Getting that booty off the couch will mean less time eating junk food, according to a new study published in the Archives of Internal Medicine.  Experts say small lifestyle changes may have a "domino effect" in helping people lose weight.

Researchers from Northwestern University Feinberg School of Medicine randomly assigned 204 adults one of four different lifestyle treatments. The treatments included increasing fruit and vegetable intake and exercise, decreasing fat and sedentary leisure, decreasing fat and increasing exercise and increasing fruit and vegetable intake and decreasing sedentary behavior. When patients were asked to change one lifestyle behavior, it was easier for them to change others, as well, creating a snowball effect, according to the findings.

"The key take-away is that people can change their unhealthy eating and activity behaviors, contrary to what many health professionals believe.  By focusing on just two targets (increasing fruits/vegetables & cutting down leisure screen time) people were able to make large changes in those behaviors rapidly and they also reduced saturated fat intake without even trying," Bonnie Spring, a professor of preventive medicine at Northwestern University Feinberg School of Medicine, and lead author of the study, told ABCNews.com.

It is important to note that this was not a weight loss study. Only about 60 percent of participants were overweight or obese.  However, 100 percent had all of four unhealthy diet and activity behaviors that characterize most Americans: not eating enough fruits/vegetables, eating too much saturated fat, not getting enough moderate physical activity, and watching too much TV.  Spring said these unhealthy lifestyle behaviors are very important behavior change targets in and of themselves, because they all have long-term adverse effects on health, independent of any effects on weight.

For the first three weeks, study participants were paid $175 to stick to the lifestyle changes and report their progress. When that phase was completed, patients no longer had to maintain the lifestyle changes in order to be paid, but the researchers found that 86 percent of people reported trying to keep with the changes once they were made.

Sitting in front of the television for long periods of time is particularly dangerous, as it creates the "perfect storm" of unhealthy behavior, said Dr. David Katz, director of the Yale Prevention Center. Watching TV and snacking on junk food have become "complementary behaviors" for many people.

While sitting on a couch watching TV, you are 1.) Not getting any exercise, 2.) Seeing advertisements for foods you really shouldn't be eating, 3.) You are probably inclined to eat while watching TV and 4.) You are apt to eat mindlessly because you are distracted from the food by what's on the screen.

"Disaster in the making," said Katz. "Certainly stands to reason that much is to be gained by reverse engineering this."

"People know they need to do better but often have trouble putting recommendations into practice," said Dr. Jana Klauer, a New York-based weight loss and nutritionist specialist.  "The study demonstrates how by focusing on changing one unhealthy behavior leads to improvement in other areas."

Katz said people have opportunities to make simple behavior changes that can be easier and more rewarding as one moves forward. Sitting on the couch in front of the TV is certainly one of them.

"We need both to cultivate the will for health, and pave the way with creative strategies," said Katz. "These authors are clearly thinking along those lines, and I commend their work in this area."

Changing one unhealthy behavior is "great advice for anyone who sits during work," said Klauer.

"Limit your screen time at home," she said. "Walk… or take an exercise class. The nice weather makes it even more enjoyable."