Action film fans beware: People eat twice as much food during a fast-paced movie than they would with a slower talk show, which is good and bad news for dieters. The study, published in JAMA Internal Medicine, was performed at the Cornell University Food and Brand Lab, where researchers tested the bounds of mindless eating and provided a suggestion for moviegoers.

Researchers placed 94 undergraduate students in front of two different movies for 20 minutes. One-third of the students were placed in a group to watch the 2005 action film The Island, a third watched the same film without sound, while another third of the students were set up to watch the PBS talk show Charlie Rose. Each group was given the same easy access to copious amounts of M&Ms, cookies, grapes, and carrots as they watched the television. The results were startling.

"We find that if you're watching an action movie while snacking your mouth will see more action too!" the study’s co-author Aner Tal, a post-doctoral research associate in the Food and Brand Lab at Cornell University, said in a statement. "More stimulating programs that are fast paced, include many camera cuts, really draw you in and distract you from what you are eating. They can make you eat more because you're paying less attention to how much you are putting in your mouth.”

Before the students were sent into the movie-viewing rooms, all of the food was weighed, and then after 20 minutes, the food they left behind was also weighed. It turns out The Island movie viewers chowed down on a total of 206.5 grams (g) of food, which was almost twice as much as the 104.3g Charlie Rose viewers ate. Even if the action movie had no sound at all, the students still ate 142.1g of food, outweighing the PBS program by nearly 40g. The study size was small, but the difference in the amount of food students ate was so large researchers needed to mark it down as a notable influence on eating habits.

In order to put mindless eating to good use, the study’s co-author Brian Wansink, a professor and director of the Cornell Food and Brand Lab and author of best-selling novel Mindless Eating, suggested placing healthy snacks in front of you during an action flick. "The good news is that action movie watchers also eat more healthy foods, if that's what's in front of them," he said. "Take advantage of this!"

Wansink is the father of mindless eating and has laid the foundation for research on what our minds tend to eat, why, and how we can trick them. In one of his earliest movie experiments, his research team offered five-day-old stale popcorn to Chicago moviegoers for free and gave some big buckets and others enormous ones. Both held more popcorn than the average person could handle. However, those with bigger buckets ate an average of 53 percent more popcorn, and the cues of people eating around them encouraged them to eat more. It’s all a mind game, and according to their research, most of us overeat because of our family and friends, containers, plates, names, numbers, lights, colors, shapes, smells, and distractions that surround our food, and not because we’re hungry. So why not use the tricks of the trade to eat healthy instead?

Source: Tal A, Wansink B, and Zuckerman S. Watch What You Eat: Action-Related Television Content Increases Food Intake. JAMA Internal Medicine. 2014.