One in three children in the United States is already overweight or obese and heavy kids are more likely to become heavy adults. One of the best ways to deal with the issue is by monitoring your child's Body Mass Index or BMI.

Caitlin Lewis fuels her body for a healthy lifestyle that includes the rigors of high school soccer.

Her mother, Patty Lewis, tells us, "She really does eat all her fruits and vegetables and she watches her fat intake and we also exercise as a family and her on her own."

To get to this point, Dr. Steven Sindelar says parents must start early, when children are toddlers, because once the weight is on, the problems start.

Dr. Sindelar says, "They're more at risk for heart problems, diabetes, sleep apnea - just to name a few. The earlier you look at it and intervene, the easier it is to reverse the trend. Once we get kids who are school aged and older and are obese, it is very hard to turn around."

One of the most effective tools to track a child is Body Mass Index. Because it doesn't factor in body types, doctors also consider height, weight, and neck circumference to determine if a child is at risk. A BMI in the 50 percentile is considered average; 85 and above - overweight; 95 percent and above - obese."

Caitlin's BMI is right on track and her mom believes that her teenager is on right on track as well.

Patty says, "I wish I could live my life a little bit more like Caitlin lives hers because she's a lot better than I am. But it's good, it's a good feeling and I also know that they will make those choices for themselves now."

That's a big part of a healthy life.

Eating together as a family remains one of the most effective ways to reinforce a healthy diet. It's easier to monitor what your kids are really eating and the conversation during mealtime helps people avoid eating too quickly.