The `Hancock` actor doesn`t like to go out into the countryside and is not a fan of nature, unlike the rest of his family - wife Jada Pinkett Smith and their two children, Jaden, 12, and 10-year-old Willow.
The actress claims her superstar spouse - who also has a teenage son Trey with his ex-wife Sheree Zampino - very rarely ventures out with them on outdoor trips.
Asked about what she does in her spare time at the launch of Sony Entertainment Television - which begins broadcasting in the UK on April 7 on Sky Channel 157 - she told BANG Showbiz: "I love to read. I do a lot of yoga, a lot of outside sports. I spent a lot of time out in nature with my kids.
"I try to get Will out but he doesn`t really like nature - he doesn`t` like bugs and stuff. I spent a lot of time there, I do a lot of hiking, surfing, snowboarding. I think that`s what keeps us grounded. There-s nothing like skiing on a huge mountain to make you realise that it`s not about you at all."
Just as her love of outdoor activities helps keep her in shape, the 39-year-old star also insists she is careful about what she eats day-to-day.
She said: "I try to eat small meals at least five times a day and I try to eat clean. I like to do a lot of grilled vegetables, chicken, fish, not a lot of salt, not a lot of sugar.
"I have to be very careful with that because I love sugar. I don`t do pastas and breads because I go up and then I drop and then I`m moody for the rest of the day and that`s a problem!"