Speaker Spotlight
Professor Giles Yeo
Giles Yeo is the Professor of Molecular Neuroendocrinology and programme leader at the MRC Metabolic Diseases Unit at the University of Cambridge whose research currently focuses on the influence of genes on feeding behaviour and body weight. An author and broadcaster, his first book, ‘Gene Eating’ was published in December 2018, and his second book, ‘Why Calories Don’t Count’ came out in June 2021. Giles was appointed an MBE in the Queen’s 2020 birthday honours for services to ‘Research, Communication and Engagement’. He won the Society for Endocrinology Medal in 2022. In addition, he is a fellow of Wolfson College and Honorary President of the British Dietetic Association.
In his talk, ‘In a post-Ozempic world, have we cured obesity?’ at the Cambridge Union, Giles will explain the mechanisms of action of these drugs, discuss their importance as a therapeutic for obesity, type 2 diabetes, and heart disease, and crucially, whether or not they are safe in the long term.
"I think the biggest misconception is that people think that obesity, body weight in general, is a choice."
Tell us about your research
I study the genetics of body weight, which is by definition the genetics of how our brain controls food intake. I'm interested in is how the brain responds to circulating hormones from fat (which are your long term energy stores), and from the gut (what we're currently eating and what we have just eaten). Weight loss drugs are modified gut hormones that signal to the brain, so I also study how do these drugs signal to the brain.
Your work focuses on the genetics of obesity and feeding behaviour. What recent discoveries in this field have surprised you the most?
I think there's been two big recent technological developments that have occurred over the past five years, that have provided us with the opportunity to study and understand more about the biology underlying the system.
First, from a genetics perspective, is high throughput sequencing at scale. In the not so distant past, we would have to sequence each gene individually in small groups of patients. But because now we have these high throughput sequencing technologies that are relatively cheap, we can now sequence every single gene in hundreds of thousands, of people all at once.
The second thing is our ability to use single cell and spatial approaches to be able to map the brain. We started with mice, but now working with postmortem samples, we're able to map the human brain as well down to single cell level.
You mix the two together, suddenly we're discovering more fine-grained genetic information that influences feeding behaviour, and now we're now able to take some of these genetic findings into the human brain. We're arriving at an explosion of information making the next few years very exciting!
How do you see the role of genetic research evolving in tackling obesity at a population level?
I think there are three different ways of thinking about it. The first one is societal wide, as a way of tackling weight-stigma. What I mean by this is the more evidence that we gather, and therefore demonstrate that there is a genetic basis to body weight, that it's not just based on ‘willpower’, the more powerful an educational tool.
I think the second thing is if we identify new genes linked to body-weight, we can identify potential novel candidates to therapeutically target to try and treat obesity.
And third, we can, using genetics, identify people who will not respond to a drug or treatment, or will over or hyper respond to a drug or treatment, therefore display side-effects. For those two groups of people, we can treat them with something else. What we clearly want is to increase the efficacy of any intervention to 100%, while reducing side-effects to as close to 0% as possible.
What are the biggest misconceptions the public has about obesity and its causes?
I think the biggest misconception is that people think that obesity, body weight in general, is a choice. Body weight is a direct result of eating too much, but the genetics influences why people eat.
The thing is buying or eating food is a very public thing. When we go to a supermarket, we can see what everyone's in everyone's baskets. If you go to a restaurant, you can see what everyone is eating, how much everyone is eating and what they're eating. Our primitive brains then often judge the people buying or eating the food, particularly if they are larger. In our heads, it looks like a straightforward choice.
However, any given meal that we eat is not going to perceptibly change our body weight. Our body weight is the function of many thousands of feeding events that have happened over the past few years. But imagine if because of your genetic hand of cards, that you are a little bit less likely to say no. 5% less. So one out of every 20 times you end up eating more food or an extra slice of pizza.
5% over thousands of feeding events is hundreds of thousands of calories. So over the period of time that feeding does begin to influence your body-weight, it is not a choice. In casino terms, the house will always win. That's why I think that obesity is not a choice.
Giles presenting at the Cambridge Festival 2024.
Giles presenting at the Cambridge Festival 2024.
You’ve presented documentaries and written books like Gene Eating and Why Calories Don’t Count. What inspired you to move into science communication?
In the early 2000s, I went to dinner at one of the Colleges as a postdoc. I remember sitting down opposite a professor, and while explaining what I do, he cut me off, pointed at me, and said “do you know what your problem is? You give fat people an excuse”.
I was sat in the cab on the way home and I was thinking to myself, this guy's an educated individual. He's a professor here at Cambridge but this is his view on body weight. And it was at that point, I realised that if I wanted to stay within this field, I'm I needed to do more than just my science. I also needed to communicate the science to other people. That was the moment I decided I to really take science communication about body-weight and weight stigma seriously.
You’ve held many roles—researcher, tutor, author, broadcaster. Which has been the most rewarding, and why?
Clearly, I'm a scientist and I love making discoveries, but I think the most rewarding is teaching.
If you could change one thing about how society approaches diet and health, what would it be?
Embrace the noise. I think the problem is at the moment, people think that it's my way or the highway, one-size-fits-all. You have to do this, you don't eat that, and this is the way to do it. I think the answer is almost always, ‘it depends’.
Listen to Giles' new radio show now ⬇️
"The more evidence that we gather, and therefore demonstrate that there is a genetic basis to body weight, that it's not just based on ‘willpower’, the more powerful an educational tool."
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