TV, video games, or Internet: Which activity makes teenagers fat?

I talk a lot about the importance of context in understanding science. The results of one, single research paper do not tell you everything you need to know on a given subject. Instead, you have to look at how those results fit into the big picture. How do they compare to the results of other studies on the same subject? Have the results been independently verified? How do the specific experiments being done influence what you can and cannot say about the results? What questions aren't answered by the study, and what new questions does it bring up?

You should be thinking about that every time you see anybody talk about the results of a single, new study. Without context, you get situations like this one, described by Travis Saunders on the Obesity Panacea blog:

Earlier this year my friend and colleague Valerie Carson published an interesting paper examining the health impact of various types of sedentary behaviour in a sample of 2500 children and adolescents. They created a clustered risk score (CRS) which took into account a child’s waist circumference, blood pressure, cholesterol, and inflammation, and then examined whether it was associated with 3 different measures of sedentary behaviour – accelerometry (an objective measure of movement), self-reported TV watching, and self-reported computer use.

Here is what they found (emphasis mine): For types of sedentary behavior, high TV use, but not high computer use, was a predictor of high CRS after adjustment for MVPA and other confounders. Here is what the Daily Mail had to say: Watching TV most damaging pastime for inactive children, increasing risk of heart disease.

Last month, our group in Ottawa published another paper (led by Dr Gary Goldfield) looking at different types of sedentary behaviour and heart disease risk factors in a cohort of overweight and obese teens (in contrast, the earlier study was on a sample of nationally representative youth). Interestingly, we found that neither TV time nor computer time was associated with increased risk in this group - in our dataset it was video games that were by far the most important sedentary behaviour.

Why is this a problem? Put yourself in the shoes of someone who just read the Daily Mail article, and who now believes that TV viewing is the single most damaging sedentary behaviour for kids to engage in. What reaction are you going to have when you read a similar article about our new study, suggesting that TV viewing and computer use aren’t important at all, but that video games are actually “the most damaging activity an inactive child can indulge in”?

As the source of this problem, Saunders rightly calls out journalists for pushing every individual study as a "GROUNDBREAKING NEW FINDING". It is, unfortunately, rare to find TV and newspaper coverage that treats new studies in context, rather than as the final word. But to that, I'd add university PR people. The sad truth is, with newspaper layoffs, many of the people writing about science aren't specialists. They cover city council one day, school board the next, and a new research finding after that. The press releases they get (and I know, because I get those press releases, too) push GROUNDBREAKING NEW FINDINGS not research that fits into a larger context. It's the journalists job to know better. But it's also the university's job to not manipulate journalists.


  1. TV, internet and video games are a symptom, not the cause.

    With all the fear mongering telling parents that their 14 year olds will be abducted off a bus by terrorists if they travel without parents or that if you don’t school-bus or drive your kid to school you are putting them in grave danger from strangers/friends/meteorites etc you end up looking like a bad parent if you let your kid play on the street – so *inside* the kids go in order to keep them *safe*.

    But as any parent knows, put enough bored kids inside a house for long enough and you will be driven crazy – so some parents get movies, video games and computers as a substitute for the outdoor play they should be getting.

    What the article should be about is how the media and other adults shame parents into keeping their kids indoors for fear of looking like bad parents, which results in endangering them with inactivity.

        1. Maybe people eat more than they did previously. That’s distinctly possible, but I don’t know one way or the other itself.

          One thing I DO know is that since the 70s (the time N M brings up), outdoor recreation for young people has all but disappeared.

          There are a lot of factors.

          Number one is a probably general distrust in people at large. Kids (and parents) are taught to fear everyone and everything, and that the only safe places are in their own homes or their locked down, fenced off schools.

          Even when kids and parents are willing to put a bit of trust in the rest of the world, often there isn’t much in the way of available play resources. Urban sprawl means you need a car to go anywhere in many places in the US, which means the parents have to make the time (and find the gas money) to drive the kids anywhere. Even then, you need somewhere to go that doesn’t cost money.  Public parks, pools, libraries, beaches, and the like are often neglected for the sake of local budget balancing. Even when they aren’t, they’re often underutilized – and nothing is less appealing than an empty park or beach to wander around by yourself.

          And neighborhoods have changed from communities of people living next to each other into neatly ordered isolation unit groupings. You might be the most trusting person in the world but if you live in on a street which is always empty, where windows are always shuttered and no one answers their doors, you don’t have a neighborhood. It’s even worse in gated “communities” – the isolation is not just expected, it’s often institutionalized and enforced. I’ve had the rent-a-cops called on me by an overzealous third party for entering my next door neighbor’s open garage to return a borrowed hex wrench WHILE HE WAS IN THE GARAGE WITH ME.

          This is more than just “kids are greedy hogs and parents are lazy bastards”. It’s a cultural shift which has indelibly changed the very infrastructure of outdoor play. The cost-benefit ratio has been changed. It’s much easier and cheaper to buy a computer or a video game console and play at home than it is to find an enjoyable way to play outside. Video game worlds are often very empowering, challenging, and compelling – dead neighborhoods and distrustful people are far less so.

  2. Maggie has it right when she blames university PR people for the hyperbole. I know it’s their job to make the research of their institutions seem cool, but not every result *is* groundbreaking. Nor should it be.

  3. Hear Hear, Maggie!

    I once spent hours trying to track down the basis for a news report saying that a particular disease could be treated with a particular nutrient.  I found the original paper, and it was about cellular mechanisms – it never mentioned the disease.  The actual source was a news conference called by the university’s PR department where one of the authors mentioned two or three diseases to put the mechanism in context.  The university’s press release slapped one of those diseases on the headline of the release – and the rest is misinformation history!

  4. Dear Researchers, I’ll give you a hint. The form of entertainment that makes teenagers fat is the one they can eat.

  5. I’m a journal editor, and frankly, we do this, too. Journal editors face some perverse incentives with the misuse of the impact factor and over-emphasis on mainstream media coverage. It’s in our journal’s interest to push findings from individual articles. 

  6. Just a crazy hairbrained theory here, but I suspect that fatness occurs when (calories eaten) > (calories burned).

  7. I honestly don’t get why researchers would want to bother looking into which types of “sedentary behavior” are more prone to make people fat.

    Forgive the obvious, but they’re all SEDENTARY BEHAVIOR.  If you eat too much, eat bad food, and don’t exercise — and instead opt to sit around on your ass for hours on end, you’re going to get fat.  Does it matter what you’re doing when you’re sitting down?

    This sounds like the half-baked sort of study that one of the less-achieving students in school would do, simply to fulfill a course requirement.

    1. Hi, have you met science? It turns out that what we call “common sense” often doesn’t match up with reality real well. That’s why people do studies like this. Not because they’re “less achieving students”. 

    2. Understanding sedentary behavior is critical to understanding a broad range of developmental and health issues, not just obesity. There’s a large and growing body of evidence on sedentary behavior, and the good data are indeed being drawn from rigorous longitudinal studies conducted by senior investigators. 

      It’s important to have an intimate understanding of sedentary behavior in order to design interventions that will be truly effective in minimizing the negative correlates of such behavior. See, for instance, Biddle et al.’s recent meta-analysis in the British Journal of Sports Medicine.

    3. Yes, Jonathan, lack of physical activity contributes to obesity, so any of these sedentary activities can contribute to obesity. The easy solution has been known for some time – put down your fork and go for a walk.

      But these studies asked the exact same question that you did – “Does it matter what you’re doing when you’re sitting down?” We might speculate (hypothesize) that television, computer use and video games might have different effects on heart rate, types of mental processes, and other outcomes the could affect our metabolism. If there were a huge difference between television and video games (there isn’t), the scientists would probably want to know 1) why? and 2) if we get kids to exercise and cut out television but not video games, does it make kids lose more weight?

      Some very common sense recommendations can come out of these kinds of research when 1) we don’t dismiss the research without better understanding it and 2) don’t go all crazy calling it a GROUNDBREAKING FINDING.

  8. My dear father, a man of great intelligence and many degrees is in the unfortunate position of trying to manage his wife’s Alzheimer’s. Since I am an above average computer and science maven and my best friend is an MD, he often comes to us to discuss GROUNDBREAKING STUDIES. It’s not groundbreaking – it’s heartbreaking. For all my Dad’s smarts, hope leaves him vulnerable to the misplaced optimism of bad science writing.

  9. I don’t work for a large research university, but I do work in PR for a small baccalaureate college and have written and edited a few press releases about research. It seems no matter how carefully we word a release to be accurate and satisfy the researchers’ wishes to not over state their findings, much of the context and complexity gets stripped out in the final article that goes to press. That’s still better than the televised news segments though. Even the best TV reports have a tendency to be sensationalized without a care for accuracy. 

    Research reporting is really a funnel that removes accuracy. It starts with the scientists themselves who are often incapable of explaining their findings to an audience who do not share their academic backgrounds–even PhDs from other fields often don’t understand the jargon that has become invisibly pervasive in a researcher’s mental lexicon. 

    Then the PR person comes in to interview and, in the process of sending drafts back and forth for the scientist to approve, has to have arguments about whether an article for a general audience can say, “plantain,” or must instead say, “plantago major” in every reference (example based on a true story). By the time the PR person and scientist have hammered out the findings into something that the PR person would be capable of understanding and wanting to read, already some the scientist is likely not completely comfortable with, but is at least truthful if not as precise as they would like. 

    Then the journalist gets the approved release, and starts over, usually re-interviewing the researcher, but without the benefit of a long term relationship or a soft deadline. Having little to no advanced science education themselves, what the journalist thinks they hear is often not what the scientist is saying, and more inaccuracy is introduced into the story.

    I could go on, but my point is, PR and journalists need to learn science better, yes. Also, scientists need to learn communication so they are capable of discussing their findings with people outside their field. 

  10. Partially hydrogenated soybean oil & high-fructose corn syrup are the ingredients of obesity. These additives weren’t around back in the 60s and early 70s. Funny, when kids were sitting around playing chess, Monopoly, painting, reading, listening to music, nobody talked about these activities making them fat. Throw a TV in the mix, and the story changes.

  11. Just for the sake of argument/conversation, if the question was reworded to ask which the worst was.. it could be said that video games have the least negative impact as they don’t really leave hands free for filling up on unneccesary eating of foods good and bad while sitting idle, staring at the zombietube

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