Fast food has long been linked to obesity, but a new study suggests that it may also affect children's educational achievement.
The study, led by Kelly M. Purtell at Ohio State University, tracked students between fifth and eighth grade, when students are assessed in reading, math and science. Researchers used data from the Early Childhood Longitudinal Study-Kindergarten Cohort, a national survey covering about 12,000 students. In fifth grade, the students were asked how much fast food they had eaten in the past week (the survey was not necessarily given the same week as the academic assessment). Researchers then compared the frequency of fast food eaten to the academic achievement gains between fifth and eighth grade.
Researchers found that students who ate more fast food overall had slower growth in academic achievement. Students who reported eating fast food once a day had slower growth in math, reading and science than students who ate no fast food. The more fast food a student reported eating, the lower their rate of academic improvement.
"High levels of fast food consumption were predictive of lower growth in all three academic subjects," Purtell told The Huffington Post.
The decreases were most pronounced in math. If students reported eating any fast food, their assessments reflected lower gains in math achievement. Meanwhile, lower science gains were related to eating fast food four to six times a week or daily. Improvement in reading was only affected with daily fast food consumption.
According to the report, less than 30 percent of participants had no fast food at all in the week before being asked. About half of participants had eaten fast food one to three times that week. Ten percent had eaten it four to six times, and the remaining 10 percent ate fast food every day.
"These findings indicate that fast food consumption is linked with deleterious developmental outcomes in children beyond obesity," the study says. However, the researchers do not suggest eliminating fast food altogether. Instead, they suggest that reducing the frequency of consumption is a more critical issue.
Purtell said that, based on the results, it is "not as problematic if a family occasionally goes to a fast food restaurant, as opposed to a family that makes it a regular part of their routine."
The researchers theorize that children who eat fast food frequently are not getting the proper nutrients they need to develop optimally. Fast food does not have sufficient iron and has too much fat and added sugar. The study accounted for other possible contributing factors, such as parent education, family income, food insecurity, and TV-watching to show that fast food itself had a correlation to academic scores.
The researchers suggested several ways to counter the negative effects of fast food. First, they noted that parents often give children fast food because it is easy. If food preparation were less stressful, they say, fast food consumption would decrease. They suggest imposing taxes on fast food as a disincentive for those who might resort to fast food for its low prices.
"Fast food is really pervasive right now, and there are a lot of reasons why kids eat it and why families use it," Purtell said. Because of this, Purtell said, "we have to think broadly about lots of different ways to make families not be reliant on fast food."
Fast food is often highly present and available to children. There are many fast food restaurants near -- and sometimes in -- schools, and there is sometimes advertising for fast food in or around schools. If this were not the case, the researchers posit, students might eat fast food less frequently.