Woody Harrelson believes bad food is the "number one" killer.

Speaking to ShortList magazine, he said: "Of the crucial areas - if you consider that people have self-destructive activities - their food is probably number one I mean, the road to the grave is through the mouth."

The 51-year-old actor has become known for his environmental work and his support for the legislation of marijuana.

Woody insists he is active and vocal about these topics because he is passionate about them and he isn't concerned if his beliefs detract from his acting success.

When asked if he thinks his sometimes controversial views have overshadowed his work, the former 'Cheers' star explained: "But who could I attribute that to? If it's a bother, I have to blame myself, because I have talked about it.

"I like to think I'm doing good work as an actor and that I've helped a few people."

Making it clear that he is not bothered if his beliefs have irritated other people, he added: "So if what I've done has annoyed people, so what? I certainly helped some people."

Woody was named PETA's Sexiest Vegetarian in 2012 along with Jessica Chastain.