"I think my little fit secret would be mixing up my cardio. I do at least 30 minutes a day. And cutting out sugar and alcohol, you know diet is 80 percent of it," said Catherine Chiarelli, a fitness instructor at Crunch.
Chiarelli says small changes in food and fitness keep her slim, plus keeping fitness a constant.
"I think you should sweat at one point during the day, every day," said Chiarelli.
"I think it's the people who are also kind of like those buzzers who really don't take a lot of time sitting still," said exercise physiologist Jenny Evans.
Evans says those who fidget stay slim, like those who take the stairs in lieu of the elevator and pace at the airport.
To help those who don't, she developed a time saving exercise system called "Hit the Deck," a set of cards with a timer that allows you to take five minutes here and 10 minutes there to chip away at fat while boosting metabolism. Cards vary in intensity like "I'm glistening" or "no sweat," to "sweating buckets."
While she is game for many small exercise sessions daily, she also suggests making these small bouts of movement a bit harder than the usual routine.
"We need to sweat. We need to feel a little bit of discomfort to keep the system functioning optimally," said Evans.
Thirty-five exercise cards of varied intensity and a timer offer a subtle way to sneak in sweat time.
"Every time you do that, you're increasing your energy levels. You're increasing your metabolism. You're burning off stress hormones," said Evans. "That's how your cardiovascular system becomes stronger. That's how your muscles grow. That's how your flexibility increases."
When it comes to food, lean ones often keep carbs like pasta, bread and grains as a side dish with just a quarter of the plate as a portion, leaving another quarter for protein and the other half for fruits and vegetables.
Just like having a fitness routine, those skinnies keep meals regular as well. Eating breakfast along with getting at least two other meals during the day to fight off cravings.
"It is those little things that you start doing for yourself that start boosting your self confidence. I think you start viewing yourself differently," Evans said.