Is eating in front of the TV really that bad for you?

By Jessica Brown of the BBC

With so many great shows and films to watch on television these days, it is tempting to catch up while eating. But is a TV dinner really a good idea?

The "TV dinner" doesn't have a great reputation, health-wise. The concept, which originated in the US in the early 20th century, conjures images of a processed meal packed with salt and additives, eaten balanced on your lap while sat on the sofa.

But what if you choose a different type of meal while in front of your favourite television series? You may think that having a colourful plate piled high with vegetables and wholegrains is a healthy habit. But does the simple act of eating it in front of the TV undo those virtuous choices?

There are some indications it might. Studies suggest that habitually eating while watching TV isn't good for us, no matter what we're eating. Here's why:

Distraction and memory

Scientists have long known that our wider environment plays a crucial role in our diets, and there's a wealth of research showing a link between watching TV and a higher risk of obesity, largely due to lower levels of exercise that come with such sedentary behaviour.

But watching TV may also be affecting how much we eat too. Being distracted is one of the leading theories behind why we might eat more while watching TV at the same time, says Monique Alblas, assistant professor of communication science at the University of Amsterdam.

This could be because, when we're sucked into a riveting plot, we have less attention available for eating so we're not aware of the bodily signals telling us we're full, which could lead to overeating. There's also research suggesting that we don't remember what we've eaten when we're consuming food front of the TV and struggle to accurately estimate the amount we've eaten, which could mean we eat more later on.

Alblas has found that people spend longer eating when they're watching TV at the same time.

She used already existing data collected by the Netherlands Institute for Social Research, for which people were asked to keep a diary of everything they did over a week, including eating and watching TV, and even what type of TV programmes they were watching.

When Alblas analysed the data, she found that the people spent longer eating when they were watching TV at the same time.

They also found that that the total time they spent eating was longer on days of concurrent TV-watching and eating at the same time, compared with days of eating without simultaneously watching TV, which she says suggests they didn't realise how much they were eating because they were distracted.

The findings themselves don't show that people ate more, necessarily, or what food they ate exactly, as the only thing they recorded was the length of time spent eating. Of course, as the results are self-reported, if people were losing themselves in a particularly good plot, they may have also just misremembered how long they had been eating for.

But, Alblas says, there's existing research showing that time spent eating is correlated to eating more calories.

"And lab research shows that distracted eating leads to increased food intake, so all the evidence combined suggests that distraction plays a major role when eating in front of the TV," she says.

Another reason we may eat more when watching TV is because food may not taste the same as it does when we're paying more attention to what we're eating. This is because we may not get as much satisfaction from food when we're distracted, says Floor van Meer, a data science researcher at Wageningen Food Safety Research in the Netherlands, who investigated distracted eating while working at the department of social, organisational and economic psychology of Leiden University in the Netherlands.

As a neuroscientist, van Meer has conducted numerous studies into the activity of the human brain when we're eating while distracted. In one study, in which participants were asked to memorise either a short or long number while eating, those who tried to memorise longer numbers reported that their food tasted less sweet.

Van Meer could also see less activity in their parts of the brain associated with taste perception.

"If you don't taste food in the same way, you might not be as satisfied, and you're more likely to snack sooner afterwards," she says.

(There is a flip side to this, says van Meer; TV may be a good way to get children to eat their vegetables if they don't like the taste of them.)

There's a theory that humans are always trying to meet a "hedonic goal", she says. This means we expect to get a certain amount of pleasure during any given day or activity, and if we don't achieve it, we seek it elsewhere. If a TV programme doesn't live up to expectations, you may eat more to compensate.

Our emotional state also plays a large role in our eating behaviours, and there is some research to suggest that we may choose less "hedonic" foods, such as chocolate or buttered popcorn, if watching something that makes us happy compared to something that makes us sad.

What are we eating while we watch TV?

Research has found that exposure to food adverts can also make people eat more generally. But what concerns researchers the most is the association between food adverts and eating ultra-processed foods (UFPs), which has been linked to obesity and other diseases, including heart disease.

"Evidence suggests that even brief exposure to food adverts can make children more likely to choose the advertised foods, with repeated exposure reinforcing this preference," says Fernanda Rauber, researcher at the Centre for Epidemiological Research in Nutrition and Health at the University of São Paulo in Brazil. She has found that children are more likely to eat UFPs than minimally processed food when watching TV.

This is partly because ultra-processed foods are often seen as more convenient to eat while watching TV, she says. But increased exposure to adverts for these types of foods has also been linked to increased consumption. The effects seem to be heightened if the children are already obese, perhaps because they have a heightened sensitivity to food adverts.

And while family meals are usually associated with eating more fruits and vegetables, Rauber has also found that children eat more ultra-processed food if they eat while watching TV with family.

"In this scenario, any perceived benefits of family meals observed in other research were overshadowed by the negative impact of having the television on during meals," Rauber says. "This underscores the complex interplay between dietary habits and environmental influences, and highlights the need for further research to understand these dynamics comprehensively."

The other sides of distraction

The relationship between watching TV and eating is complex, even when it comes to the effects of distraction alone. Research also suggests that being distracted can lead us to eating less - or not at all, says van Meer.

For example, van Meer says that some primary schools in the Netherlands have decided to shorten the school day and for the pupils to eat lunch while the teaching continues.

The teaching over lunch tends to be more passive, so they'll read to the students or put on an educational video, van Meer says. But, she adds, a lot of parents are finding that their children are going home at the end of the day with full lunchboxes, suggesting they were too distracted to eat as much.

This effect has also been found in research with adults. In one study, participants watched two episodes of the popular US sitcom Friends. One group watched the same episode twice, and the other group watched two different episodes. During the second episode, both groups were offered different snacks.

The researchers found that those who watched the same episode twice ate an extra 211 calories compared to the group that watched two different episodes. This may be because they were less distracted, says Dick Stevenson, professor of psychological sciences at Macquarie University in Sydney, Australia.

In other words, if the TV we're watching is engaging enough, we may forget to eat the food in front of us. But when TV is making us feel bored, we may eat more.

In another small study, participants watched a "boring" lecture about art on TV, or an "engaging" TV series - or nothing at all - and were offered low-calorie (grapes) and high-calorie (chocolate) snacks. The researchers found that the boring art lecture encouraged the participants to eat more overall, and the engaging TV show less, than the control group that didn't watch TV at all. In other words - the more bored they were, the more they ate. Interestingly, however, the main change in consumption was in the number of grapes they ate while the amount of chocolate stayed broadly the same.

So should we avoid eating while watching TV?

There are several theories underlying why we may eat more when we're eating in front of the TV. But reliable research in this area faces several challenges.

Researchers often rely on people's food diaries and tracking their own TV-watching behaviours, but people often underreport their consumption of unhealthy foods, says Rauber.

In Alblas's study at least, the participants she took data from were recording every activity in their daily lives, so they won't have been particularly conscious of recording eating or TV watching.

Researchers also study people eating and watching TV in laboratory settings. But the nature of watching TV means we're usually relaxing at home, so trying to recreate this in a lab can be challenging.

"Direct observation methods may introduce the bias of behaviour change, where participants modify their eating habits knowing they are being observed," Rauber says.

There needs more research in a real-life settings, Alblas argues, because our eating behaviours - and what influences them - are so complex.

"We know some of the ways TV influences food intake, but there are many pathways and things we don't know that need to be understood better," she says.

How much TV influences our food intake depends on many factors, including the type of content we're watching, says Stevenson. It can alter our mood, but also influence us in unconscious ways - such as if a character is eating on screen, we may also feel compelled to eat along with them.

The pace of the programme can make a difference too - action movies can induce us to eat more than watching an interview show, according to one study.

And of course, the food we have to hand and how palatable it is is also important, alongside how impulsive we are with food.

Also, distraction is complex, too. Watching TV may be no more distracting - and therefore no more likely to make us eat more - compared to other activities we do while eating. One analysis of studies, for example, found that there's little evidence suggesting we eat more when watching TV compared to doing other things, such as reading, playing video games or eating with friends.

Research suggests that our eating behaviour is complicated, and almost impossible to fully untangle. Certainly, there is more to the "TV dinner" than simply processed, high-fat, high-salt convenience foods. So if you are sitting down to have a healthier option, it might be worth considering whether you really want to reach for that remote control after all.

- This story was first published by theBBC.