Do you worry that your child isn't eating enough vegetables? Have you ever thought about hiding them in dishes that they do like?

A new study from Pennsylvania State University found that kids ate nearly twice as many vegetables and 11 percent fewer calories each day when pureed vegetables were added to foods they already like. And the best part? The kids didn't notice anything.

All that parents need to start increasing the veggie consumption of their kids is a blender. The strategy works better in some recipes than others, so there is a certain amount of experimenting to do.

"Childhood obesity rates are on the rise, and at the same time children are not eating the recommended amount of vegetables," said Barbara Rolls, one of the study's authors in a press release. "Vegetables have been shown to help lower calorie intake. The problem is getting kids to eat enough vegetables."

Researchers fed meals that were doctored with pureed cauliflower, broccoli, squash, zucchini, and tomatoes to 39 children between the ages of three and six on three separate days. The meals looked the same every day: zucchini bread for breakfast; pasta with tomato sauce for lunch; and a chicken noodle casserole for dinner. But the researchers modified the recipes by adding a variety of pureed vegetables.

On one of the days, the children ate meals made with standard recipes and typical veggie content, but on the other two days the pureed vegetables were added to triple or quadruple each entrée's vegetable content. After the kids ate each meal, researchers weighed the foods to determine how much was eaten. The children ate the same weight of food regardless of whether it was a dish fixed the standard way or the ones doctored with extra vegetables, and they didn't seem to notice the difference. Moreover, the preschoolers doubled their vegetable intake on the days they consumed high-veggie dishes compared to the day they ate the meals fixed the standard way while consuming about 140 fewer calories.

Hiding veggies in food is not deception, but recipe improvement, according to Rolls. Most of the kids in the study met their daily requirement for vegetables with the recipe-doctoring technique. Maureen Spill, the study's lead author and a post-doctoral fellow in nutritional sciences at Penn State, said, "Preparing vegetable-enhanced entrees is a technique that should be used with other strategies, such as providing vegetables as snacks and side dishes. Together these strategies can substantially increase children's vegetable intake while also teaching them to like vegetables."

Rolls said this technique can be used for the whole family. In previous research she found that adding pureed vegetables to adults' meals increased their intake of veggies while providing fewer total calories. The extra vegetables weren't noticed by most adults either.

All that parents need to start increasing the veggie consumption of their kids is a blender, said Rolls. The strategy works better in some recipes than others, so there is a certain amount of experimenting to do. Food companies have begun to use the pureed veggie technique to add vegetables to their products. Kraft has begun adding pureed cauliflower to some of its boxed macaroni and cheese while other companies have begun adding other veggies to their tomato sauces.

The study was published online July 25, 2011 in the American Journal of Clinical Nutrition.