"The number of hunger strikers has fallen sharply in recent days, from a peak of 89 on June 1 to 18 today," Joint Task Force Guantanamo (JTF) said in a statement.
"The hunger strike technique is consistent with Al-Qaeda practice and reflects detainee attempts to elicit media attention to bring international pressure on the United States to release them back to the battlefield," the statement said.
Four detainees are currently being force-fed, the military said. Two started their protest on August 8, 2005 and the two others on May 29 of this year.
Another prisoner who had refused to eat since August 8, 2005 resumed eating, although he is still classified as a hunger striker, said the statement issued from the US naval base.
The force-feeding is conducted through a tube inserted in the nose, a technique that US officials call "safe and humane."
The force-feeding method, in which the inmate is strapped into a restraint chair, was launched after a major hunger strike last year involving 131 detainees.
Defence lawyers and human rights groups have condemned the practice as cruel and accused the medical doctors involved of violating their professional ethics.
JTF medical professionals counsel the detainees about the health risks associated with hunger strikes, the military said. A detainee is considered on strike if he refuses nine consecutive meals.
The JTF also said the average detainee had gained 8.4 kilograms "and enjoys far better clinical health and access to medicine than when they were removed from the battlefield."
Only 10 inmates have been formally charged as terror suspects among the approximately 460 held there as "enemy combatants" since the camp opened after the attacks of September 11, 2001.