Mr Chalard declared the end of his hunger strike on Sunday (July 6) on his Facebook page.
"At the age of 71 and having been without food for 45 days, I have to accept the fact that I can no longer endure the toll on my health," he wrote.
Mr Chalard said although he had successfully used hunger strikes to fight for elected prime ministers in the past, he was finding that the fight against dictatorship in the current situation was totally different.
"I accept defeat in this round of fighting," he said.
Mr Chalard said his decision came after receiving advice from democracy-loving people. His doctors also told him that if he continued with the fast he would have to survive with a saline injection in front of parliament.
"I have found that it is useless to fight against dictatorship and for a true democracy with this method. Moreover, it deprives me of a chance to fight with the required brain and strength through peaceful means in the future," Mr Chalard wrote.
"As long as I am still alive, I will continue to fight for democracy.
"I will continue my political activities in front of parliament to disseminate truth to democracy-loving people and join the establishment of a political party which belongs to the people, not capitalists or any particular group of people," he wrote. Bangkok Post