As the back-to-school supplies signal the eminent return to the classroom, millions of children are enjoying the last days of summer vacation and will soon transition from elementary into middle and high school.

Our schools have become important and influential learning environments and not just in the area of academics. During these impressionable years, the examples set by the adults in charge can have a profound effect in shaping a child's behavior and social skills.

Unfortunately, most school systems are not setting the kind of example one would expect when it comes to nutrition and healthy eating habits.

In recent years, concerns about the rise of chronic childhood illnesses have intensified, particularly the problem of childhood obesity. According to the Centers for Disease Control and Prevention (CDC), the increase of these diseases is related, in part, to poor nutrition.

Perhaps coincidentally, over the past 20 years, middle and high schools have been inundated with junk food and soft drink vending machines. These machines, along with lunchroom snack lines featuring pizza, French fries and fattening desert cakes, serve as intoxicating rivals to healthier mid-day meals.

How can we expect our children to resist the daily temptation of sugary sodas, candy bars and fat-filled snacks when a proliferation of vending machines line the hallways? And why should they...if educators are in essence saying, "this junk is OK?"

A 2003 General Accounting Office (GAO) Report 99 percent of high schools, 97 percent of middle schools and 83 percent of elementary schools offered junk food as an option to their students.

Sorry to say, revenue producing vending machines have become an all too common and easy way for cash strapped school systems to bring in some additional funds. Instead of setting high standards, many schools have become junk food "enablers" and are creating a generation of junk food addicts.

Earlier this year, a group of retired military officers released a report that said over one fourth of America's young people are unable to serve in the armed services because they are overweight and therefore threatened our national security. The report urged Congress to pass legislation that would require schools to provide healthier lunches.

Earlier this month, the Senate passed through unanimous consent the Healthy, Hungry-Free Kids Act, legislation that would improve student lunches and create new standards for all foods served at school, including those in vending machines. The House bill also includes an organic food pilot program but is not expected to vote on the bill until September.

Critics of the legislation have said it doesn't go far enough and would still allow candy and soda in vending machines and foods like pizza to remain on the menu.

Parents need to get involved if their schools are not setting the right example.

With obesity rates doubling in young children and tripling among teenagers over the past twenty years, educating our children about good eating habits is a priceless lifestyle lesson that must be constantly reinforced.

While at school, healthy foods should not be an option...they should be the only option.

Deirdre Imus is the Founder and President of The Deirdre Imus Environmental Center for Pediatric Oncology (r) at Hackensack University Medical Center and Co-Founder and Co-Director of the Imus Cattle Ranch for Kids with Cancer. Deirdre is the author of four books, including three national bestsellers. She is a frequent speaker on green living and children's health issues, and is a contributor to FoxNewsHealth.com. For more information go to www.dienviro.com

Deirdre Imus, Founder of the site devoted to environmental health, www.ImusEnvironmentalHealth.org, is President and Founder of The Deirdre Imus Environmental Health CenterĀ® at Hackensack University Medical Center and Co-Founder/Co-Director of the Imus Cattle Ranch for Kids with Cancer. She is a New York Times best-selling author and a frequent contributor to FoxNewsHealth.com, and Fox Business Channel. Check out her website at www.ImusEnvironmentalHealth.org. Follow her on Twitter@TheGreenDirt and 'like' her Facebook page here.