People who watch excessive amounts of television tend to eat more junk food and have a poorer understanding of healthy nutrition, a study has found.

According to US researchers, a number of previous studies have found a link between time spent in front of the TV and unhealthy food consumption.

"In essence, the number of hours of TV you watch per day, the more unhealthy foods you eat. A common explanation for this is that TV watching is sedentary and encourages snacking," explained Prof Temple Northup of the University of Houston.

However, he pointed out that until now, there has been very little research into the psychological reasons for this link.

"There was very little prior research on the psychological reasons this relationship might exist beyond that it's a sedentary activity that encourages snacking. I wanted to investigate underlying psychological reasons that this relationship might exist," he said.

The researchers assessed the TV-watching habits and diets of almost 600 people. They found that those who watched high amounts of television tended to eat more unhealthy foods and had a poorer understanding of a healthy diet.

"I found people who watch more TV had both a poorer understanding of proper nutrition and a more fatalistic view toward eating well compared to those who watched less TV. In turn, those two items predicted snacking behaviors," Prof Northup said.

He noted that people are being inundated with mixed messages. On the one hand, they are constantly seeing ads for unhealthy food and drinks, and characters in programmes consuming these products, but on the other hand, they are being told to avoid eating them.

"If these are the messages, those who watch a lot of them may become less able to determine what is healthy," he commented.

Prof Northup said it is important to understand how people develop knowledge about nutrition, ‘including examining nutritional messages found within the media'.

He suggested that aside from reducing the amount of television you watch, people who are tempted to eat while watching TV should reduce the amount of unhealthy snacks they have in their homes.

Details of these findings are published in The International Journal of Communication and Health.