The Incredible Hulk actress claims the only way she can stick to a keep-fit regime is by making exercise enjoyable, adding using a plastic hoop to tone her tummy is her current favourite.
She said: "I recently got a hula hoop and I've been living in Los Angeles. I put my favourite song on and stand outside and hula hoop in every direction until the song is over and I'm all out of breath. It's really fun."
The 31-year-old actress - who has four-year-old son Milo with her estranged husband, musician Royston Langdon - is determined not to become obsessed with maintaining her toned physique, explaining she tries to focus on the things she likes about her body.
She explained to Britain's The Sunday Times Style magazine: "All you can do really is try your best and accept yourself. I'll always have a more round stomach, but thank God I have thin ankles."
Hula-hooping is not the only unusual pastime of Liv's.
She also drives barefoot, revealing she is so bad at steering a car when she is wearing high heels she has to remove them before starting the engine.