Many efforts have been made to encourage people to eat better without restricting choice by making healthy foods more visible, attractive and convenient.

One such effort is for restaurants to serve meals with a default healthy side, such as sliced apples instead of fries, while still allowing the customer to opt out of the healthy side in favor of their preferred side dish.

While this strategy has worked well with adults in certain settings, researchers Dr. Brian Wansink and David Just from the Cornell Food & Brand Lab tested this strategy with young children to see if they would opt out of the healthy choice.

The new study findings, published in BMC Research Notes, examined whether children would select apples over French fries when the apples were presented as the default option.

"We guessed that children would opt out of a healthier default when much-loved fries were an option," Just explained. "We were surprised that this was the case even for a relatively attractive healthy option like apple slices."

The researchers bought takeout meal chicken nuggets from a fast-food restaurant for 15 children who were six to eight years of ages. Half of the children were given fries with their meal and told that they could exchange the fries for apples. The other half were given apples and told that they could exchange for fries. The study was repeated the following day and again the following week with the default switched. Even when the default side was apples, 86.7% of the children opted to swap for fries.

The researchers concluded that strongly preferred foods, like fries at fast-food restaurants or red meat at buffets, are so standard that it can be difficult to get people — especially children — to opt for healthier options, even if the healthy option is the default.

"A more realistic solution would be to offer a smaller portion of fries with apples. That way, children aren't forfeiting their favorite food; they are just eating less of it," suggested Wansink, author of Slim by Design Mindless Eating Solutions for Everyday Life.