CamFest Speaker Spotlight: Professor Giles Yeo

Cambridge biologist Professor Giles Yeo, author of books including Why Calories Don't Count, is in conversation with Nazia Mintz Habib, Founder of the Centre for Resilience and Sustainable Development at the University of Cambridge, about the long-term impact of diet and hunger on our physical and mental development in the event Hunger: how what we eat - or can't eat - affects our mental and physical health, March 28th, 6-7pm, Cambridge Union. 

What motivated you to get into metabolic research? 
It was serendipity really. I was a geneticist and I needed a job. I did my post doc in the genetics of severe obesity in children. As I began to identify new genes, I moved away from looking at the genetics of severe obesity in children to the genetics of body weight in general and from there to looking at how the brain influences feeding behaviour. 

What are you working on at the moment?
We have found a new gene ‘bassoon’ that, when mutated, is associated with an increase of four body mass index points in the population, which makes this the gene with the largest effect size on body-weight on a population basis. On top of that, it is, unusually, liked with adult obesity and not childhood obesity.

While your research shows the importance of the role genes play in obesity, this also interacts with what we eat. What effect is the cost of living crisis having on obesity levels in the UK? 
Obesity is getting worse due to the cost of living crisis. In the UK the healthier option is rarely the cheaper option. What's more, while lentils and beans may be cheap, the problem is that you have to take into account the cost of the energy needed to cook them compared to heating up a pre-prepared meal in the microwave.

We are in a cost of living and an energy crisis so both must be taken into consideration. People buy ultra processed foods because they are cheaper in price, convenient and energetically cheaper and the cost of living crisis has exacerbated this situation.  

How can we change things for the better?
For the long term we have to make healthier options cheaper and more convenient. Then we will be able to tackle diet-related illnesses equitably. This will take time. In the short term, we need to resist the temptation to demonise ultra-processed foods. Many people have no choice over what they eat.

Rather than demonising these foods we need to work with industry to make them healthier by, for instance, adding more fibre or protein to them, introducing a Trojan health horse into people's diets. The food industry doesn't want to poison people, but we need to find a way to change people's diets that does not make them less competitive. 

How can we reduce obesity through education?
First, we need to nip it in the bud by focusing on primary school-aged children. And then we need to consider what we do when those children get pocket money and look at the environment near their school.

When it comes to their parents, there are different levers to pull. Their parents may already be obese and that needs to be treated. And for older people we need to encourage more exercise. Each stage of life requires different tools and we need to tackle them all in parallel. 

Why do you think more investment is not made in prevention? 
It is because treatment is taken care of by the drug companies. Prevention requires policy change in government. There is concern that government may use drugs as a reason not to tackle obesity through policy changes. 

What kind of feedback have you received from your last book which questions the value of calorie counting - from consumers and from industry? 
A minority of people think I am being anti-physics when I say that calories don't count. There has been a huge resistance to accepting what calories are from 'gymbros' who are fairly evangelical calorie counters.

On the industry front, there is a good deal of ignorance about how much we do not know about calorie labelling.  My engagement with industry has been quite positive, but each individual company has little power as they have to follow certain guidelines.

We need to be speaking to the policymakers about the quality of the food we are eating rather than the amount of food people are eating. Calories don't tell us that.  

Through your books and your commitment to public engagement events like the Cambridge Festival you seem keen to engage with the public. Why does this matter to you? 
Prevention requires policy change and it requires people to be informed so they can lobby government and vote for parties that will bring change.

An informed public will lobby and educate politicians. That's a big reason why we as scientists continue to communicate the science of what we do outward.