If you don't 'encourage every opportunity' for your kids, you're a more successful parent than most, says Harvard-trained expert

Jennifer Breheny Wallace is a journalist, parenting researcher and the author of

Sometimes, the best way for parents to help their kids succeed is to hold them back.

That's according to parenting researcher Jennifer Breheny Wallace. In her recent book, "Never Enough: When Achievement Pressure Becomes Toxic — and What We Can Do About It," Wallace investigates the idea of "toxic achievement culture" and the ways that extreme pressure to achieve can wreak havoc on kids' mental health.

Wallace interviewed psychologists and worked with a researcher at the Harvard Graduate School of Education to survey 6,500 parents across the U.S. (Wallace herself holds an undergraduate degree from Harvard University.)

In many cases, she encountered parents who felt like their children were the ones insisting on signing up for difficult classes and impressive extracurriculars.

"The parents that I met who had the healthiest achievers sometimes held their kids back," Wallace tells CNBC Make It. "They didn't encourage every opportunity. They put up guardrails."

Those children are usually just reflecting the environment around them, she says — trying to stand out amid the increasing competition to get into the country's best colleges, for example.

"Your kid may be driving it, but you put them in an environment where they are getting that social contagion from their peers," says Wallace.

Attitudes and behaviors can be contagious, research shows. Children and teens' anxiety and mental health can worsen simply by being around fellow students who are also stressed out about school or extracurriculars.

When that's the case, you may need to step in and insist that your kid slows down.

"They said, 'Here's the thing. In our home, you have to get eight to nine hours of sleep a night and I'm going to enforce that. You have to have time for downtime with family and your friends. You have to take breaks and rest,'" Wallace says.

Crucially, you may need to slow down, too: Multiple parents of high-achievers told Wallace that it was important to model healthier habits and relationships themselves. Don't overload your own schedule with work. Get enough sleep, and make sure you have regular downtime to spend with your family — where taking breaks to check your email aren't allowed.

"Our kids see the dissonance between our words and our actions when we exhaust ourselves, trying to secure the best for them," Wallace writes in her book.

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