FRIDAY, July 17, 2015 (HealthDay News) -- Many people would assume that spending more time sitting at home or work might have a negative impact on a person's diet, but a new study shows no such effect.
Researchers led by Dr. Kerem Shuval of the American Cancer Society looked at the habits of more than 4,900 U.S. adults tracked in two federal health surveys from 2003 and 2006.
While prior studies have asked people to "self-report" their time spent sitting and watching TV, the new study looked at data from "accelerometers" -- devices that track a person's movement (or lack thereof) throughout the day.
The study found that more minutes per day being sedentary -- such as watching TV, driving in the car, or sitting at work -- was not significantly associated with diet quality, or fruit and vegetable intake.
In addition, there was a significant link between higher amounts of sedentary time and a lower intake of low-nutrient, "empty calorie" foods, Shuval's team reported online recently in the journal Preventive Medicine.
That's not to say that there's no benefit to physical activity that gets the heart pumping, however. The researchers found that every minute per day of moderate-to-vigorous exercise was associated with an increase in the quality of a person's diet, including eating more fruits and consuming fewer empty calories.
So why did prior studies find that TV viewing was a linked to a poorer diet? According to Shuval's team, the effect may come not from sitting, but from exposure to ads for high-calorie foods, or the "distracted eating" that often comes with TV viewing.
However, they still believe that too much sitting is an independent risk factor for poor health and needs to be targeted in public health efforts to prevent chronic diseases.
One expert agreed. "Though the findings of this study did not find a significant relationship between sedentary time and diet quality, we certainly should not discount the importance of being physically active," said Dana Angelo White, a sports dietitian and assistant clinical professor at Quinnipiac University in Hamden, Conn.
"There are so many Americans suffering from chronic diseases associated with obesity, the overall message should remain, move more and eat less," White said.
Nancy Copperman directs public health initiatives at North Shore-LIJ Health System in Lake Success, N.Y. She called the study results "surprising," but said that "being a couch potato doesn't help improve the nutritional quality of the diet," either.
"In the past two decades, our televisions have become slimmer and our population has become heavier," Copperman said. "The real take-home message is that as physical activity [exercise] increased in the study, the diet became healthier with increased fruits and vegetables and decreased empty calories."
The U.S. National Heart, Lung, and Blood Institute offers a guide to physical activity.