Watching Your Weight

The average American spends more than 150 hours a month in front of the television—that’s six days—and never mind other sedentary hours we spend with computers or mobile devices. As our screen time has exploded, so has the national waistline. Two thirds of adults are overweight, and childhood obesity has more than doubled in the last 20 years.

One reason why obesity may be on the rise is that people who watch a lot of television may eat more, particularly pizza, soda and other fast foods, according to a recent Tufts study that evaluated 30 years of research linking TV viewing with weight gain. The paper, authored by four students and their advisor, Robin Kanarek, interim dean of the Friedman School of Nutrition Science and Policy, was published online in the June 4 edition of Physiology and Behavior.

The link between watching TV and unhealthy eating is not surprising. Consider one fact: the food industry spends $1 billion annually on advertising that targets children and teenagers, according to the Tufts analysis. The authors point to a 2010 study conducted by public health researchers at Armstrong Atlantic State University in Savannah, Ga. It calculated that if children chowed down on the foods promoted by the advertising aimed at them, they would be consuming 25 times the sugar and 20 times the fat—but less than half the fruits and vegetables—recommended by current dietary guidelines.

Kanarek and the students—Rebecca Boulos, N13; Emily Vikre, N08, N13; Sophie Oppenheimer, N11, MPH11; and Hannah Chang, A10—also presented  research indicating that television can shape societal views about overweight and obese people. They found evidence that excess weight is heavily stigmatized on television, often used as shorthand to indicate a character is evil, unattractive, incompetent, not to be taken seriously or simply greedy. At the same time, fat people are underrepresented. Only 14 percent of female characters on TV are overweight, compared with more than a third of American women.

Kanarek, a psychologist who studies nutrition and behavior, and Boulos, a USDA doctoral fellow in obesity at the John Hancock Research Center on Physical Activity, Nutrition, and Obesity Prevention at the Friedman School, talked with Tufts Now about how our TV habits might be affecting our health.

Tufts Now: How does TV make us fat? Couldn’t the same be said for any sedentary activity, such as reading or sitting at work all day?

Rebecca Boulos: The perception is that if you’re watching TV, you’re not exercising, and it really isn’t that simple. TV plays a role not just in energy expenditure, but also in energy intake. Many people eat particularly high-calorie foods while they’re watching TV. They are also more prone to eating the foods they see advertised on TV, and those are energy-dense ones. So it’s not just that they’re watching an hour of TV instead of taking an hour-long walk or bike ride. Ultimately, that choice to watch TV is a triple whammy: you’re moving less, you’re eating more, and your perceptions of what is normal are being altered.

Robin Kanarek: We were interested in things like product placement and how often people on TV are seen eating. It’s not in the paper we just published, but I did a very rough calculation watching a few situation comedies, The Middle, Friends and How I Met Your Mother. The characters on Friends spend a large amount of time either in the coffee shop or in an apartment, and they are frequently eating. On How I Met Your Mother, they’re in a bar, and they’re often eating hamburgers, cheeseburgers and French fries. In one episode of The Middle, I counted 18 occasions when characters were eating, with the food of choice being either pizza, popcorn or sweetened cereal. I don’t like to say those foods are unhealthy, but the characters were never eating anything most people would call healthy food.

What about reality shows—do they portray weight issues more realistically than children’s shows and situation comedies?

Kanarek: A paper that came out after ours looked at the effects of the weight-loss shows, like The Biggest Loser. Weight-loss shows seem like such a great idea, but it’s not realistic for most individuals to have a personal trainer come regularly to their homes, or to live on a weight-loss farm for several months. I think it’s interesting because very few people have looked at whether weight-loss programs ultimately increase or decrease peoples’ desire to diet. What happens, for instance, if an individual goes on a diet but doesn’t experience the same kind of miraculous weight loss as shown on television?

Boulos: The news media can also influence society’s understanding of the obesity epidemic. It typically oversimplifies the complexity of the situation by emphasizing the role of the individual, rather than environmental and social causes. This can lead people to blame individuals rather than look at more systemic problems and social patterns, such as our cultural approach to time management, the role of advertising and marketing and the kinds of food we serve in schools.

One thing we hadn’t thought much about until we started working on this was the role of cooking shows and how they influence viewers’ perceptions of food preparation. There’s a term we came across called “food porn.” Effectively, people watch others prepare food and imagine eating it, but don’t actually intend to prepare or eat the foods themselves. This can set unrealistic expectations about what it means to cook at home, which can deter people from preparing a meal instead of ordering take-out. This idea has been covered more in popular media, but has been less explored in more rigorous, large-scale research studies.

It doesn’t seem like most people are willing to curb their TV watching. How can we break the link between viewing habits and obesity?

Kanarek: We have to be realistic. We are never going to go back to the ’50s, when the mother was at home all day, and kids came home from school and played outside. People just have to be educated. I don’t think people realize how much TV they watch. In some households, the TV is on almost all the time, and many children start watching TV when they’re less than a year old. People don’t even have to be in the home anymore. With iPads, people can watch TV or a movie anywhere they want.

Speaking of iPads, has there been any research on how viewing content on mobile devices may impact obesity?

Boulos: I really think it can go both directions. People might be watching TV or movies on their tablets instead of playing or exercising. But mobile devices can also serve as motivation. People can upload runs and bike rides with other users on sites such as mapmyrun.com and mapmyride.com. They can share their activities on Facebook and get social support that way, too. They can also download apps for their smartphones that let them enter which foods they’ve eaten and which physical activities they’ve done. There is a little research that supports text messages as a way to encourage weight loss. So there is variability in the ways in which people use their mobile devices, and potential for both positive and negative influences on obesity. This is another area in which we could use more research.

Jacqueline Mitchell can be reached at jacqueline.mitchell@tufts.edu.