When Jane Kostelc first started visiting families at home and asking about their eating habits, she wondered if she wasn't overstepping: "I felt like it was really none of my business what they ate for breakfast," she said.

But it wasn't long before families were pulling cans out of their pantries as she showed them how to decipher food labels, or flipped through their newspapers to check out which sale items might be good choices.

Kostelc works on curriculum for St. Louis-based Parents as Teachers, a group that seeks to improve the lives of preschoolers in all sorts of ways by reaching out to about 350,000 families. So far, about 12,000 of those families have learned something about nutrition from the parent group's High 5 Low Fat program.

More than a tenth of American children from 2 to 5 are overweight — according to 2002 figures released last month by the American Heart Association. That's up from 7 percent in 1994 and health experts have been warning of dire health problems if the number of overweight children continues to grow.

Kostelc said Parents as Teachers wanted a realistic way to teach nutrition and reduce bad dietary choices. "It doesn't do any good to stamp our feet and say, 'Don't do that,"' she said.

The High 5 Low Fat program encourages families to get five servings of fruits and vegetables a day and cut fat intake — but tries to do it with small changes.

Those include lessons like "Rate Your Plate," where parents learn how to evaluate what they are eating, or "Shop Smart," with strategies on buying food cheaply while boosting nutrition.

The work behind High 5 Low Fat began in 1996, when Parents as Teachers and St. Louis University's School of Public Health received funding from the National Cancer Institute to address diet-related cancer disparities among the black population.

Susie Nanney, manager of the Obesity Prevention Center at the university and project manager for High 5 Low Fat in the beginning, called it a realistic program.

"We're not telling people to clean out their cupboards and throw out the candy bars. We're not saying line your refrigerator with just broccoli and tofu," she said.

Modifications are key, she explained. If a family enjoys macaroni and cheese, they can be taught how to make it with less fat and to add a vegetable to it. Or a boxed meal might be prepared with skim milk or less butter.

The instructors — or parent educators — who work with families use recipe cards, calendars showing produce in season and other handouts.

An evaluation of the program published last year in Preventive Medicine showed that a group of High 5 Low Fat participants cut their dietary fat by 2 percent and added a half serving of fruits and vegetables to their diets, Nanney said.

She said what seem like small improvements individually can make a significant difference from a public health point of view.

Missouri's Sen. Kit Bond is such a supporter of Parents as Teachers he's seeking $500 million for it or other national programs for children that include home visits.

This March, Parents as Teachers will begin selling a new CD-ROM of its High 5 Low Fat program to those who work with children outside of its organization in hopes of reaching housands of additional families.

And while home visits remain an important part of Parents as Teachers' work, the program also works in the classroom.

Maria Garcia, 18, of Fort Worth, Texas, took part in High 5 Low Fat at her alternative high school for teenage mothers this fall.

She said information about nutrition and how much to feed her children was helpful and she'd used fruit salad and broccoli casserole recipes she'd been given. "It helps you to be healthier, to make better choices about what you eat," she said.

While she said she has not struggled with her own weight, she has seen children who are too heavy and have health problems. "I just don't want my own kids to be like that," she said.