Tempted to buy a box or two of your favorites when the Girl Scouts come knocking during their annual cookie drive, but worried about loading up on artery-clogging trans fats? Good news: Now you can have your cake—er, cookies—and eat them, too.

In a sign of the times, Girl Scouts of the USA announced that all 12 varieties of their cookies—including top sellers Thin Mints, Samoas, Tagalongs, Do-si-dos and Trefoils—are now free (or close to it) of trans fatty acids, an ingredient in many lards and solid cooking oils implicated in heart disease.

"We want the girls to feel confident and comfortable that they are selling something that is a healthy snack or treat compared to things with lots of trans fats in them," says Michele Riggio, the organization's manager of corporate communications. "I think people are always looking for healthy alternatives and we hope that when they make their choice, it will be a Girl Scout cookie, because they know, relatively speaking, it's a healthy indulgence."

She says Girl Scouts worked "diligently" over the past few years with its bakers to reduce trans fats in its cookies; this year, all varieties sold will meet or exceed Food and Drug Administration (FDA) guidelines that call for less than 0.5 grams of trans fats per serving, allowing them to claim "zero" trans fats on nutrition labels. (The FDA requires disclosure of the amount of trans fats per serving on all packaged goods.)

But fear not: The group promises the new, healthier versions have "the same great taste that has made them one of America's favorite treats" since the popular Cookie Program launched in 1917 in Muskogee, Okla., (where the Mistletoe Troop baked and sold cookies in its high school cafeteria).

The FDA estimates that Americans get 40 percent of their trans fats—long used as a substitute for saturated fats in baked goods, fried foods, margarine, salad dressing and other fare—from baked goods. Trans fats are produced during a process called hydrogenation (adding hydrogen to vegetable oil) used to make some foods—especially bakery items—taste better and stay fresh longer on store shelves. Trans fats raise low-density lipoprotein (LDL) or "bad" cholesterol levels that block arteries, causing strokes and heart attacks. Trans fats also lower the level of high-density lipoprotein (HDL) or "good" cholesterol in the blood.

A 2006 Harvard University study found that eating just five grams of trans fats daily could up the risk of heart disease by 25 percent. Researchers concluded that eliminating trans fats from the American diet could prevent 6 to 19 percent of heart attacks and related deaths annually.

Bowing to pressure from consumer groups and health officials, some fast food chains have voluntarily replaced trans fats with healthier, unsaturated fats like olive, sunflower and canola oils. New York City late last year banned restaurants from serving fare containing trans fats and other cities are considering similar measures.

The Girls Scouts organization estimates that Americans now purchase a whopping 200 million boxes of its cookies a year. (The girls, ages five to 17, decide how to use the proceeds of the sales, all of which—minus bakers' fees—are pumped back into local Scout chapters.) But remember: just because they're trans fat–free, doesn't mean you should down massive amounts.

"As much as we love Girl Scout cookies, we still recommend that any type of dessert or snack be eaten in moderation," Riggio says. "We are not advocating eating a box at one sitting. It's a sweet indulgence to be eaten in moderation."