Entertainment Movies Ben Foster: Taking Performance-Enhancing Drugs for Lance Armstrong Biopic 'Definitely Damaged' My Body Ben Foster says he began taking the drugs, which he characterizes as "all legal," as part of a regimen that "was supervised by a doctor" By Jodi Guglielmi Jodi Guglielmi Instagram Twitter Writer-Reporter, PEOPLE People Editorial Guidelines Published on October 13, 2015 04:45 PM Share Tweet Pin Email Photo: Doug Pensinger/Getty Ben Foster has revealed that in order to prepare to play Lance Armstrong in the upcoming film The Program, he felt he needed to do the very thing that destroyed the athlete: take performance-enhancing drugs. Looking back at that regimen, Foster says that the powerful drugs – which he characterizes as “all legal” – “definitely damaged” his body. “I had a great doctor which helped me handle some of those consequences,” Foster, 34, told BBC. “But it took about half a year to get my levels right and I would say for any athlete, you have to ask, ‘Where are your values?’ ” Foster said he took the drugs before shooting as part of a “program which was supervised by a doctor.” In fact, director Stephen Frears said he was unaware that Foster was taking drugs prior to filming. Foster told the BBC he ingested the drugs “in a contained, doctor-supervised manner to better understand why they took drugs.” Now that he’s experienced the first-hand effects doping can have on one’s body, he does understand why some athletes risk taking them. “[You] go faster, go longer, go stronger. That’s why you take them,” he said. “And they took drugs because they work.” Armstrong famously denied and then later admitted to taking performance-enhancing drugs. The Program is based on the book Seven Deadly Sins: My Pursuit of Lance Armstrong, which details the scandal. In retrospect, Foster admits that the negative side effects of the drugs far outweigh any short-term benefits, and “they also can damage the body in very long-term and in very serious ways.” Besides the drugs and the effects they had on his body, Foster said he was surprised to discover just how grueling the sport of cycling really is. “It’s a brutal, brutal, brutal, brutal sport. And I don’t understand how they do it, and do it for that long,” he said. “The Tour de France is a wicked sport in the way that it’s not just man against man or woman against woman, it’s not flesh against flesh. It’s flesh against machine.” “And this bicycle that’s being locked into something has a punishment to it, unlike anything I have ever seen.” The Program races into theaters Oct. 16.