Here are two reasons why your tween may be constipated. Plus, strategies that spell relief.

Constipation Cause: Junk Food

Is your preteen trading that turkey on whole wheat for chips or Twinkies at lunch? "Eating junk food or high fat foods won't cause constipation per se, but most kids who have a higher fat diet are not consuming enough fiber," says Dr. Cochrane.

How to Treat: Think Fiber

Keep precut veggies and fruits in clear containers in the fridge, ready for post-school snacking. (Don't forget the dips! Yogurt is tasty with fruit, low-fat salad dressings; fiber-packed hummus is good with peppers and carrots). If the kids can see the healthy snack and it's ready to go, they might be more inclined to eat it. Or kids can snack on bran cereals instead. 

Constipation Cause: Stress

 Are you and your partner dealing with an impending divorce? Is your child worried about the looming prospect of junior high? Is your son getting regularly picked on by the class bully? "Stress doesn't create constipation but it can contribute to it," says Dr. Heyman. "If kids feel out of control in a situation, the one thing they can control is their bowel habits." And so they tend to hold their stool in. 

How to Treat: Talk it Out 

The best thing to do is talk to your child and form a plan of action from there, depending on the source of the stress. If it's a divorce, for example, consider counseling. Or if it's a bully, create a strategy plan with your child and school officials to deal with the issue.