6. Let kids serve themselves.
"If you force your child to eat nutritious foods, it can backfire," says Barbara J. Rolls, Ph.D., a professor of nutrition at Penn State University. "Kids figure that if their parents have to force them to eat something, it must not be very good." Serve a variety of foods and encourage kids to have a taste of everything. If they don't like a particular food the first time, don't give up: Research has found that often kids must taste a new food 10 or 11 times before they start to like it.
7. Limit screen time.
While TV has long been scorned for thwarting our kids' physical activity, the number of other sedentary pastimes is growing: computer games, video games, the Internet. Every hour your child spends in front of a screen is time that he could be active. Either limit screen time to a maximum of two hours a day or instigate more physically active distractions to get kids up and moving.
8. Watch the calories in liquids.
Kids, especially teens, can chug juice or soda seemingly in a single gulp—and those calories quickly add up, says Nancy F. Krebs, M.D., associate professor of pediatrics at the University of Colorado. Instead of sugary drinks, offer them water and up to 24 ounces of nonfat or low-fat milk a day.
9. Recruit them to the breakfast club.
"Children who skip breakfast are more likely to be overweight," notes Wendy Wolfe, Ph.D., research associate at Cornell University's Division of Nutritional Sciences. "Kids end up being hungrier and eating more later in the day." Ideally, a kid's morning meal should contain carbohydrates, protein, and a little fat: an egg with toast and fruit or 100 percent fruit juice; peanut butter on a bagel, and a banana; or a bowl of low-sugar cereal with nonfat milk and fruit.
10. Make every step count.
In the 1930s and '40s, kids expended 800 calories a day just walking, carrying water, and doing other chores, notes Fima Lifshitz, M.D., a pediatric endocrinologist in Santa Barbara. "Now, kids in obese families are expending only 200 calories a day in physical activity," says Lifshitz. Incorporate more movement in your family's life—park farther away from the stores at the mall, take stairs instead of the elevator, and walk to nearby friends' houses instead of driving.