When children age out of WIC after their fifth birthday, the nutritional quality of their diet takes about a 20% hit, according to a new study.

The research shows that a gap in access to WIC, the US Department of Agriculture’s special supplemental nutrition program for women, infants, and children, leaves many families without food assistance until the child enters kindergarten.

“We were surprised to find that there was this large of a reduction in nutritional quality,” says Travis Smith, associate professor of agricultural and applied economics at the University of Georgia and author of the study in the American Journal of Agricultural Economics.

“But our results show that this program really does work to increase the quality of children’s diets. Now we know that when parents lose access to WIC, they make sure their kid can eat the same amount of food, but they switch to a lower quality of food.”

WIC is geared toward nutritional foods such as whole grain breads, 100% juice, cereal, and other supplemental foods. Pregnant and postpartum women, infants, and children under five years old qualify.

“The focus of food assistance programs in the United States has shifted from simply providing calories to providing higher-quality calories. Both components are still part of what we would consider the big umbrella of food security,” Smith says. “Without WIC, you see a switch from free whole grains to buying refined grains, or from fresh fruits and vegetables to canned, where you might have syrups or additives.”

For the study, the researchers used data from the National Health and Nutrition Examination Survey, a decades-long survey that is conducted by medical professionals. Parents are asked to recall what their child has eaten over the course of 24 hours, and that information is translated to a dietary score—the Healthy Eating Index—accounting for quantity and quality of food.

“As you get closer to each component’s recommendation—say, meeting the daily requirement for fruits or vegetables—your score gets higher and higher,” Smith says. “We saw kids whose Healthy Eating Index score fell by 10 points, which equates to a 20% reduction.”

This is a significant dip, especially at such a young age, Smith says. At a young age, it is important for kids to form healthy eating habits and to have access to foods that might combat any picky eating. This can be referred to as “nutritional knowledge.” Essentially, it takes time and effort to get kids to enjoy some healthy foods, such as broccoli, but an aversion to foods can arise very quickly.

“If we care about helping kids eat better, and we have programs that support that goal, but we also have an arbitrary rule where kids get kicked off WIC and have no food assistance for several months or a year, we could be stepping back,” Smith says. “Then all this progress you make with an individual kid could be wiped away in a relatively short time.”

Read the full article about aging out of food assistance programs by Erica Techo at Futurity.