Plenty of parents pop their kids in front of the TV in order to steal a few moments of private solace. But one harmful result? Too much screen time as a toddler can result in poorer eating habits and performance in school once the kiddos reach adolescence, according to new research.

In a new study published in the journal Preventive Medicine, researchers followed 2,000 five-month-old Canadian boys and girls born between 1997 and 1998, a release in Science Daily reports. At two years old, the parents began keeping track of how much TV their kids watched each day—and this was long before smartphones, tablets, and health guidelines on the matter existed.

“They were raising their children with TV and seeing it as harmless,” said study supervisor Linda Pagani, PhD, in a press release. “This makes our study very naturalistic, with no outside guidelines or interference—a huge advantage.”

Once the kids hit age 13, they reported on their dietary habits and school behavior. In analyzing the data, researchers found that watching TV as little ones definitely made an impact: For every hour of watching TV as a toddler, there was an 8 percent increase in bad eating habits and a 10 percent increase in body mass index down the road. Adolescents who watched an excessive amount of TV at age two were also shown to put in less effort at school.

“We hypothesized that when toddlers watch too much TV, it encourages them to be sedentary, and if they learn to prefer effortless leisure activities at a very young age, they likely won’t think much of non-leisure ones, like school, when they’re older.” —Isabelle Simonato, study author

“Watching TV is mentally and physically sedentary behavior because it doesn’t require sustained effort,” said study author Isabelle Simonato. “We hypothesized that when toddlers watch too much TV, it encourages them to be sedentary, and if they learn to prefer effortless leisure activities at a very young age, they likely won’t think much of non-leisure ones, like school, when they’re older.”

Since it’s known that the negative effects of binge-watching can plant their roots at a very young age, preventative steps can be taken. Dr. Pagani suggested limiting TV-watching time to an hour a day, tops, for young children. Think of it as motivation for finding other ways to have fun and get outdoors.

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