Adam Levine has confessed that when he lifted weights to maintain his toned body, it turned him into a "monster."

The Maroon 5 frontman says that he has not lifted weights or been to the gym in five years and does not miss it at all.

Speaking to Details magazine, Adam revealed that the particular form of exercise did not agree with him.

"Weights made my neck thick, and I would be like, I'm turning into a monster!'" he told the December/January issue of the publication.

"Yoga takes what you have and molds and sculpts it, which is a much more natural way to look and feel."

Adam says he finds the exercise relaxing as well as a way to transform his body and doesn't like that some people suggest it's not a way to keep fit.

"I don't like how people bulls**t about how yoga is not about vanity," Adam shared.

The 32-year-old singer revealed that he has a room backstage at his concerts just to do yoga.

"Playing a show before thousands of people is a highly unnatural state," he said. "When I get on the mat and do an hour of yoga before the show, I come out physically relaxed."

He said that his work with New York City yoga instructor Chad Dennis is "an investment in happiness for the rest of my life."