As 15 people nervously walk into a lab, they’re greeted by researchers at Liverpool John Moores University. They are about to hear what they will put their body – and taste buds – through over the next two weeks.
They’re helping researchers understand the impact that frequently eating takeaways has on health – and they’re going to eat them twice a day for a fortnight. We see the experiment play out in BBC One documentary, The Truth About Takeaways.
This is just one of several experiments on the show. The cameras follow journalist Nikki Fox as she speaks to experts from university research labs all around the country.
So how were those taking part affected, what do the results tell us about the impact of a takeaway-heavy diet, and which is the worst takeaway for your health?
Why two takeaways a day?
As a nation, we consume a LOT of fast food. In fact, in a Food Standards Agency survey, 27 percent of respondents reported eating a takeaway once a week. Further research highlights that one in six 16–20-year-olds eat fast food twice a day.
“The purpose of the (Liverpool John Moores) study was to assess the response of two takeaway meals per day with respect to health markers”, explains Dr Ian G. Davies, Reader in Nutritional Science at the university, who led the experiment.
“The consumption of takeaway (and other out of home) food has increased in the UK (especially in the young and adolescents) over the past few years, and there is limited experimental evidence on how this affects obesity and risk of certain metabolic and cardiovascular diseases. We tested this on 15 participants initially, with 12 who completed the study.”
On the menu in the experiment were kebabs, fried chicken, burgers, pizza, fish and chips, Indian, and Chinese food. Why these? Because they are said to be the most popular takeaways in Britain.
How the participants felt by the end of the experiment
The participants kept video diaries, as well as having medical examinations along the way. And we see that while they start the challenge with gusto, as the two weeks progress, it becomes harder and harder for them to maintain the diet.
Some of the participants struggle with poor sleep, feelings of sluggishness and lacking motivation to carry out their normal, everyday tasks.
The impact on their short-term health
“Overall, the majority gained weight, which was a gain in body fat for most of the participants. With respect to cardiovascular disease markers, plasma triglycerides (the concentration of fat in the blood) increased for more than half the participants. This is a marker of increased cardiovascular disease risk. Cholesterol levels, both ‘good’ and ‘bad’, showed approximately half the participants increased and the other half decreased, with no overall significant difference before and after the two weeks.”
The good news for the participants is that they were unlikely to experience long-term health issues if they reverted to their usual diet.
“Some individuals increased body mass and risk markers, but on return to their normal diet, this would likely be reversed over a short time period.”
If the diet was maintained, however…
At the end of the experiment, the participants were pleased they would be able to return to their normal diet. But if they decided to maintain a two-a-day takeaway habit over months and years it could have serious repercussions on their health.
“I would predict negative health consequences in relation to body weight and cardiovascular disease risk… When looking at the totality of evidence from other cross-sectional studies that investigate fast food and takeaway intake compared to body weight, and cardiovascular risk markers, there is a significant correlation showing about two takeaways/fast food meals per week is associated with increased body weight and various cardiovascular risk markers”, says Dr Davies.
Is pizza really the ‘worst’ takeaway for you?
Within the programme we see – in another experiment carried out by University of Reading Professor Gunter Kuhnle – that when compared to five other takeaways (three big brands and three high-street favourites), eating a whole pizza is revealed to have the most calories and fat (although the takeaway outlet recommends only eating three slices).
This is backed up by Dr Davies, who has been involved with further research that examines the nutritional composition of various takeaways. It supports the claim that pizzas are the ‘worst’ takeaway for your health, but there is a big disclaimer: every takeaway is different.
“In terms of the average amount of salt, fat and energy density, then yes, from our work pizza comes out as the highest compared to other takeaway food”, says Dr Davies.
“It is important to note though that there is a very large amount of variability between and within takeaway meals from one establishment to another. For example, some Chinese meals are very high in salt and sugar, whereas kebabs are high in trans fats. So it is quite difficult to state which takeaway meal is the ‘worst’. One particular meal may differ in salt, fat and sugar between different outlets, which makes labelling the ‘worst’ even more difficult”, he continues.
And don’t forget portion size
“From our research, the median average results show that pizza is highest in energy density, followed by English, kebabs, Indian and Chinese. But this is energy per 100g”, explains Dr Davies.
“When considering portion size, the pattern is similar, but kebabs tend to be the smallest portion and therefore have less overall energy. Pizza and Chinese meals tend to be the highest in salt, and pizza and Indian highest in total sugars. For fat, and especially saturated fat, it shows pizza and English meals to be the highest and Chinese the lowest. Kebabs are highest in trans fats”, he continues.
This is something Professor Kuhnle discovered in his experiment for the programme. The branded chicken and chips came out as the least harmful – nutritionally speaking – compared to the other takeaways, but was all as it seemed? He says it was was “mainly due to the small portion size”.
Brands and chains v local takeaways
While the branded chicken and chips came out healthiest in Professor Kuhnle’s research, another big brand came out as unhealthiest. Is there any evidence that suggests you’ll get fewer calories and less fat from bigger brand takeaways than from an independent outlet?
“The main difference between chain restaurants and independent takeaways is regulation”, says Dr Davies. “The chains produce nutritional labelling, but the independents would find this difficult. The independents tend to have higher energy content compared to the chains.”
So would the Liverpool-based scientist like to see nutrition labelling on all takeaway food? “While this would be a step in the right direction (and may reduce energy content). the independent takeaways would find it difficult due to the variability in cooking practices. Perhaps showing the averages from published research may be a good halfway house. However, any labelling practice like this would need to be researched to investigate consumer behaviour.”
Apps are changing the face of takeaways
When surveys are carried out in the future, will the most popular takeaways be different to the ones we see now? There are plenty of food delivery apps that are starting to change our dining habits, not only in terms of what we eat but also where we eat it.
“Just Eat’s annual report for the first half of 2019 reported a 21 percent increase in orders and 21 million new customers, so it isn’t surprising that our research also suggests that the frequency of takeaways ordered is expected to increase in the future”, says Amelia Brophy, Head of UK Data Products at YouGov. She believes that with the rise in people using food delivery apps, there will be fewer of us having our traditional ‘meal out’, well… out.
“In line with declining spending on the high street, Brits in general aren’t spending as much on going out to restaurants for food”, she says.
If we want to avoid health issues associated with frequently eating takeaways, we may well need to adjust our menu and portion size expectations. Dr Davies adds: “Our unpublished evidence shows about 27 percent of the population (from a relatively large Merseyside dataset) consumes a takeaway about one or two times per week, which is in line with previous work from the Food Standards Agency. At twice per week, the published evidence shows association with obesity, Type 2 diabetes risk and cardiovascular disease risk. Various strategies are needed to reduce this risk, such as reformulation of takeaway food (reducing salt, sugar, fat), offering smaller portions sizes and implementation of various policies (such as fewer establishments close to schools). Importantly, any of these strategies needs a strong research focus to establish the effect on consumer consumption behaviour.”
Watch The Truth About Takeaways on Thursday, February 27 at 8pm on BBC One.
