Palestinian prisoner rights groups that support the weeks-long hunger strike, however, said in a statement issued soon afterward that the footage of Barghouti eating was old and that Israel was "waging a war of lies".
On Israel's part, a minister appeared to suggest prison officials had been involved in introducing the food into the cell where Barghouti was being held in solitary confinement with the aim of tempting him to eat.
More than 1,500 Palestinian prisoners are currently on hunger strike in Israeli prisons, and they have now been joined by leading Palestinian activist, Leila Khaled.
He said he was unsure whether the release of the footage would help break the strike.
"We appeal to worldwide organizations to act to free detainees from Israeli prisons", Haddad said.
Barghouti, 57, is serving five life sentences for murders committed during the second intifada but is seen by many as a successor to... Barghouti disputed the court's jurisdiction and did not mount a defence, and has been in prison since 2002.
Abu Mazen is the nom de guerre of Palestinian Authority President Mahmoud Abbas. After decades of conflict, hundreds of thousands of Palestinians have been imprisoned at one time or another for acts ranging from stone-throwing to carrying out attacks that wounded or killed Israelis.
Sinn Fein MEP Martina Anderson has condemned the treatment of Palestinian prisoners now on hunger strike in Israeli jails.
Palestinians dismissed the video as a "fabrication".
The release of the footage is the latest development in a fierce battle to control the narrative of the prisoners' hunger strike, which its leaders insist is for improved conditions in Israeli prisons but which Israel says is for political reasons.
"As I said from the very beginning, this hunger strike was never about the conditions of the convicted terrorists, which meet worldwide standards", Israel's minister of public security, Gilad Erdan, said in a statement following the release of the video. He said guards had punished the strikers by seizing all personal items and leaving prisoners "with nothing except their beds".