So says a study from the Université de Montréal’s School of Psychoeducation warning that watching too much TV at age 2 can translate into bad eating habits in teen years and poor performance in school.

Researchers tracked nearly 2000 Quebec girls and boy born between spring 1997 and 1998. At age two, parents reported on their childrens’ daily TV habits. At age 13, the kids themselves noted their everyday TV and eating habits.

“Watching TV is mentally and physically sedentary behavior because it does not require sustained effort,” said study coauthor 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.”

Researchers found that every hourly increase in toddlers’ TV viewing predicted poor eating habits down the road — an increase of 8% at age 13 for every hourly increase at age 2.

In short, the more they watched, the worse they ate. Teens glued to the tube early reported that they ate more French fries, cold cuts, white bread, regular and diet soft drinks, fruit-flavored drinks, sports drinks, energy drinks, salty or sweet snacks, and desserts than toddlers who didn’t watch much TV.

Every hour increase of TV also forecasted a higher body mass index, less strenuous behavior at school in the first year of secondary school and less eating breakfast on school days.

The American Academy of Pediatrics recommends that kids ages 2 to 5 limit screen use to 1 hour per day of high-quality programs.

Canadian researchers tested their results against that guideline and found that compared to children who viewed less than one hour a day at age 2, those who viewed between one and four a day later, at age 13, reported having less healthy dietary habits and a higher body mass index.

“This study tells us that overindulgent lifestyle habits begin in early childhood and seem to persist throughout the life course,” said Linda Pagani, co-author of the study published in the journal Preventive Medicine.