Pfeiffer, 55, told Britain's Sunday Telegraph newspaper she was in her early 20s when she joined the group run by a "very controlling" couple who believed in breatharianism and put Pfeiffer on a strict diet she said "nobody can adhere to."
The actress said she realized what she was involved in when she met her first husband, actor Peter Horton, who was researching the religious movement led by the Holy Spirit Association for the Unification of World Christianity for a film role.
"We were talking with an ex-Moonie and he was describing the psychological manipulation and I just clicked," Pfieffer told the Telegraph, adding she initially thought of the couple with whom she was working as "kind of personal trainers."
"I wasn't living with them, but I was there a lot and they were always telling me I needed to come more. I had to pay for all the time I was there, so it was financially very draining," she said.