University of Illinois on top form

From the College of Agricultural, Consumer and Environmental Sciences:

When low-income families devote three to four extra minutes to regular family mealtimes, their children’s ability to achieve and maintain a normal weight improves measurably, according to a new University of Illinois study.

"Children whose families engaged with each other over a 20-minute meal four times a week weighed significantly less than kids who left the table after 15 to 17 minutes. Over time, those extra minutes per meal add up and become really powerful," said Barbara H. Fiese, director of the U of I’s Family Resiliency Program.

I thought that stereotypical "low-income families" eat their meals while sitting on the couch watching TV rather than at a table, so how on earth are you going to decide which period was actually "mealtime" as distinct from "snacking"?