"I did eat that day. I was on a very like, you know, greens and vegetables and lean proteins and kale," Aniston told Access Hollywood.
"When I really wanted to have a cheat day. I had to have a kale chip," she added.
The actress also said that she went to great lengths to ensure that her "kibbles and bits" were properly covered.
"I had no taping. I really just doubled my bras. I had a thong and then two pairs of underwear. Why I thought that was going to help protect anything is beyond me. Because, that's just like ridiculous."
"We're the Millers" opens in theaters on August 7.