Obesity affects more than a third of the population of the United States, according to the National Institutes of Health (NIH). As many as 1 in 3 U.S. adults are obese, and more than 1 in 20 have extreme obesity, the NIH report.

The condition is a risk factor for several diseases including type 2 diabetes, cardiovascular disease, and some types of cancer.

Researchers from the Ohio State University set out to examine the link between family meals and obesity risk.

The study - carried out by Rachel Tumin, survey and population health analyst manager at the Ohio Colleges of Medicine Government Resource Center, and Sarah Anderson, associate professor of epidemiology in Ohio State's College of Public Health - found that adults who do not watch TV while eating home-cooked meals with their family may have the lowest chances of becoming obese.

The findings were published in the Journal of the Academy of Nutrition and Dietetics.

Studying the link between family meal practices and obesity

Tumin and Anderson used data from the 2012 Ohio Medicaid Assessment Survey, a survey of the Ohio population conducted via telephone. The study examined adults who lived in Ohio and had eaten at least one family meal in the past week. This brought the study sample to a total of nearly 13,000 respondents.

For the study, the researchers defined obesity as a body mass index (BMI) of at least 30 and calculated it for each respondent based on their self-reported height and weight.

The researchers used logistic regression models to analyze the link between obesity and family meal patterns and practices. They adjusted for factors such as employment and marital status, educational level, ethnicity, and age.

Overall, over half of the participants said that they had family meals on most days of the week. Additionally, 35 percent of the respondents reported having family meals on some days, and 13 percent said that they had them only on a few days.

Approximately a third of the participants were deemed obese, and around a third watched TV or videos most of the time during these meals. An additional 36 percent of the respondents said that they never watched TV or videos during family meals, and 62 percent of the participants said that all of the meals they had with their family were home-cooked.

Quality, not frequency, of family meals may lower obesity risk

The study found no association between the frequency of family meals and obesity risk.

People who had family meals on most days of the week - that is, around 6 to 7 days - were just as likely to be obese as those who had family meals on only a few days - or 1 to 2 days per week. People who never watched TV or videos during family meals, however, were 37 percent less likely to be obese compared with adults who always watched TV. This correlation was independent of family meal frequency.

The lowest risk of obesity was found among those whose family meals were both home-cooked and uninterrupted by TV or videos.

Co-author Sarah Anderson explains the findings:

"Obesity was as common in adults who ate family meals 1 or 2 days a week as it was in those who ate family meals every day. Regardless of family meal frequency, obesity was less common when meals were eaten with the television off and when meals were cooked at home."

"How often you are eating family meals may not be the most important thing. It could be that what you are doing during these meals matters more.

This highlights the importance of thinking critically about what is going on during those meals, and whether there might be opportunities to turn the TV off or do more of your own food preparation."  Rachel Tumin, lead author