We've been shivering in sweaters since October. But suddenly, swimsuit season is here. Yikes!

For help in losing that winter weight, look no further than your kitchen.

That's right. Cooking can help you get fat, but it can also help you get thin, if you can make low-calorie versions of your favorite foods, such as pasta, burgers or cheesecake, said Devin Alexander, author of a new cookbook, "The Most Decadent Diet Ever" (Broadway Books, $19.95).

"Twenty minutes in your kitchen can save you three hours on your Stairmaster," she said in a telephone interview from her office in Los Angeles. "My Italian grandmother taught me how to cook. I got fat because of her, and I got thin because of her. If I couldn't cook, I would weigh 300 pounds, because restaurants use a lot of butter and oil."

Alexander struggled with weight as a teen but has maintained a 55-pound weight loss for more than 16 years by learning how to cook healthy. She worked in Hollywood as a personal chef to actors who wanted to drop pounds without feeling deprived.

After hundreds of TV appearances on shows such as "The Biggest Loser," "Good Morning America" and "The View," she now has her own series, "Healthy Decadence" on the Discovery Health channel. She's also written "The Biggest Loser Cookbook," "Fast Food Fix" and numerous magazine articles.

By cooking healthful meals, you're expending positive energy toward food, "instead of making it the enemy," she said.

Although her book has a diet plan, the recipes in it can be used with other diets, she said. "If you're on Weight Watchers or South Beach, you can find recipes that will work," she said. "You can eat a ton of good food for 1,400 calories. And if you don't tell your family, they won't know you're cooking from a diet book."

The trick to giving dishes a healthful makeover is balancing ingredients, Alexander said. "If you just do a straight substitution, you usually are disappointed. If you take your favorite meatloaf recipe and just substitute turkey burger, you'll find out it's too dry. You've got to add some moisture to balance it."

It's not just a matter of switching applesauce for butter or oil in cake recipes, either. "You have to compensate and add more cocoa so it's richer and you don't taste the applesauce. And the cocoa powder also increases the fiber. Then I add a little coffee powder because it increases the cocoa flavor even more. Then I pull out some of the flour so it's not too dry."

The recipes aren't complicated, she said, although you do have to make the effort of following a recipe and dirtying a mixing bowl or a few pans.