The next time you turn on a late-night television talk show, make sure you’re not eating, or you’ll likely overeat. That assumption comes from new research to be presented Saturday, June 2, at The Endocrine Society’s 89th Annual Meeting in Toronto.

Past studies have suggested that people eat more when they are in front of the tube, but it’s not clear why. To test whether distraction is what makes people eat more while watching TV, Dr. Alan Hirsch, founder and neurologic director of the Smell & Taste Treatment and Research Foundation in Chicago, measured potato chip consumption in 45 subjects during five-minute periods over three weeks. Subjects ate as much as they wanted while they viewed a monologue by Jay Leno, while they watched a David Letterman monologue, and while they did not watch TV. Participants did not know the true purpose of the study, and the order of the three test settings was randomly selected.

Subjects munched an average of 44 percent more chips while watching Letterman and 42 percent more of the snack food while viewing Leno than when they watched no television. Although both sexes ate more while tuning in to TV, the effect was greater in males. No differences were seen based on body mass index (a measure of body fat), self-reported dieting, enjoyment of potato chips or rating of how much they enjoyed the monologue.

At each session, subjects were asked to concentrate on the sensory characteristics of the food, such as taste and smell. Researchers believe that these sensory clues, in addition to internal body changes, signal satiety, or a sense of fullness.

“The more attention one pays to the taste of their food, the fuller one becomes,” Hirsch said. “If distracted when eating, one feels less full and eats more.”

Although others have said that commercials are responsible for an increased food intake during TV watching, Hirsch disputed this, given that the monologues were commercial free. “It’s just being distracted,” he said. “It’s possible that the more interesting the show, the more distracted one will be and the more one will eat.”

Hirsch called for more study of this attention component of food consumption, as a possible way to lose weight. Based on the findings of his study, he made this recommendation: “If you want to lose weight, you should turn off the television while eating.”