(Emiliano Ponzi for The Washington Post)

All right, parents, it’s time for a change. Childhood obesity is a very real problem, and I’ve seen plenty of examples among my patients: a 4-year-old weighing 75 pounds, an 8-year-old heavier than me, a teenager weighing in just north of 350 (and climbing). It’s truly disturbing..

The fight against childhood obesity has gained an incredible amount of attention in the world of public health. Michelle Obama’s Let’s Move campaign has a great Web site about nutrition, exercise and healthful lifestyles. The American Academy of Pediatrics has launched an educational site for parents about similar topics. The Department of Agriculture has developed Choose My Plate, another resource with nearly limitless information about healthful eating. The Centers for Disease Control and Prevention has compiled several pages of statistics regarding childhood obesity.

Schools around the country have taken steps to improve the quality of their meals and to remove unhealthful drinks and snacks from vending machines. But those efforts alone can’t solve the problem: It’s up to you to control what your kids eat.

I know, this is a touchy subject. It’s never easy for me to look parents in the eye and tell them that their child is obese, and it’s even more difficult when the child is in the room. I always emphasize that I’m not bringing these issues up because I disapprove of the young person’s appearance. That’s not the issue.

I talk to children and parents about obesity because I know and care about the long-term health consequences that most kids can’t really grasp. Children who are obese are more likely to turn into obese adults. They are more likely to encounter major health issues such as Type 2 diabetes, strokes or heart attacks — and to die prematurely from complications of these diseases. Just as important, obese children suffer more bullying and emotional stress at school, sometimes leading to severe emotional or psychiatric problems.

But because it’s hard for an 8-year-old to make the connection between finishing off that bag of chips and not living to see his grandkids, he may need your help. Here are a few suggestions to foster good habits that will last a lifetime:

Eliminate liquid calories. One of the easiest ways to chip away at your children’s caloric intake is to get rid of the calories they drink. The only two fluids necessary for life and health are milk (starting with breast milk or infant formula) and water. Once children are obtaining adequate nutrition from a solid diet, there is no need for them to ever drink anything other than water. Not juice. Not Gatorade. Not sweet tea. (Sorry, South Carolina.) Each serving of these sweetened beverages contains roughly 100 calories, in a form that evades your body’s mechanisms for feeling full. The calories from just one serving per day can add up to about 10 pounds of extra fat over a year’s time. Cutting them out can make a huge difference.

Stop buying junk. There aren’t very many 10-year-olds who can drive to the store, load up a cart full of groceries and restock the fridge without at least a little help. If your kids eat junk food, it’s probably because you buy it. It’s a lot easier if you just keep it out of the house: If it’s not there, they won’t eat it. I’m confident that you’ll find this method much more reliable than trusting a 6-year-old to pick a nutritious pear (96 calories) over a pack of sugar- and saturated-fat-laden Ho Hos (360 calories). And — let’s be real — limiting the availability of unhealthful snacks probably wouldn’t be bad for the rest of the household, either.

Eat from a farm. This is my simplified rule for deciding whether something is healthful. You don’t need to read nutrition labels when you pick up a quart of blueberries at the farmers market. Food that grew in the ground is almost always more healthful than something that was made in a factory, put in a box and stamped with an expiration date three years in the future. Too often, parents focus on purchasing organic, gluten-free or GMO-free foods while neglecting the basics of nutrition. Oreos are vegan, and Skittles are gluten-free; that doesn’t mean they’re wise choices. An easy way to put this principle into practice is to shop “the perimeter” at the grocery store, leaving the processed foods in the middle for someone else.

Kick your kids out. Turn off the TV and make your kids get out of the house (assuming there’s a safe place for them to play). Better yet, go with them. Take them to the park, go for a walk or ride your bikes together. Exercise has been shown time and time again to improve physical and mental health. Remember, though, that it’s a lot easier to eat or drink 200 calories than it is to burn them off. Make it easier for your kids by limiting the number of calories they need to burn.

Finally, a word about weight. While it’s important to encourage your children to develop healthful habits, it’s also crucial to avoid teaching them to fixate on the scale. Most overweight children don’t need to be told to lose weight. Typically, all that is required is to make a few changes to keep a child’s weight steady while she “grows into it.” And remember, even if your child’s weight is perfectly normal, good nutrition and exercise are never bad ideas.

Researchers in St. Petersburg, Fla., are conducting a study to determine whether using Fitbit activity trackers and other technology can help teens lose weight. (Whitney Shefte/The Washington Post)

Hayes is a resident physician in pediatrics in Greenville, S.C. His parenting and pediatrics blog can be found at www.chadhayesmd.com.