Scarlett Johansson says she feels "bloated" if she stays still after eating.
The 29-year-old US actress is known for her enviable figure, which has earned her the Sexiest Woman Alive title from publications such as Esquire and Playboy in the past.
Although she doesn't follow a strict diet to keep in shape, Johansson strives to be active after tucking into a big meal.
"I am one of those people who feels bloated if I sit around too long eating and drinking and not exercising," she explained to British magazine You.
"So I may hit the gym a bit more [in the New Year], but not as punishment or out of guilt but because I feel physically and mentally better when I exercise. And it's nice time out for myself."
Johansson feels comfortable venturing out in public by herself, crediting her petite stance for keeping her hidden.
However, she sometimes feels pressure to dress appropriately at the risk of being snapped by paparazzi.
"Most of the time I walk round by myself because I am pretty short, so people don't tend to see me! I used to worry more when I was younger, even trying to disguise myself, but now I feel more comfortable to just be me," she explained.
"There are certain things I see that I think, 'God, I would love to wear that if I wasn't recognisable.' I think if I was just an anonymous person I would probably have a much more exciting day-to-day wardrobe. So I just have to appreciate the clothes I love but can't wear by encouraging other people, like my girlfriends, to buy and wear them."