Tuesday September 2 2014
Participants watched “The Island”, an action-science fiction film
“Couch potatoes captivated by fast-paced action films eat far more than those watching more sedate programmes,” The Independent reports.
A small US study found that people snacked more when watching action-packed movies.
The study took 94 US student volunteers and randomly assigned them in groups to watch 20 minutes of either the action film “The Island” with sound, the same film without sound or “Charlie Rose”, a long-running American talk show.
They were provided with unlimited snacks of M&Ms, cookies, carrots and grapes.
People watching the action film with sound ate 65% more calories than those watching the talk show.
Researchers discussed the hypothesis that the frequent visual and audio variations in “The Island” (a style of filming that director Michael Bay, best known for the "Transformers" films, has become notorious for) may be distracting. This means participants may have been unaware of how much they were snacking.
However, this does not prove that action films make you fat. The study appeared to allow students to gather themselves into groups before being assigned to what they would watch. This could have meant the groups were not adjusted for factors such as food preferences, physical activity or when the students had last eaten, which could all have influenced results.
The study does remind us, however, that we need to pay attention to what we eat, including food we consume while distracted, as it all counts towards our daily calorie intake.
Where did the story come from?
The study was carried out by researchers from Cornell University in New York and Vanderbilt University in Nashville. It was funded by Cornell University.
The study was published in the peer-reviewed medical journal JAMA Internal Medicine.
The UK media reported the story accurately, but did not highlight any of its weaknesses. However, The Independent did helpfully publish advice from England’s Chief Medical Officer that people should do a minimum of 150 minutes (2.5 hours) of moderate activity a week.
What kind of research was this?
This was a randomised controlled trial that aimed to see if people ate more snacks depending on the type of TV content they were watching.
While randomising participants is the best way to get groups that are balanced in their characteristics, this study only gave limited details of how this was done. This makes it difficult to know exactly how well the randomisation worked, and if the groups were truly balanced.
What did the research involve?
The researchers recruited 94 undergraduate students, gathered in groups of up to 20 people, then randomly assigned them to watch TV for 20 minutes, which was either:
- an excerpt from action movie “The Island”
- the same excerpt from “The Island”, but without any sound
- an interview programme (talk show) called “Charlie Rose” – a celebrity focused talk show
During the 20 minutes, four snacks were made available: M&Ms, cookies, carrots and grapes. They were allowed to eat as much of them as they wanted. The amount of snacking per person was calculated by weighing the snacks before and after the 20 minute programme.
The researchers then analysed the results by type of TV show and sex of the participant.
What were the basic results?
Participants watching the action film with sound ate 98 more grams (g) of food than those watching a talk show (206.5g versus 104.3g). This equated to 65% more calories (kcal) consumed in the action film with sound group (354.1kcal versus 214.6kcal).
Those watching the action film without sound also ate significantly more snacks than people watching the talk show – 36% more grams of food (142.1g versus 104.3g) and 46% more calories (314.5kcal versus 214.6kcal).
Males ate more than females in all three groups.
How did the researchers interpret the results?
The researchers concluded that “more distracting TV content appears to increase food consumption: action and sound variation are bad for one’s diet”. They suggest that people should either avoid snacking when watching distracting TV or use “proportioned quantities to avoid overeating”.
This study appears to indicate that the type of TV programme a person watches can influence how many calories are consumed as snacks. However, little information was provided about the methods and findings of this study, which makes it difficult to be certain how well it was performed and, therefore, how robust the results are.
The potential issues with the study that could affect interpretation of the results seen include:
- The participants were not randomly assigned to the different groups individually – instead they “gathered” into groups, and then these groups were randomised. This might mean that friends with similar likes and preferences gathered together and ended up in the same group. These self-selected groupings may have differed in their characteristics (e.g. gender, body mass index (BMI), physical activity or socioeconomic status), and these differences could affect results.
- It is not clear whether the same number of people were exposed to each scenario, as the number of people in the groups was not reported.
- No information was provided on which snacks the participants chose to eat, only the overall quantity in grams and calories. While it is tempting to assume that the people eating more calories were eating the unhealthier food, we don’t know whether this was the case. Indeed, the difference between the average least amount of snacks and the highest average amount was 100g and 140kcal – this suggests that the difference was not entirely of unhealthy food, as 100g of M&Ms contains more than 544kcal.
- It is unclear what time of day the programmes were watched or whether they were all watched at the same time of day. Time of viewing could have a large effect on snacking, depending on the timing in relation to meals.
- The students eating the most snacks may have had a higher physical requirement for food due to their level of sport or usual activities. The study also didn’t look at whether the people who ate more in snacks compensated for this in their later meals.
- The study was conducted on students, and their behaviour may not be representative of the population at large.
In conclusion, this study in isolation doesn’t prove that watching certain TV programmes or films makes you fat. However, it does act as a reminder that we should pay attention to what we eat, including food we consume while distracted, as it all part of our calorie intake.
It is still recommended that you aim for at least 150 minutes (2.5 hours) of moderate physical activity each week, as well as eating a healthy, balanced diet.
If you are trying to lose weight, it might be a good idea to remove snacks from situations where you may get distracted – whether that is at home watching TV or at the cinema.
Only eating in a set location, such as your kitchen or dining room, can be a good way of staying mindful of how much you are actually eating; even a few extra snacks every night can quickly add up.
There are, however, a range of 100 calories or less snacks you can try, that shouldn’t put you over your daily calorie intake.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.