most detainees were captured in Afghanistan in late 2001 following the September 11 attacks on the United States.