Marianne Zuhorski is keeping up with her workouts as she prepares to have her second child.

She's not counting calories now, but she has in the past with the help of calorieking.com.

"You start tallying it up and it adds up quickly. So it does help you lose weight and watch what you're eating. You just don't realize during a busy day what goes in," says Zuhorski.

She credits the website with helping her shed 25 pounds after her first child.

Mycaloriecounter.com and calorie-count.com are two other websites offering free help counting calories.

Many will even tell you how many calories you're ordering when you eat at your favorite restaurants.

"Body Firm" nutritionist Tammy Parkinson says you can use that information to stick to your diet.

"If you know you are going to go out to eat, go online ahead of time, see what's available to you so you can deduct that from your calorie bank that will enable you to manage your calories every day," says Parkinson.

But these tools will only help you if you're honest about everything that goes in your mouth.

"You want to take a look at: 'am I having salad dressing? What about mayo? And ketchup? Am I having a serving of French Fries, what's a serving -- one cup? Two cups?" Says Parkinson.

In addition to counting calories these websites can also help you learn a few things about what's in your favorite foods.

"The amount of salt is a real eye opener. I couldn't believe it," says Zuhorski.

But registered dietitian Julie Upton warns some calorie counts may be inaccurate.

"No government official is checking these websites that are free and providing nutritional information to make sure they are accurate, so the best source is the u-s government nutrient database. It's the gold standard most dietitians will be using," says Upton.

But she says there's no question these websites are getting people to think twice about their food choices.

Marianne is proof.

"It helped train me better to realize what I was eating," says Zuhorski.

For some, calorie knowledge is power and in some cases will power.