Molly Sims covers Shape's January issue

Dec 21, 2011 at 1:55 p.m. ET

While you might think that someone covering a fitness magazine has an easy time looking great, that's not the case for Molly Sims.

Shape magazine -- Molly Sims

The multi-tasking beauty says she has to put effort into looking the way she does, which certainly instills hope in the rest of us. The model, actress, designer and host of Lifetime's Project Accessory covers January's issue of Shape magazine and shares some of her top stay-fit secrets.

Celebrity fitness

Celebrities are known for looking perfect. Nothing jiggles, every muscle is taut and toned, and, of course, they make it all look effortless. But getting -- and staying -- in shape isn't easy for most women. That's why we were impressed to find out Sims, 38, has to actually work at keeping her fabulous form looking so amazing. "This does not come naturally," the Southern-born belle tells Shape of her cover-worthy physique. "I have to work out 60 to 90 minutes at least five days a week and stick to a high-fiber, low-calorie eating plan."

In the new issue of Shape (on newsstands December 26), Sims candidly shares her simple tips for feeling fit and staying focused. She also shares her workout moves guaranteed to firm up your lower body.

How does she do it?

Until a couple of years ago, Sims' fitness routine was hit or miss, and her diet philosophy wasn't working for her. Fed up with constant weight fluctuations, she resolved to make a change. "I wanted to be consistent with my exercise, so I committed to working out for 30 days in a row, no matter what," she tells the magazine. "For an hour every day, I did something. I was on the elliptical or the treadmill, and if someone asked me to go to a class -- whether it was spinning, boxing, yoga, you name it -- I went. By the end of the month, I felt so good, I just kept going. I didn't want to lose my momentum."

Molly's fitness tips

Today Sims has many effective strategies that help keep her in top form. We got a sneak peek at some of her favorites.

Bribe yourself: The biggest get-fit obstacle for most people is getting and staying motivated. Get over this hurdle by treating yourself for goals accomplished. Sims sets a weekly fitness goal (like getting up every morning at 6:30 to work out), and when she's kept with it all week, she gives herself something she really wants, like a new handbag or a piece of jewelry.

Drop five fast – and healthy: Two weeks before her wedding to film producer Scott Stuber last September, Sims realized she needed to drop about five pounds -- but she wanted to do it the right way. First, she cut out all salt and almost all oils (even from foods with "good" fats like avocados) and lowered her carb intake. One week before the event she also cut out alcohol and soy sauce, and increased her water intake. "On the big day, my dress fit perfectly and I felt fantastic," the star tells Shape.

Work out with your partner: Sims' parents used to exercise together all the time, a plan that she and her husband have adopted. The couple coordinates sessions together, which helps them both stay motivated.

Try shorter sessions: No time for a full-on workout session? Even just 15 minutes of activity will benefit your body. "Whether it's time on the treadmill or an upper-body routine, you just have to get that heart rate up and keep it there," Sims advises. To really increase the intensity, she turns up the heat in her exercise room.

Knowing how Sims stays so fit is encouraging -- having a great body really does take commitment to regular exercise and watching what you eat.

More get-fit tips

5 Steps to make your fitness resolutions stick
Healthy living tips to stay fit all year long
Top 20 fitness trends for 2012