Does TV make you fat? There’s a growing body of evidence connecting more TV watching with poorer diets.

The latest study in the field has found that kids who watch more TV than their peers while in middle and high school have less healthy diets five years later. As young adults, they eat more fried foods, fast food and sugary drinks and consume fewer vegetables, fruits and whole grains.

“We can’t say we know the specific mechanism linking TV and diets, but we see this relationship,” says Daheia Barr-Anderson, lead researcher of the study and a scientist at University of Minnesota’s School of Kinesiology. (Kinesiology is the study of human movement.)

Barr-Anderson offers some common-sense explanations for the TV-diet connection. She says that many snack and soda advertisements are aimed at children and can influence their food choices. Plus, many lifelong behaviors are formed in adolescent years, including the preference for snacking while watching TV. 

American adolescents are a noticeable part of the national obesity boom. In the mid-1960s, fewer than 5% of 12-19 year olds were overweight. Today, some 17% are overweight and another 17% are obese.

Harvard researchers have previously found that that for each hour of TV viewing, kids consume an extra 167 calories a day, largely because they eat more junk food and fewer fruit and vegetables, Barr-Anderson tells the Health Blog. Separately, research from the University of Missouri-Columbia suggests that eating family meals and cutting down on TV viewing can help keep kids from becoming overweight.

The latest study is based on a survey of 2,000 middle and high school children in Minneapolis and St. Paul, Minn. Unlike many previous analyses on TV and diets that compared subjects’ behavior at the same point in time, the latest effort tracks behavior in two separate periods. It appears in the International Journal of Behavioral Nutrition and Physical Activity.