Gwyneth Paltrow is "sure" her kids eat junk food when she's not around.

The Goop founder tries to stock her cupboards with "healthier" snacks but is happy for Apple, 18, and 16-year-old Moses - who she has with ex-husband Chris Martin - to make their own choices, even though they wouldn't be what she'd opt for.

She said: "My philosophy is in the house I try to have healthier things around.

"But they have free will and when they're out of the house, I'm sure they go for the Oreos and the McNuggets. More power to them."

And the 50-year-old star - who is married to Brad Falchuk - won't "force" her clean-living lifestyle on her kids, but she's happy her daughter is more interested in the subject now she's older.

She told E! News: [Moses is] 16 and he will barely let me give him a vitamin, so it's also like, knowing when to relent and give him his space.

"I try not to force anything on them. They were raised in an environment where wellness is important and they will adopt what they choose to, or not. They have free will. Apple, she tends to be more wellness-curious now at 18 than she was when she was kind of like smack in the middle of her teens, so we'll see."

While Apple occasionally joins her mother for exercise classes, she draws the line at going for walks with Gwyneth.

The 'Politician' actress said: "She doesn't like to hike with me. She's not feeling it."

But Moses is more keen to spend time in the great outdoors with his mom.

She added: "Moses will take walks with me, so that's great, and he likes to skateboard too, so often times, we'll walk and he'll skate next to me and that's fun."