The US based study screened more than 1,000 children aged 2 to 5, and found 20 percent were picky eaters. The researchers stress this goes beyond kids who just hate broccoli or have certain dislikes.
For parents, the issue can be a nightmare as children skip entire food groups like fruits and vegetables. Some say doctors blame them for not trying harder.
"We need to do a better job of giving advice to these parents," said Nancy Zucker, study co-author and associate professor of psychology at Duke University.
"The first take-home message is that you're not to blame. The second take-home message is that it's more complicated than we think."
Picky eaters are more sensitive to the texture and smell of food, and have a stronger sense of disgust than other kids, the study found. This ability to experience the world more intensely may also make it harder for them to get a grip on their emotions or focus, the researchers suggest.
"These are just sensitive kids, they see things more intently, they feel things more deeply and that's both in their own internal experience and the world around them. So they have more vulnerabilities to experience taste more vividly, but also more emotions more strongly," Zucker said.
More than 17 percent of kids were classified as moderate picky eaters: These children had a very limited range of foods they would eat and they would not try anything else, Zucker said.
But some experts say obesity remains the biggest issue facing children in the UK, when it comes to eating healthily.
"We're in an age now where we are really going towards a big overweight obesity disaster. It's really important that our parents do educate their babies at a very early age towards healthy eating," said Christian diet and fitness expert Rosemary Conley on Premier's News Hour.
Listen to Rosemary Conley speaking to Hannah Tooley on Premier's News Hour: