Kate Hudson isn’t just a successful actress; she’s also an entrepreneur working on a line of workout gear for women. As co-founder of Fabletics, she says she runs and does Pilates to keep her figure trim, but there’s one big rule to follow if you want to stay fit: repetition.

“You can’t do two weeks and go and do two days, then take a week off, and be like, ‘Why aren’t I in shape?’ “ she said.

Hudson says that staying in shape requires “working your ass off”, which is unfortunate for those of us who either can’t find the time or energy to get in a good workout every day. But for many, the key to keeping the weight off is indulging in treats every now and then, in moderation, in order to keep from backsliding. For Hudson, the temptation of a double burger and fries is the strongest when she’s ready to give in on her diet a little.

The 35-year old actress told Women’s Health earlier this year that for her, exercise is great not just for her body, but for her mind as well.

“Everybody loves results. But I think that for me, the most motivating factor is what starts happening to your brain: how we become more clear, how we actually find ourselves having way more energy, how our memory starts to become sharper. The more active you are, the more present you are, the more eloquently you start to speak because your brain is just firing differently,” she said.