Middle schoolers without a la carte options ate nearly an entire extra daily serving of fruits and vegetables and stayed within the U.S. Department of Agriculture's guidelines for total daily fat consumption, according to Martha Y. Kubik, Ph.D., of the University of Minnesota and colleagues.
"Our results suggest that the primarily high-fat snacks and calorie-dense beverages offered and sold to students via a la carte programs are displacing fruits and vegetables in the diets of young teens," Kubik and colleagues say.
Campus snack vending machines can also make a difference in daily fruit consumption, the researchers found. For each snack vending machine present in the schools, students' average daily fruit consumption dropped by 11 percent.
An increasing number of schools are offering a la carte and vending options along with more traditional lunches, according to Kubik and colleagues, who note that the school environment can have a powerful influence on students' eating behaviors.
"Interestingly, this metamorphosis in the school environment has occurred during a time when deliberate national effort has been expended to improve the nutritional health of the U.S. population," Kubik and colleagues say.
The researchers collected information on the lunch options and eating habits of seventh-grade students at 16 schools in the St. Paul-Minneapolis area. Thirteen of the schools had a la carte programs and seven schools had snack vending machines that could be used by students.
Kubik and colleagues also examined the nutritional content of the foods that were sold through each of these venues, separating them into high-fat and lower-fat groups.