Although the study lasted only three weeks, Blatt says the strategy was still a success. Participants gave positive ratings to the food, which shows that adding hidden vegetables to favorite foods can be a palatable way to boost nutrients while decreasing calories.
For "individuals with a low liking for vegetables," they wrote, covertly adding purees into entrees is just another way of getting them to eat more vitamin-packed vegetables.
Still, the researchers acknowledge that this stealth strategy has its critics.
"Stealth vegetables get a pretty bad rap from dietitians because they say people aren't learning to like vegetables," says coauthor Barbara Rolls, professor of nutritional sciences at Penn State and the creator of the Volumetrics diet, which emphasizes foods, like vegetables, with high water and fiber content. The criticism, however, sidesteps the fact that many Americans can't get past vegetables' taste and texture, says Rolls. Despite years of prodding by health experts and the government, Americans still eat far fewer vegetables than is recommended.
What the study shows is that pureed veggies can be covertly added to a variety of foods without altering their taste and texture, she says. "The point is that the food industry could easily add vegetable puree to their products to help Americans eat more vegetables and reduce their calories."
A childish idea?
But not everyone thinks being sneaky about vegetables is a good idea, or that it's a strategy that can be followed over the long run.
"This can only work in the long term if someone else is doing the stealthing. Imagine how upset people will feel when they find out they have been forced to eat veggies. Treated like children, they will do doubt react like children," says Marion Nestle, a professor in the Department of Nutrition, Food Studies and Public Health at New York University.
Dietitian Helen Rasmussen, who works with older adults at Tufts University's Nutrition Center on Aging, wonders if home cooks will be willing to do the extra work to make the purees. "The people in the study were paid to eat those meals. Would they go to extra lengths to steam and puree different vegetables? Is this really going to solve our obesity problem?"
On the other hand, she adds, "it is an interesting way to offset calories. And if it works for one person, then it's a good idea."
For those who want ideas for adding vegetable purees to familiar recipes, Rolls says her new book, called The Volumetrics Diet Plan, due out spring 2012, will have some recipes for low-calorie dishes with added puree, including the pumpkin bread and squash risotto recipes that follow.
How to hide your veggies >>