Wednesday, April 29, 2015

But WHY Is There A Correlation Between TV and Obesity?

I read an article the other day about a study that found (again) a correlation between TV watching and obesity in kindergartners and first graders. According to the article, the study found that these young children who watched more than two hours of TV a day had a much higher risk of being overweight or obese than children who watched less than one hour. But children who watched between one and two hours also had increased risk of obesity, even though the AAP suggests a maximum of two hours of TV per day for that age group. The takeaway here is, more than one hour of TV a day in 5 and 6-year-olds correlates to a greatly increased rate of obesity.

A simple response, then, is, "Kids shouldn't watch TV." But it isn't that simple.

Two things stick out for me.

1) This is a correlation, not a causation. They did not say that watching TV causes obesity. They even stressed that in the article. We see a correlation, but we don't know why. Why does watching more than an hour of TV seem to correlate to higher obesity rates? They also found that using a computer more than an hour a day did not have the same correlation to obesity, so it isn't the use of a screen, or the sitting and staring, that's a problem. It's the TV, specifically.

2) Didn't we already sort of know this? I mean, researchers have been studying TV watching for decades, and every so often they come out with another study that says, basically, "Kids are watching too much TV and it's making them fat." But they still don't know why. They used to think it was simply because TV was replacing physical activity, but that doesn't seem to be the case, exactly (see above).

Another article reported one older theory as to the reason TV watching correlates to obesity: It's the commercials. Kids are exposed to commercials that make them crave unhealthy food, and that contributes to weight gain. This is an interesting theory. To me, it makes sense, then, to study what kind of TV kids are watching, and how. With Netflix and other streaming services enjoying such high popularity these days, lots of kids are avoiding commercials. My kids rarely see commercials because they watch their shows on Netflix and Amazon Prime. So if there were a study that took two groups of kids, one that watches more than two hours of TV per day but exclusively on an internet streaming service, and one that watches more "traditional" network TV and are exposed to commercials, would we see a difference in obesity rates?



I'd like to offer a few other questions that should be asked.

- Are the kids who are sitting and watching TV more likely to be snacking while they watch?

If so, what are they snacking on? Perhaps kids using computers and iPads are not eating, because their parents don't want sticky fingers on the electronics. In this case, there should be a difference between TV-watching and other screen use, but there should not be a difference in Netflix versus network TV.

- Why are these kids watching so much TV?

Maybe the TV-watching and the weight concerns share the same underlying cause, rather than the TV directly causing the obesity. The L.A. Times article linked above said that the researchers controlled for variables such as socioeconomic status and demographics (which were the first variables my own mind jumped to for a possible explanation), but I'd posit that, for example, kids at home in the afternoon watching TV and snacking can cross demographic and socioeconomic lines, so there may be more that can be investigated here. My kids usually get up in the morning and watch some TV while my husband and I get ready. After school, I'm often working or getting dinner together and whatnot, so my kids, again, are watching TV while I do that. I'm lucky enough to live in a neighborhood where I can send my older two outside on their bikes to play most of the time, but there are plenty of kids in all demographics who don't have that luxury. Learning more about the environment these children spend so much of their time in would be helpful.

- What's the difference between using computers and playing video games and watching TV?

Why is computer use not correlated with obesity but TV is? Is it because the child's brain is more actively engaged when playing a video game than when he's sitting passively and watching TV? What is the fundamental difference, here? I watch my 6-year-old play video games and he's jumping up and down and shouting and generally enjoying a full-body experience while he plays. That same 6-year-old will then sprawl on the couch like a lump while watching Ninjago or My Little Pony. There's a clear difference in physical engagement with the media. I feel strongly that this issue requires more study.

My kids watch a lot of TV, so this data concerns me. My kids also play video games and use the computer, so it's not just hours of TV every day, but they do watch a lot of straight-up TV. I know why and how they've ended up watching so much TV, and the ball is squarely in my court to make the change, if a change is needed. Now, while my oldest admittedly is struggling with his weight, my other three are of average weight for their height and age, and I don't think the reason for my oldest's being overweight is that he watches TV. Frankly, my younger three have watched more TV at a younger age than he did. Now, an anecdote is not data, and my family by itself is not statistically significant, but the results of these studies may still affect my parenting. As a parent who likes data and science and evidence-based philosophies, I really want to know more about this phenomenon so that I can make an informed decision about my children's screen use. If I am given a compelling reason as to why there is this correlation between weight and hours of TV, then I can decide if I need to cut way back on the screen use or if there are other factors I can control that will mitigate the effect of the TV itself.

I watched a lot of TV as a child. Even in the 1980s, researchers and doctors were becoming concerned with the strong association between hours in the front of the TV and weight. I was far from an overweight child despite my television watching habits. But there are many more options out there now than when I was a kid, and there are other screen-time possibilities besides simply switching on the tube and watching what's on. There are other ways to watch TV, such as on a tablet, computer, or phone. There are premium and subscription services. There are tablet games and phone games and PlayStations and XBoxes. "Screen time" doesn't just mean TV time anymore, and it's very important to sort out what's the most harmful and why and to figure out what, if anything, can be done to help improve the situation.

Sure, it's easy to say, "Watch less TV." But sometimes that's not as easy as it sounds.


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