Military spokesman Sergeant Justin Behrens told journalists on Friday that the number of prisoners on strike was decreasing, though ten prisoners had to be fed through nose tubes but were in "stable" condition.
"Ninety-two was the max on hunger strike but it has now dropped down to 87," Behrens said. "Ten of them are being fed through medical assist."
The hunger strike began on 8 August, when the military initially said 76 inmates were refusing food.
The Centre for Constitutional Rights (CCR) said the strike was set off in part by alleged beatings of prisoners, denial of basic needs, and lack of fair trials.
It maintained that lawyers have found that 210 prisoners were taking part in the strike. CCR also said lawyers for prisoners who were on strike were blocked from meeting with their clients.
A federal court late last month ordered the Defence Department to grant attorneys for the firm of Sherman and Sterling access to its clients, it said.
The US military reported 51 hunger
strikers at Guantanamo in July
The strike is the latest in a series that have broken out since 2002 amid protests over the treatment of prisoners at the detention centre.
The prison, long a source of international controversy, is located on a remote US naval base forcibly leased from Cuba.
The military has given the International Committee of the Red Cross access to the prison and hosted tours for visiting journalists and lawmakers. But it remains tightly controlled and largely shut off from the outside world.
Previous hunger strike
The most recent previous hunger strike was from late June through to 28 July, according to the CCR, which maintains that up to 200 prisoners participated, almost four times more than reported by the military.
"In fact, from early July through [to] 25 July 2005, the hunger strike became so severe that the [Pentagon] was forced to place approximately 50 men on IV's," or intravenous feeding, the centre's report said.
"Medics could not manage the detention centre's need and elected to stop making their regular medical calls. The prisoners spent 26 days without food," it said.
"The breadth and severity of the June-July 2005 hunger strike forced the [Pentagon] to permit the creation of a prisoners' representative committee to negotiate with prison officials concerning the protesters' demands," it said.