Though the 44-year-old star - who has children Apple, 12, and Moses, 10, with ex-husband Chris Martin - has a "pretty healthy" diet, she likes to give in to her cravings and have "pleasure" sometimes, so just accepts she won't feel too good afterwards.
She told Women's Health magazine: "I have a pretty healthy diet, so when I'm eating processed foods and not watching my alcohol intake, I feel it.
"But at the same time, you want deliciousness, you want a fun life - pleasure!
"You're going to have a baguette-and-cheese-and-red-wine frenzy sometimes - but you want it to be a choice you're awake to, 'I know this might not make me feel great, but today I'm choosing it anyway.' "
Gwyneth's Goop launched their own skincare line last year and she admits she did so because she needed something natural that suited her needs as an "ageing actress".
She said: "It started with my wanting luxurious, effective skin care without toxins. I mean, I'm an ageing actress, I wanted that!
"Yes, it's harder and more expensive to make creams and scents and lipsticks without harmful ingredients, but without all the fillers and texturisers, you get pure, powerful actives on your skin."
- Bang! Showbiz
