When the United States' obesity epidemic first got bad in the late 1990s, many people blamed the fast food industry for contributing to the crisis by promoting America’s cycle of unhealthy eating and a sedentary lifestyle. Because McDonald’s and other fast food outlets like Dairy Queen or Taco Bell have been under fire for fueling the obesity epidemic, in recent years they’ve actually made adjustments to their menus to support healthier diets. For example, McDonald’s began phasing out antibiotic-riddled chicken meat and decking out its menus with healthier options like fruit and salads. Wendy’s was one of several chains that removed soda from kids’ menus.

While all of these steps seem positive, it’s difficult to say whether they’re actually making a difference in the diets of U.S. adults and children. In past studies, the restriction of certain high-calorie foods in fast food menus appeared to improve dietary choices in adults, but a new study finds that may not be the case for children. The study, published in BMC Research Notes, finds that quite simply, when children are given a choice between fries and apple slices, they still go for the fries.

“We guessed that children would opt out of a healthier default when much-loved fries were an option,” said David Just of the Cornell Food and Brand Lab, an author of the study, in a press release. “We were surprised that this was the case even for a relatively attractive healthy option like apple slices.”

For the study, the researchers examined 15 children who were between the ages of 6 and 8. They presented chicken nugget meals to the children, and half of the children were given fries with their meals while the other half got apple slices. When asked if they wanted to switch fries out for apples or vice versa, most of the children opted for the fries. Among the kids who had received apple slices for their meals, 86.7 percent chose to switch to fries instead.

Given the extremely small sample size of children, it’s difficult to guage whether all children would make this choice. It does, however, make sense that humans would naturally gravitate toward a saltier, fattier, or more sugary option. Research has shown that our brains can actually get addicted to food. Fast food addiction coupled with the industry’s tendency to pair high-calorie dishes with even fattier sides can make it difficult for people to break out of their diet routines.

It doesn’t have to be so black-and-white, however. The researchers believe that rather than eliminate fast food from the diet, it may be more effective to reduce the amount of fast food consumed, then add in a fruit. “A more realistic solution would be to offer a smaller portion of fries with apples,” said Brian Wansink, author of Slim by Design: Mindless Eating Solutions for Everyday Life, in the press release. “[T]hat way, children aren’t forfeiting their favorite food; they are just eating less of it.”

Source: Wansink B, Just D, et al. The limits of defaults: why French fries trump apple slices. BMC Research Notes. 2016.