A study has found an association between the amount of fast food that children eat and how well they do in school over the course of several years. Researchers found that the higher the frequency of fast-food consumption in fifth grade, the worse children performed on math, reading and science tests in eighth grade.
Katy Purtell, assistant professor of human sciences at Ohio State University and her colleagues wanted to determine whether fast-food consumption affects how well a child does in school. They analyzed data from 11,740 students who were part of the Early Childhood Longitudinal Study-Kindergarten Cohort and who were kindergarteners in the 1998-1999 school year.
The children completed a food consumption questionnaire when they were in fifth grade. Only 29% of children reported eating no fast food in the week prior to the questionnaire. Around 10% of children reported eating fast food every day, while 10% reported eating it four to six times a week. The remaining children reported eating fast food one to three times in the week before the questionnaire.
The children completed tests in reading, math and science in fifth grade, and then were tested again in these three subjects in eighth grade.
The study found that children who consumed fast food four to six times a week or every day scored up to 20% lower on math, reading, and science tests in eighth grade than those who did not eat any fast food. Children who ate fast food one to three times a week had lower scores on the math test only in eighth grade, compared with those who ate no fast food.
These association was seen even after the researchers accounted for other possible contributing factors for lower test scores, such as the amount of exercise the children got, their amount of television viewing time, their family socioeconomic status, other food consumption, and school and neighborhood characteristics.
The study was published in the journal Clinical Pediatrics.
An association does not mean that there is a cause-and-effect relationship between eating a lot of fast food and poor academic performance. However, other studies have indicated that fast food often lacks nutrients such as iron that are associated with cognitive development.