Susan Jebb OBE is the Professor of Diet and Population Health at Oxford’s Nuffield Department of Primary Care Health Sciences, Chair of the Food Standards Agency, and a Senior Research Fellow at Jesus College. Her research focuses on how to achieve healthy and sustainable diets.
As she explains in this interview, much of her research seeks to identify what interventions might be effective in helping people lose weight and reduce the risks of obesity-related diseases.
How did you come to be at Jesus College?
I trained as a nutrition scientist at the University of Surrey, qualified as a State Registered Dietitian and in my PhD I studied in body composition and energy metabolism at the University of Cambridge. My post-doctoral research in the early 1990s looked at why people with cancer and HIV often lost weight, but when new treatments for HIV and better nutritional support became commonplace, I turned my attention to why more and more people were gaining too much weight. I spent many years at the MRC Human Nutrition Research Unit in Cambridge, where I was a Programme Leader, and moved to Oxford in 2013 to take up the position of Professor of Diet and Population Health.
Tell us about your recent research
I focus on finding solutions to either prevent or treat obesity. Currently, two-thirds of the adult population is overweight – so in our publicly funded healthcare system, we need interventions that are effective and cheap enough to be offered at scale. But we also need to find ways to prevent so many people becoming overweight. That is likely to require changes in the food system – everything from subsidies for food production through food processing, advertising of food and drinks and our cultural attitudes to food. Recently we’ve also been working on how to make our diet more sustainable too, with an emphasis on reducing the amount of meat we consume but also encouraging more sustainable forms of production. I love working on these issues because it’s such a fascinating mix of natural and social sciences, with some economics and politics on top!
Do we know how to treat obesity?
Yes! Many people who are overweight try to lose weight on their own, perhaps following a book, or video or just picking up tips from friends. Research shows that on average these efforts lead to rather little weight loss. But people who enrol in a formal, structured programme lose much more weight.
Our clinical trials have shown that if a GP offers people the opportunity to attend a community weight-loss group such as WeightWatchers or Slimming World, on average they lose twice as much weight compared to receiving advice from their practice nurse. The groups provide motivation and support to lose weight and people find that regular contact really helps them to succeed. On average, one year later, people are about 5kg (11 pounds) lighter.
This research helped NICE (the National Institute for Health and Care Excellence which provides evidential guidelines for medical treatments) to decide that these programmes were cost-effective and to recommend their use by the NHS. As part of the Long-Term Plan for the NHS community groups offering advice on weight loss, a healthy diet and physical activity are now offered to people at high risk of type 2 diabetes. We have shown that this leads to successful weight loss and a reduction in blood glucose levels, which is likely to indicate a reduced chance of developing diabetes.
Recently we have shown that people can lose more weight by following a total diet replacement programme. Here people replace all their usual food with specially formulated products such as soups, shakes and bars for 8 weeks before gradually returning to food and receive behavioural support from a specially trained nurse or counsellor who helps them to stick to the programme and then to adopt a healthy diet. On average, people following this type of programme were 10 kgs (1.5 stones) lighter after one year. Other researchers showed that this weight loss could help almost half the people with type 2 diabetes to achieve remission from diabetes. NHS England has now announced it will offer this treatment to 5,000 people in England with type 2 diabetes and if this early pilot testing is successful it will be offered as a standard treatment for people with recently diagnosed type 2 diabetes.
Now we have effective interventions to help people lose weight we need to encourage doctors to offer these treatments to people with obesity. In medical culture, it is accepted that GPs will offer patients help to stop smoking, but it is less common for them to intervene to encourage weight loss. In another trial where we trained GPs to offer weight-loss interventions at the end of a routine consultation, 40% of people decided to attend a weight-loss programme and successfully lost weight. Even among people who decided not to take up the suggestion, almost everyone thought it was appropriate and helpful for the doctor to offer help to lose weight to reduce their risk of developing weight-related conditions such as diabetes, high blood pressure and heart disease.
What other interventions have you recommended to improve public health?
We need to change the world we live in! People do not want to be overweight, but most people find they gain too much weight as they get older. Although we know we need to eat fewer calories, it’s not always easy to put our good intentions into practice, especially when we are surrounded by cheap, tasty foods, with big advertisements encouraging us to buy things we don’t really need. We do need to help people to make more conscious choices about what they eat, but we also need to find ways to make healthy eating very much easier for everyone. That means working with manufacturers and retailers to make their products healthier and shifting the marketing of food to promote healthier options.
We looked into a number of specific interventions which might be helpful. For example, we’ve shown that nutritional labelling – such as the traffic light system used in major supermarkets, or calorie labelling in restaurants and coffee shops – does help people to reduce their energy intake by around 7%. But more significantly it changes the behaviour of the food companies who try to reformulate a product rather than have it fall into a red traffic light category, or to cut the calories on some of the most calorie-laden items on their menu – few people want a dish with more than 1000 calories. We have also shown that reducing portion size works – people served a smaller amount of food are satisfied and don’t compensate for it later with additional snacks.
Much of our current research is looking at how we can influence food purchasing by changing the way food is positioned or promoted in grocery stores. Putting items on the checkouts, at eye-level on the shelves or the end of an aisle increases sales, so can we use these sites to encourage healthy, rather than less healthy food purchases?
Price is a big issue too. Earlier this year I published a paper with colleagues in Cambridge and London showing that a price rise on high sugar snacks, such as through a tax on these products would significantly reduce sales. Our modelling showed that this would lead to a reduction in the total number of calories purchased and a slight decrease in obesity rates.
Why did you choose this topic?
I find the whole issue of weight control endlessly fascinating. Since I was a student, obesity has increased from 7% to 25% of the population and another 35% of adults are overweight. For years it was thought some people had a metabolic problem or an appetite disturbance which put them at risk, but now we realise that we are almost all at risk of becoming overweight. Something in our environment has changed. We have sedentary jobs and do little physical activity so we aren’t burning off so much energy. At the same time, food is cheap, convenient and almost constantly available – so almost everybody has to find a personal strategy to manage their weight. It shouldn’t be this hard and with the right policies in place which encourage change within the food industry, we could make a big difference.
Meanwhile, treating obesity is a really effective way to improve the health of so many people. Whether it’s cutting the risk of diabetes, lowering blood pressure, preventing heart disease or some cancers, reducing the pain of osteoarthritis or the symptoms of asthma, or helping more people to conceive without the need for IVF. There is growing evidence that weight management is one of the most holistic interventions we can offer to improve health and wellbeing. In my role at the university, I have the most fantastic opportunities to work with amazing colleagues on fascinating research studies, advise on policy and contribute to the public discourse on diet and health especially through the media. I’ve had huge fun making documentaries with the BBC, such as ‘What’s the Right Diet for You?’ and ‘The Crash Diet Experiment’ and helping people to lose weight and improve their health at the same time. All of the work is interesting and exciting – why would I not want to do it?
What are some of the impacts of your research?
Behaviour change takes time and interventions around food are hard to implement because what we eat is such a personal matter and very emotive. Governments are cautious about getting involved and the food industry is often reluctant to change. But we are making progress and we’ve had enough small wins along the way to make it feel worthwhile persevering.
I’ve been involved in developing reports for the government on how to tackle obesity, including the influential Foresight report ‘Tackling Obesities: Future Choices’ in 2007. I was a science advisor to the government on obesity and food policy for eight years, I chaired the Public Health Responsibility Deal Food Network which developed voluntary agreements with industry to improve the food environment and I am now a member of the Public Health England Obesity Programme Board.
It’s rarely the case that just one study leads to change, but I think our research has been influential in furthering the narrative about treating obesity to prevent and treat disease, and showing that it is possible and affordable to do this at scale. The important thing now is to work with NHS England to help them take the scientific evidence and use it to make change happen on the ground in everyday clinical practice.
What will you be focusing on in future research projects?
I have just begun a project funded by the Wellcome Trust titled LEAP (Livestock, Environment and People) which aims to understand the health, environmental, social and economic effects of meat and dairy production and consumption.
I am working with other researchers, including Charles Godfrey (who used to be a Hugh Price Fellow at Jesus College) and Ray Pierrehumbert, another Jesus Fellow, on a cross-university project. We know that red meat and processed foods are bad for health, that livestock is a big source of greenhouse gases, and that deforestation, often for meat production leads to biodiversity loss. So, we are looking for solutions – are there some farming methods that are less environmentally damaging than others? How can you persuade people to eat less meat? Are meat substitutes helpful?
This project is just beginning, but it is very exciting, and ultimately, we hope to be able to provide the evidence and tools that global decision-makers need to promote healthy and sustainable diets for the future.