Kids who spend too much time watching TV or playing video games could face an increased risk of type 2 diabetes, according to new research from the University of London and the University of Glasgow.

However, parents can use a number of tools to help kids keep their screen time under control.

The study, published this week in Archives of Disease in Childhood, looked at data on health factors such as body fat for almost 4,500 9- and 10-year-olds. The children were also asked about their daily viewing and gaming habits.

Eighteen percent of the youngsters reported regularly spending more than 3 hours per day engaging with electronic devices. These children were more likely to have two significant risk factors for type 2 diabetes.

They were, on average, 11 percent more resistant to insulin, and they appeared to have more body fat. (With insulin resistance, the body can't respond to the hormone insulin properly and consequently can’t easily absorb glucose from the blood.)

The data were collected between 2004 and 2007, the year the iPhone was introduced. Today, kids might spend even more time with digital devices, according to the study’s lead author, Claire Nightingale, Ph.D., a research fellow in medical statistics at St. George’s, University of London. "An association between screen time and risks of type 2 diabetes has been shown in adults” in prior research as well, she says.

What Parents Need to Know

Scientists have conducted a number of studies on the health risks people might face because of too much screen time.

David Hill, M.D., chairman of the American Association of Pediatrics’ Council on Communications and Media, says the main culprit might not be a lack of exercise, but a surplus of junk food.

Bingeing on TV “definitely seems to lead to a less healthy diet,” he says. A 2013 study published in the journal Pediatrics (PDF) showed that the more time children spent watching TV, the more likely they were to have a higher-than-normal body mass index, or BMI, a measure of body fat based on height and weight.

Contributing factors might have included a heavy dose of junk-food ads together with the mindless munching that can come when kids are engrossed by a favorite cartoon. (The effect was less pronounced for video games.)

For parents, the first step in limiting their children's screen time is to apply the tech version of the golden rule: Model good behavior.

According to a report from Common Sense Media, a nonprofit group that works on technology issues, many parents set a bad example. They average 9 hours per day in front of screens, with only about 90 minutes of that time dedicated to productive work.

“If you’re addicted to your phone, don’t be surprised if kids follow your example,” says Corrina Lawson, senior editor at the GeekMom, a tech and parenting site. “The kids learn from you.”

Here are more suggestions:

Set Rules—and Stick to Them

The American Academy of Pediatrics recommends setting hours-per-day limits for kids; the organization offers a media time calculator to help you determine appropriate limits, taking into account a child's age, sleep habits, and other activities.

Once you come up with these limits, stick to them, experts agree. “I’m all for setting some firm black-and-white rules,” says Kim Moldofsky, the publisher of The Maker Mom, a site that encourages interest in STEM subjects (science, technology, engineering, and math). “Once you start making exceptions, there’s an exception for this and an exception for that, and soon the whole rule is out the window.”

Control the Devices

This classic advice is as useful as ever: Keep computers and game consoles in a communal space such as a family room. And at dinnertime, or on a phone-free Friday, force everyone—including adults—to “check” their phones into a drawer or box.

Some newer technologies can help, too. Routers such as Google WiFi and Eero have easy-to-use mobile apps that can help you control screen time. For instance, you can quickly pause WiFi access during dinnertime or block specific devices—such as your children’s tablets—during designated study hours.

Mobile apps called Moment and Screen Time don’t prevent children from using a smartphone, but they do track time spent. Often that’s all the motivation a person needs to cut back—including you. “Even adults lose track of time,” Lawson says.

Provide Alternatives

The best way to cut back on screen time might simply be to offer better options. “I fall on the side of trying to immerse kids in real life as much as possible,” Moldofsky says. 

“If you see your kids spending too much time glued to the screen, a long-term solution is to sign them up for a soccer league," she says. "In the short term, you can insist that the dog needs a walk.” Or play a board game, go on a hike, or throw a ball around with your kids.

Also, remember that the enemy isn’t necessarily the screen—it’s the suite of couch-potato habits that go with it. An alternative, Lawson says, is to get your kids interested in Pokémon Go, a popular mobile game in which players run around town collecting virtual beings tied to real world locations. (Just make sure they watch where they're going.)

“There are creative ways to use screens that don’t depend on you sitting around all day,” she says.