Britain’s obesity guru: ‘Not all fat is bad – it depends on where it is’

Professor Stanley Ulijaszek has spent a lifetime trying to understand why populations become overweight. 

“Nobody chooses to put on excess body weight,” he says, sitting in an office at St Cross College, Oxford, where he is emeritus professor of human ecology. “So to try to understand why obesity should emerge as an issue, in the context of all the choices we make, is an interesting thing to think about.” 

At 69, Ulijaszek has published a new book, Understanding Obesity, which gather’s a career’s worth of learning into a readable, practical volume, looking at the many different factors – the “imperfect storm”, in his words, contributing to the international obesity crisis. 

In the time he has been working, rates of obesity and overweightness have soared around the world. In the UK, more than a quarter of adults are now obese, and a further 37 per cent are overweight. In the US, the problem is even more acute, with more than 73 per cent of adults overweight or obese. 

“The book has been in the back of my mind for a long time,” he says. “One of the issues with being an academic, in a field where you think there needs to be action, is how do you turn research into something that’s actionable? It was a challenge, being forced to think about what kind of take-homes you can offer. What kind of misunderstandings are there?” The book is part of the Cambridge University Press’s ‘Understanding…’ series, where experts unpack complicated topics. 

Drawing on decades of research, Understanding Obesity looks at many different factors influencing population weights: processed foods, societal norms and stigma, lack of exercise, snacking, genetics. “I’ve spent a career trying to destroy dominant narratives,” he says. “If we can get rid of some of those other factors, we can start to see what’s really going on.” Rather than present faddish solutions, Ulijaszek offers a level-headed look at where the science differs from popular wisdom. 

“Fat, in many contexts, is good,” he says. “We all carry it for good evolutionary reasons. It regulates so many different things. But at what point does it become excessive, and for whom? 

“Not all fat is bad,” he adds. “Many women have large hips, bums and thighs. It’s difficult to shift that, it’s often a genetic predisposition. Recent evidence suggests that it is healthy protective fat. But the kind of fat I’m likely to deposit, around the gut, is deeply unhealthy. Where you deposit fat matters hugely. It does different jobs in different places.” 

Ulijaszek came to study obesity through anthropology. He completed his doctorate in Papua New Guinea in the 1970s. When he returned 25 years later, he was startled by the change in the population’s health. “Type 2 diabetes was an issue, hypertension was an issue, overweight and obesity was an issue, from people who had been extraordinarily lean. Trying to understand how a group of people in a very remote place could suddenly develop what they call diseases of civilisation. It didn’t fit.” 

What he observed in Papua New Guinea was happening around the world, including in India and Kenya. “The first thing that people do when they have a bit of money and want to improve their food is put salt on it, because it’s cheap and improves the taste,” he says. “Sugar follows. We have an evolutionary predisposition to like sweet foods.” 

In Britain, he says, our predisposition to sugar is partly a consequence of our history. “This country historically produces so much sugar, and there’s a strong sugar lobby, and that’s part of what we’ve seen in terms of obesogenic environments.” 

In America, since the 1970s, one potent source of calories has been high-fructose corn syrup (HFCS), the sweetener which arose from a corn surplus and replaced sugar in many soft drinks. In 2012, Ulijaszek was the co-author of a paper which showed that large amounts of HFCS could be contributing to the rise in Type 2 diabetes. 

“It doesn’t satisfy appetite, it results in fat being deposited in the wrong place, it gives you an insulin spike,” he says. “In terms of long-term, nobody just eats HFCS. It’s an ingredient as part of a diet. The food industry will say time and time again that nobody just eats a Mars Bar. To prove the negative effects of some aspects of diet you have to eat diets that are mostly composed of those.” 

If Britain and America have been mostly cautionary tales in recent decades, other countries offer hope. Working in Japan, he saw a society just as industrialised and consumer-driven as the UK, but with far fewer overweight and obese people. “Eating a snack in the street in Japan, people tut at you. There’s a strong social sanction against snacking. You should not be eating in the street. If you’re hungry, wait and eat a meal. There’s also a culture of hara hachi bu, eating to 80 per cent, rather than until you’re completely full. The social forces for eating in the right way are very powerful. Eating at mealtimes is a social convention which we kind of have here in the UK too, but it has been disrupted by market forces – snacks and so on.” 

Scandinavia, too, has a more healthy approach. He spends a lot of time working in Denmark, which has an obesity rate of just 18 per cent, albeit rising, and where he says Britain is held up as a cautionary tale. The Danish focus, as in other Scandinavian countries, is on reducing inequality and inculcating healthy food habits from a young age. “The Scandinavians are keen on child-centred policy,” he says. “If you sort the first five years then a lot of the issues you would have to retrofit solutions to are diminished. I always come back from Copenhagen feeling positive about the future.” 

Take breastfeeding. “Breastfed children are less likely to put on excess weight,” he says. “There’s good evidence for that now. We all have a genome ever since humans evolved and obesity was never a common issue. But it is now. One of the reasons why is eating too much, but we’re also switching on the genetics for putting on excess weight. If you’re formula fed you’re more likely to have the genetics for expressing excess weight than if you’re breastfed.” Paradoxically he says that a low birth weight is associated with risks of obesity later in life. 

The current food industry villains are ultra-processed foods. “We’re reasonably clear how those things operate, but you can’t definitively say ‘if you buy this, it will kill you,’ he says. “With cigarettes you could say that.” Does he think food will carry warnings like tobacco products? 

“I hope so,” he says. “The one thing governments can do is regulate. If you get in a car you put on a seatbelt and there are speed limits. We accept that regulation because it keeps us safe. Why not do that with food, when it’s clear that this food is not safe? The difference is that it’s a slow-motion car crash, unfolding in front of us. That’s the tragedy in the work that I do: you can see the car crash coming.” He says the sugar tax was a step in the right direction, but more could be done. 

Above all, Ulijaszek wants governments to take a compassionate and holistic approach to obesity that doesn’t blame individuals. “Part of the message of the book is that there are so many other ways you might be able to deal with obesity rather than saying ‘war against obesity’,” he says. “People think, ‘if it’s a war against obesity it’s a war against me, because I’m obese.’ If half the country is obese, that’s a civil war.” 

Ulijaszek, who is married with three grown-up children, keeps healthy with cold-water swimming, which he does year-round. He is not immune to being nagged about his own weight. “My BMI takes me into the overweight category, which prompts the clinician on my app to say ‘do you want to see someone about your weight?’ That really annoys me. It probably annoys everyone who gets it. Everyone knows where they sit in relation to their body size.” 

“Ultimately this book is about treating yourself with dignity,” he concludes. “From time to time it’s useful to stand in front of the mirror naked and look at what you see, and work out what you’re comfortable with, and how you live life well. That’s the ultimate political question: how should life be lived?” 

Understanding Obesity by Stanley Ulijaszek, Cambridge University Press £14.99