First, there was the federal guideline: Fill half of kids’ plates with fruits and vegetables. Then came the research: Doing so will boost their consumption of produce.

Building on the well-intentioned guideline, researchers at Penn State University have found that a bountiful plate made kids more amenable to fruits and vegetables.

To determine that, the researchers used two feeding strategies with the study participants, who were between the ages of 3 and 5 years old. In one scenario, they added 50% more produce to kids’ meals throughout the day. In the other scenario, they added 50% more produce as a substitute for other foods such as macaroni and cheese.

Both approaches had a positive effect: Simply adding more produce increased fruit and vegetable consumption by 33% and 24%, respectively. But when the produce was used as a substitute for other foods, the effect was even more dramatic, increasing fruit intake by 38% and vegetable intake by 41%.

For most foods, kids eat more when they are given larger portions. The scientists wanted to determine if that held true for produce. Among the young study subjects, that was clearly the case.

While the strategy improved kids’ produce consumption, they still fell short of the recommended daily vegetable portions for their age group —  1½ cups.

So what’s the takeaway message for parents? The researchers suggest  serving fruits and vegetable as a first course when children are hungry. Adding vegetables into mixed dishes is also an option: Squash can be added to macaroni and cheese. Pureed fruit can go into brownies. Or as most parents will attest: When it comes to produce, whatever it takes.