Are there vending machines lurking in the cafeteria or hallways of your children’s school? If so, you may want to learn as much about what is in those machines as you do about the books your child will be reading in the classroom this year.

A study published in Pediatrics found children who live in states with laws regulating the sale of junk food in schools gain less weight – 2.2 pounds for a 5-foot tall 100 pound child - than children in states with no such laws. The findings were based on data from 6,300 students in 40 states. The researchers also found that kids who were obese in fifth grade were more likely to have achieved a healthy weight by eighth grade if they lived in a state with stringent laws against the sale of junk foods in schools.

"We have found that kids eat less junk food when there is less junk food in schools," Dr. Marlene Schwartz, deputy director of the Rudd Center for Food Policy and Obesity at Yale University, told US News & World Report.

Kids eat anywhere from 19 to 50 percent of their daily food intake while at school. Despite healthy food offerings in the cafeteria, machines stocked with potato chips, sugary drinks, and cookies may tempt kids to pick unhealthy snacks. Even elementary schools host vending machines, which bring in revenues of more than $2 billion for money-strapped schools nationwide.

Not surprisingly, that $2 billion worth of unhealthy snacks contributes to the growing numbers of obese children, which has tripled over the past 30 years. Today, more than one-third of children and adolescents are overweight or obese, according to the Centers for Disease Control.

As part of its efforts to curb childhood obesity, the Obama Administration set new nutritional guidelines for school vending machines earlier this year. The new rules limit the amount of sugar, fat and salt that is available to kids during the school day, whether in the cafeteria or in a vending machine.

Unfortunately, the new rules do not limit the intake of artificial food dyes that make food brightly colorful and nearly irresistible to kids. Neon fruit snacks, frostings, candies, soda and more are colored by millions of pounds of petroleum-based dyes. While sugar is usually identified as the culprit in hyperactive children, some studies link the consumption of food dyes to behavioral problems in kids.

Here are some tips for avoiding junk food in school:

1. Talk to your kids about eating healthy foods while at school and pack healthy lunches whenever possible.
2. Ask your school administrator about what is served in the school lunch program and vending machines. Be sure to check whether the school has rules about acceptable snack food served in the classroom or sold for bake sales. (Here’s a great list of healthy snack options from Kathy at Safe Mama)
3. Choose healthier snacks for your kids with less salt, sugar, and fat and watch out for food dyes. Organic foods are the only food category free of artificial dyes. Read labels to avoid foods that have colors with numbers (like Blue #1) as an ingredient.

Does your school have a junk food ban?

(Photo courtesy of kswx_29 /CC 2.0)