from the School for Policy Studies
By James Garbutt
When it comes to managing type 2 diabetes, there are lots of extreme diets out there with passionate advocates. Avoid carbs! Reduce fat! Restrict calories! However, researching the effects of diet on health in terms of single nutrient changes can be misleading. (more…)
Ensuring that that our research considers and promotes equality, diversity and inclusion is central to the work we do at the School for Policy Studies. Working in partnership with communities and stake holders to identify research questions that matter and ensuring that studies are co-produced wherever possible helps achieve these aims. This series of blogs posts looks at some of the ways what we research and how we go about it incorporates EDI principles.
In this post, Kate Bowen-Viner (Social Policy PhD student) explores how research in the Centre for Exercise, Nutrition and Health is helping to make physical activity guidelines more inclusive. (more…)
Written by Dr Laura Johnson and Dr Zoi Toumpakari
Family life has been transformed by lockdown. Since schools closed on 23rd March many families have had to create classrooms at home and juggle home-schooling with home working. But what has happened to school food at home? Are packed lunches still the norm or are family meals now the dish of the day?
Campaigners like the Food Foundation (@Food_Foundation) have already identified the most vulnerable children and are working hard to ensure that free-school meals are maintained for 18% of families with children eligible. Under half of these families have been given vouchers to buy food, another third has had food prepared for collection or delivery by schools, so provision, to some extent, has continued. But worryingly a third have not had anything. Furthermore, out of necessity food provided is often highly processed to ensure it lasts for a week or more at a time, suggesting that compared with food served in canteens, where school food standards apply, food quality may have dropped. But what about the other 82% families? Are meals worse across the board? Or is it possible that for many children lockdown lunches are a healthier option than the norm?
According to a YouGov poll in April, over half of households haven’t noticed a change in what they eat, but 1 in 3 have reported cooking from scratch more often; 1 in 5 think their diets are healthier since lockdown but 2 in 5 think they are eating more. Straw polls of families we know have reported diverse reactions. Some are more aware of what their children eat, have more control, are providing more fruit or eating meals as a family. Others have been fending off relentless biscuit requests (not always successfully). For some kids it’s meant a switch from cooked school dinners to more packed lunch type fare at home. But is that a problem? What do we know about school food pre-COVID19?
A review of studies up to 2007 comparing the nutritional quality of packed lunches to school dinners found that more energy, sugar, saturated fat and salt was in packed lunches. Back then both school dinners and packed lunches were pretty poor. However, school food standards have been in place in England since 2006 to raise the nutritional quality of food provided by schools. Around the world, as in England, the introduction of school food standards have generally improved the quality of meals provided in schools. Although intakes of vegetables and nutrients like fibre and iron still need attention, fruit intake is up, fat intakes are lower (especially saturated fat) and less salt is being consumed from school canteens.
Improvements in school-meals is great news, a real win for public health, but now the gap in the quality between school dinners and food brought from home has widened and the spotlight is firmly on packed lunches as a key area for action. Food from home still makes up 40% of meals eaten in UK schools. Recent times have seen small changes in how often sweets and how much sugary drinks are packed in lunches, but protein is lower and vegetables remain sparse, at just half a portion a day. Multiple interventions aiming to change packed lunch quality have been tested but with little success to date.
Our work on the National Diet and Nutrition Survey has used the detailed reports of what teenagers ate over 4 days to identify the key differences between meals at home vs. school. We found that most eating (two thirds) happens at home, and only 1 in 8 meals are consumed at school. Nearly 3 out of 4 school eating occasions included foods high in fat and sugar, compared with 2 out of 3 meals at home. We found that when eating at school, foods high in fat and sugar were not only eaten more often but also in larger amounts. We estimated that teenagers ate an extra 59 calories of foods high in fat and sugar in school-based meals compared with a similar meal at home, the equivalent of half a bag of Wotsits.
The kinds of foods high in fat and sugar eaten at school are similar to those eaten at home, including crisps and savoury snacks, biscuits, sugary drinks, cakes and chocolate. But there were some key differences between eating at home and school. Predictably, eating at school occurred primarily at lunchtime (about 50% of all eating) but it was also common in the morning too (40% of eating). In contrast, meals at home happen throughout the day, with around 50% occurring after 5pm (i.e. dinner time). Eating at school is more often with friends whereas at home eating is as likely to be alone (33%) as it is with family (39%).
We also went to talk with teenagers directly about what they thought influences their eating. For most teens, food choices when away from home are a result of many different factors working together. But they told us that they enjoyed eating most when they were with their friends, one said “I tend to prefer to eat at school because I’m with my friends and it’s more sociable really than with my family.”. Social drivers are clearly important. Therefore, creating social school environments that enable and actively promote healthy choices could be an element of achieving positive change in school food future. An interesting challenge in our new socially-distant world.
Many schools are opening up more widely today, what might the lifting of lockdown mean for children’s diets? Some schools, to prevent spreading the coronavirus, have banned packed lunches. In other schools, ensuring a safe school food service is a concern so packed lunches are mandated. Social distancing may limit the kind of interactions kids used to enjoy about lunch times at school, will that affect what they eat now? Times are changing fast, new normals are being created and this may be an opportunity, in the longer-term, to reset the system for the better.
About the authors
Written by Dr Laura Johnson and Dr Zoi Toumpakari, Centre for Exercise, Nutrition and Health Sciences in the School for Policy Studies at the University of Bristol. Dr Johnson is a member of the GENIUS network, funded by the UK prevention research partnership, which aims to build a community of school staff, policymakers, food providers and researchers to generate fresh insights into the challenge of ensuring healthy food in schools and reducing inequalities. Follow us in twitter @GeniusSFN
Dr Simon Sebire, Centre for Exercise, Nutrition and Health Sciences, reflects on the success of the physical activity initiative, The Daily Mile.
Ten days ago I had the pleasure of being involved in the launch of The Daily Mile in Guernsey. The Daily Mile has been taken on by most schools on the Island in the last 9 months and Thursday 24th June was a celebration of the work here to date. Elaine Wyllie, the founder of The Daily Mile and John, Elaine’s husband, were in Guernsey to support the launch. This included a tour of Daily Miles at various schools around the island, a celebration mile and lunch and a special mile for some pupils around the beautiful Government House (the residence of the Lieutenant-Governor, the Crown’s personal representative in the Bailiwick of Guernsey).
It was whilst walking the mile around the Government House grounds (being lapped by happy, rosy-cheeked children in the process) that Elaine and I began discussing how my research on people’s motivation for physical activity and developing interventions could help explain why children and schools in Guernsey and around the world seem so taken by The Daily mile phenomenon.
Elaine explained her take on this by beginning the following conversation:
Elaine: Think of a happy memory you had as a child, but don’t tell me what it is.
Me: (thinking…)
Elaine: Now tell me, were you inside or outside?
Me: Outside
Elaine: Were you on your own or with others?
Me: With others
Elaine: Were you in the supervision of adults?
Me: Sort of … at a distance
(By the way, my happy memory was of when I was 7 or 8, a hot summer day, building a sand boat with family and friends to sit in as the tide rose up Port Grat beach in Guernsey. I was outside, with other children and parents were involved sporadically, but letting us play freely.)
In identifying a happy memory, Elaine had just revealed some of the core principles of The Daily Mile. These include a focus on having fun, being non-competitive, being outside and in nature, connecting with other pupils/teachers, being a simple intervention, being fully inclusive and owned by the children (i.e., jog or run at their own pace).
These core principles chime with the fundamental elements of much of my research into physical activity motivation. Using a psychological framework called Self-Determination Theory (or SDT) I have studied the foundations of and outcomes linked with high quality motivation for physical activity in children and adults. According to this approach, a person’s motivation is deemed to be high quality when it is autonomous, in other words when motivation stems from the enjoyment of being active, the satisfaction one gets from being active (or doing a mile), a feeling that being active is in harmony with a person’s sense of who they are, or that being active brings them personally valued benefits (e.g., meeting pupils in other year groups or getting fitter). People have these kinds of motivation for being active when they experience SDT’s core principles; Autonomy, Belonging and Competence (A, B, C).
Autonomy: Feelings of volition, freedom, choice, ownership and empowerment
Belonging: Feeling strong connections with others, included, understood and respected
Competence: Feeling capable, able to master a skill or task.
Importantly, according to the theory, we need to experience the A, B and C in our daily lives, interactions and activities to have optimal well-being, development and functioning.
In a number of studies (referenced below) over the last 10 years or so, my colleagues and I have found evidence to support the idea that when children and adults feel that their A, B and C is satisfied when thinking about being active, they experience high quality, autonomous motivation and that this is linked with greater physical activity. Common to all of these studies is the finding that motivation based on enjoyment and/or personal value is linked to physical activity, whereas motivation based on guilt or external pressure (such as rewards, or demands from others) is not. Accordingly, we have designed a number of physical activity interventions for children and adolescents with the A, B and C of motivation in mind.
When viewing The Daily Mile through this motivational lens, it is possible to see how the intervention expresses the A, B and C:
Of course, my retro-fitting of SDT principles to The Daily Mile is just one lens through which to study its broad appeal and apparent motivating effect on pupils. However, it is entirely possible for interventions which grow from the ground up to align in many ways with what is known from behavioural or psychological sciences even if they did not set out to do this from the start. Aligning the core principles of The Daily Mile with a framework such as SDT’s A, B, C may also allow the intervention to stay faithful to its design as it is adopted and potentially adapted in schools around the world.
I would argue that unknowingly, when implemented in line with its core principles, The Daily Mile could be tapping in to a well-known, evidence based and positive source of motivation for physical activity. At its core The Daily Mile is simple. Perhaps it is as simple as A, B, C.
Dr Simon Sebire is Senior Lecturer in Physical Activity & Public Health in the School for Policy Studies at the University of Bristol. He is also Interim Chief Executive of The Health Improvement Commission for Guernsey and Alderney.
References
Dr Laura Johnson, Senior Lecturer in the Centre for Exercise, Nutrition and Health Sciences, discusses her new paper in which she assesses the impact of dietary patterns on obesity and how modelling may help influence change in both personal habits and public policy.
No single food or nutrient is to blame for obesity. There so many routes from diet to overeating and weight gain, and in real life foods and nutrients aren’t eaten on their own. So, it’s misleading to look at foods that way in research, it’s the overall balance of diet that matters.
I realised this a while ago when I used detailed records of food intake from children age 5 and 7 in the ALSPAC cohort to generate an overall diet score that predicted obesity later on. I thought that eating more fat, less fibre, and having a more energy dense diet (more calories in each bite) would all feature in a diet that fuels obesity (or an ‘obesogenic’ diet). I used reduced rank regression or RRR (a pimped up version of factor analysis, see excellent explanation by Andy Field here) to find the best combination of foods to capture differences in the fat, fibre and energy density of the children’s diets. RRR generates a score based on what you eat. It’s calculated by adding up the intake (grams/day) of 42 groups of foods that are weighted for importance and a higher score means your diet is more obesogenic. I showed that children with the highest pattern score at age 7 were 4 times more likely to have too much fat by the time they were 9 years old (other researchers have since seen similar associations in adolescence and adulthood).
A pretty strong result, right? But, what use is a score made up of 42 foods? Isn’t it too complicated to ever be the basis for changing behaviour? I don’t think so, not if we use computers to deal with the complex calculations. All we need to know is what foods have been eaten (by individuals or populations) and then the obesogenic score can be computed automatically. We would then have a single score indicating whether the overall balance of your diet (or the Nation’s diet if thinking in policy terms) is more or less obesogenic. A total diet score would be better than current measures which only focus on fruits and vegetables or sugar-sweetened drinks, which let’s be honest, no one believes are going to solve the obesity epidemic on their own!
In our latest paper we asked “Do the same foods make up an obesogenic diet regardless of whether you are young or old, boy or girl, rich or poor?” (Because the ALSPAC score might only matter to children living in Bristol in the late ‘90s) “Who in the UK has a more obesogenic diet?” (Because those people need the most help to change) and “Are diets getting more obesogenic over time?” (Because that might suggest national obesity policy isn’t working).
To find some answers we used diet diaries from nearly 10,000 adults and children taking part in the UK National Diet and Nutrition Survey between 2008 and 2014. We repeated the RRR in different groups and found it was remarkably stable – the same foods came out as most important to an obesogenic diet over and over again. So, we can feel confident that the obesogenic pattern score and that way foods are weighted by importance reflects the way everyone eats in the UK today. The most and least obesogenic foods we found were (sized and in order of importance):
In terms of whose diets are most imbalanced we found massive social gradients with those in manual jobs and households earning less than £15,000/year having the most obesogenic diets, which mirrors social inequalities in obesity prevalence. Among children, diets became more obesogenic between 2011 and 2014. Among adults a more obesogenic diet went hand in hand with more time spent watching shows on TV/Laptops/Tablets, less physical activity, and eating takeaways more frequently.
All these trends are a starting point for targeting and testing interventions designed to make small changes across a range of foods to shift the balance of diet. By using our score, it could be possible to gauge how multiple changes to policy or what we eat adds up to a less obesogenic diet and with luck prevent obesity in future.
This week a paper from the EPIC-CVD which I co-authored was published in the European Heart Journal. Unfortunately the article was subsequently promoted in the press with the headline ‘Fat but fit’ still risk heart disease, encouraging a belief that physical activity offers no heart health benefit to those that are overweight.
This headline is misleading because most people understand ‘fit’ to mean physically activity, however the paper didn’t measure physical fitness. Instead it measured metabolic health (ie, high blood pressure, cholesterol and blood glucose) which some term ‘medical fitness’, and is often shortened to ‘fitness’. Hence the confusion.
What the paper really shows is that being overweight and having poor metabolic health both contribute to increasing risk of coronary heart disease (CHD), or a heart attack, to put it more simply. If you group people based on their weight status and metabolic health then the risk of having a heart attack increases in the following order:
To provide some context to these numbers, we know that having a heart attack is more common in older people – that risk increases with age by about 10% per year. Being overweight and healthy notionally makes you 2 ½ years older (in terms of heart disease risk) than a normal weight and healthy person. Whilst being obese and unhealthy notionally makes you 15 ½ years older!
My take home message from these figures is that having poor metabolic health is much worse than being overweight or obese on its own; however people carrying excess weight still don’t get off scot-free. So, if you can improve your metabolic health (whether you are normal weight or overweight or obese) you can substantially reduce your risk of CHD. Equally if you can reduce your weight (whether you have good or bad metabolic health) you can reduce the likelihood of a heart attack even further.
What about being fit, ‘physically active’ fit?
If you are overweight and are physically active then this will more than likely be good for your health – we know that physical activity has beneficial effects on metabolic health. The long-standing fat-fit hypothesis states that the health benefits of being physically active can cancel out the increased risk of being overweight, so it’s possible to live just as long if you are fat as long as you are fit. Does our work say anything about that idea? Not really, not without a lot of inference and assumptions. You’d need a study of physical fitness and weight and metabolic health to get to the bottom of that one (a study like this).
What is apparent from this analysis is that grouping people based on continuous measures of health is spurious. If you look at the ‘apparently healthy’ overweight or obese group you’ll see that their blood pressure, cholesterol, blood glucose, etc are actually still higher than the supposedly equally healthy normal weight group. To me this suggests that metabolically healthy obesity doesn’t really exist, not long-term. The people in the healthy obese group just didn’t quite meet the cut-offs for being defined as ‘unhealthy’ yet, suggesting it’s only a matter of time before they cross over to the unhealthy group.
So what’s the point of putting people in boxes, we are all individuals after all, with our own unique profile of risk factors. I’d say let’s try and keep continuous risk factors continuous and aim for lowering them across the whole range using whatever methods have been shown to work in the past. Physical activity and diet can both help in different ways, to either improve metabolic health or promote weight loss, so aiming for a healthier lifestyle is as important as it ever was.
This blog was written by Dr Laura Johnson, a Lecturer in Public Health Nutrition in the Centre for Exercise, Nutrition and Health Science, School for Policy Studies.