Hiding Vegetables May Up Intake, Cut Calories

For adults who shy away from eating vegetables, a new study suggests that they can significantly increase their daily vegetable consumption and decrease calorie intake by drawing on a strategy often used for children: hide veggies in their food.

According to the study conducted by a team of researchers at Pennsylvania State University, adults consumed approximately two additional servings of vegetables and 350 fewer calories per day when a variety of puréed vegetables were secretly incorporated into meals, regardless of whether the person disliked the added vegetable.

"hidden" vegetables add nutrition to a meal

"There are cookbooks out there geared toward kids who are picky eaters, but there wasn't any research to investigate incorporating puréed vegetables for adults," said Alexandria Blatt, PhD, RD, lead author of the study and a nutrition researcher at Pennsylvania State University during that time. "We wanted to push our limit to see how much we could incorporate in the foods."

Study researchers supplied 41 men and women with as much breakfast, lunch and dinner as they wanted one day a week for three weeks. Unknown to participants, entrées varied in energy density (calories per gram). One day the meals were standard fare; another day the meals were 15 percent lower in energy density than the standard; and another day's meals were reduced by 25 percent. Energy density was reduced by adding vegetables into the recipes. Meals included unchanged vegetable side dishes.

Participants consumed the food in the laboratory and later answered questions about their liking of specific vegetables. Overall, the three entrée versions all looked and tasted about the same, said Blatt.

Participants consumed approximately the same weight of foods across the three test days. Compared to the standard entrées, participants who ate the entrées 25 percent lower in energy density consumed 357 fewer calories and approximately two additional vegetable servings (487 grams) per day. With the 15 percent lower energy dense meals, participants consumed approximately 200 fewer calories and one more vegetable serving. Whether participants liked or disliked the hidden vegetables did not effect the findings.

Even as the vegetable intake from the entrées increased, participants consumed approximately the same amount of lunch and dinner vegetable side dishes. Ratings of hunger, fullness and palatability were approximately the same across the three test days.

"This study was a proof of principle," says Blatt, "to show that you can increase vegetables and lower calories among people who say they dislike certain vegetables."

For those who want to knowingly conceal their vegetables from view (or taste), the key is matching the foods' colors to the vegetable and experimenting, says Blatt. She suggests adding puréed vegetables to mashed potatoes, pasta dishes or anything with a sauce, which can make foods creamier.

The dishes used in this study included carrot bread (added puréed carrots and squash), macaroni and cheese (yellow squash and cauliflower), and chicken-rice casserole (yellow squash and cauliflower).

This is only one strategy, which can be incorporated with other techniques, to increase vegetables and decrease calories, says Blatt. "If you don't mind knowing that there's vegetables in the [food] then it's great; you can incorporate as much puréed vegetable in there as you want; the ideas out there are limitless."

Macaroni and Cheese

AICR tester observations

Using sharper cheese is important for best flavor.

For best texture, peel squash before puréeing, especially if using zucchini.

Baking enhanced the flavor and texture.

  • 8 ounces macaroni (uncooked) (AICR recommends 1/2 of 8 oz. to be whole wheat macaroni
  • 1 Tbsp. trans-fat free margarine (or butter)
  • 2 Tbsp. flour
  • 1/2 tsp. salt
  • 1 cup skim milk
  • 8 oz. reduced-fat shredded cheese, sharp
  • 1 cup puréed cauliflower
  • 1 cup puréed summer squash
  1. Preheat oven to 350°F. Spray glass 8 or 9 inch square baking pan with cooking spray.
  2. Cook macaroni in boiling water until tender, about 8-12 minutes. Drain.
  3. Melt margarine in sauce pan over low-medium heat. Stir in flour and salt. Gradually stir in milk. Cook, stirring constantly, until thickened. Add cheese, stir until cheese melts. Add puréed vegetables and cooked pasta, stir until mixed.
  4. Pour into greased baking pan and bake covered at 350 degrees F for 35-40 minutes.

Makes 6 – 1¼ cup servings

Nutrition Analysis Per Serving
Nutrient analysis from study
AICR analysis/ESHA Food Processor
  • Calories 300
  • Fat 11 g
  • Carbohydrate 36 g
  • Protein 17 g
  • Fiber 2 g
  • Energy Density 1.28
  • 300 calories
  • 10 g total fat (5 g saturated fat)
  • 37 g carbohydrate
  • 18 g protein
  • 3 g dietary fiber
  • 520 mg sodium

Source: Blatt AD, Roe LS, Rolls BJ. "Hidden vegetables: an effective strategy to reduce energy intake and increase vegetable intake in adults." Am J Clin Nutr. 2011 Apr;93(4):756-63.

All active news articles