You can lead fifth-graders to carrot sticks, but can you make them eat them?

We'll see. New federal lunch guidelines have gone into effect with the new school year. Schools are designing lunch menus that contain less fat, salt and sugar and offer more fruits and vegetables.

The idea, of course, is to help steer students away from the eating habits that can lead to excessive weight gain and its associated health concerns. As childhood obesity has become more common, those health concerns - high blood pressure, heart disease and diabetes - are affecting more and more young people.

The problem hits close to home. A 2010 study of childhood obesity in New Jersey conducted by the Rutgers Center for State Health Policy looked at families in Camden, Newark, New Brunswick, Trenton and Vineland. It found that children in New Jersey's cities have a much greater chance of being overweight than children nationally.

So healthier school lunches make sense. And some of these changes are easy to make. Whole-grain instead of white bread? Turkey hot dogs? Roasted sweet potatoes instead of tater tots? Baked instead of fried? It's pretty simple for students to get used to those kind of changes.

Others are a little tougher.

For schools to receive reimbursement for lunches, guidelines say students must take a half cup of a fruit or vegetable with each meal. As every parent knows, there can be a big difference between taking those vegetables and eating them.

Giving kids a choice between a math book and a game console would be a pretty ineffective way to teach the multiplication tables. And giving students an alternative to junk food only works if they are taught the lifelong importance of making smart choices.

While the new school lunch guidelines are a good start, they will only be effective if this becomes an educational effort as well as a nutritional one. It's not enough to change options. Schools - and parents - also need to help change attitudes.

Yes, if there were ever a subject that needed to be taught just as much at home as in school, it's this one.

That fact was clear in the Rutgers study, which showed that very young New Jersey children, from 3 to 5 years old, are overweight at a much higher rate than the national estimate. You certainly can't blame that on school lunches.

So parents, teachers and cafeteria workers all have a role in trying to educate students to make good food choices.

Otherwise, this could just become an exercise in filling up trash cans with broccoli.