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| Robert Lustig |
Robert Lustig and I are watching a video of Eric Clapton. The musician is talking about how his struggles with addiction date back to a childhood obsession with sugary foods.When the video ends, Lustig looks at me. “Sugar is a gateway drug,” he says.
As we sit overlooking a huge construction site on a floor filled with cubicles at the University of California, San Francisco, Lustig tells me that, like cocaine, sugar can become something we crave. It feeds our brain’s reward system, and he thinks that as we build up tolerance we can’t get the same fix and may be tempted to move on to more dangerous substances.
Lustig pulls no punches when it comes to criticising sugar. Over the past 15 years, this pursuit has driven–and ultimately overtaken– his career as a paediatric endocrinologist. As we talk he is direct, emphatic, his eye contact unwavering and his points punctuated with expletives. This blunt manner has helped him turn sugar into one of the arch villains of public health.
The construction site below us will eventually become a basketball stadium. But by then, Lustig will be long gone. This month, he is retiring from clinical medicine to pursue a cause that has come to define him and which now encompasses all the ills of our pleasure seeking society.
It began in 2002, when he went to a talk about fructose. This is the sugar found in fruit that combines with glucose to form table sugar. Our bodies process fructose and glucose in different ways. Too much glucose and we accumulate body fat. But excess fructose turns into something much more insidious: liver fat. Lustig learned that far more fructose might be converted into liver fat than was previously thought.Having studied nutritional biochemistry before medical school, he kept coming back to the idea, thinking fructose might have some bearing on his work treating children with hormone disorders. It used to be that his patients came in for problems such as stunted growth, but increasingly, they were arriving with issues related to obesity. The shift surprised him. As he puts it,“My job was to take care of short kids, not fat kids.”
Lustig is proudly unencumbered by the niceties or arcane jargon that usually restrain researchers.He frequently refers to“big butt fat”and isn’t shy about the term“couch potato”. In his 2012 book 'Fat Chance', he warned that if we don’t halt the obesity epidemic, “We’ll all be so fat, we’ll have to ride around on little scooters, just like at Walmart.”
By 2006, most of his patients were obese. That’s when he got an invite from the US National Institute of Environmental Health Sciences to speak about childhood obesity at a conference. It got him thinking about fructose. The obese kids he was treating often had fatty liver disease, a condition seen in alcoholics that has been linked to metabolic syndrome. This is a cluster of symptoms, including insulin resistance, associated with an increased risk of heart disease and diabetes.
When he dug through the research, the case against fructose seemed to come together. He became convinced it was a toxin akin to alcohol. What’s more, obesity and type 2 diabetes appeared to be rising in concert with sugar consumption. Sugar isn’t just harmful for the extra calories it gives us, he thought, it plays an outsized role in driving metabolic syndrome. “It was very anxiety-provoking,” Lustig says. If it were true, it would mean taking on the food industry. “It was half ‘Eureka!’ and half, ‘Oh my fucking shit’.”
He announced his idea at the talk, in early 2007. The audience was stunned. A public lecture on the same subject – in which he described sugar as “poison” and “evil” – was posted on YouTube and quickly got tens of thousands of views. That number has now risen to more than 7 million.
Lustig deserves a great deal of credit for highlighting sugar’s potential dangers. But even those who back his views are at times wary of his methods. His first book, critics noted, often presented hypotheses as facts, skimping on the usual caveats and hedges. US journalist Gary Taubes, whose latest bookis 'The Case Against Sugar', admires Lustig and buys his argument. He gets frustrated, though. Even though Lustig could not have known that the video would go viral, “he makes all kinds of factual errors”, Taubes says.
But Lustig gets people’s attention, and he knows it. “In order to change people’s minds, you have to hit them cognitively and viscerally at the same time,” he says. When you’re challenging widely held and seemingly simple ideas like “a calorie is a calorie”, people get defensive. “You have to disarm them.”
Another criticism is that he overhypes the evidence. Luc Tappy, who studies obesity at the University of Lausanne in Switzerland, worries about the temptation to take shortcuts. He thinks Lustig is too quick to draw a direct line between sugar intake and type 2 diabetes, for instance. When I question this, Lustig jumps up to print out his latest research. “This is the smoking gun,” he says, dropping the paper on the table. “We’ve got causation.”
It is a study of 41 obese teens, showing that if they ate the same amount as usual but replaced fructose with starch for 10 days, they lost liver fat. Combined with the link between liver fat, insulin resistance and diabetes, it is certainly suggestive. But a study of 41 teens will hardly bring the sugar industry to heel. “He’s overly optimistic about what his studies can and cannot demonstrate,”says Taubes.
Some critics go further, even painting Lustig as a charlatan. He got hate mail after an essay outlining his ideas appeared in 'Nature' in 2012. But Lustig remains largely unfazed. Now 60, he says the pressure to succeed that he once felt has eased off. “I have a sense of achievement,”he says.
The world is taking a closer look at sugar. Mexico now taxes sugary drinks and the UK is bringing in a sugar tax next year. The US plans to change food labelling to mention added sugar. People can criticise, but so far it seems he’s on the side of right.“They’re not going to shake my faith inmyself,”he says.
Brimming with confidence, Lustig is now taking on modern society in general. His new book, 'The Hacking of the American Mind: The science behind the corporate takeover of our bodies and our minds', is every bit the polemic its title suggests. He points to everything from smartphone obsession to the US opioid epidemic as evidence that marketeers are exploiting the brain’s reward system to make us value instant gratification over longer-term contentment. The cleverly coaxed hedonism of the West is undermining our health in many ways, he believes. Sugar is just one part of a much larger picture.
He has just finished trying to frame this argument when I commit the ultimate faux pas: I ask about his weight. Over the past decade, he has lost about 20 kilograms. He used to mention his weight as evidence that he too is prey to the dangers of the modern food environment; he almost wore it proudly.
Yet as he recalls the vitriol of those who commented online that being fat himself, he had no business telling people how to eat, he suddenly seems bitter, even vulnerable. Perhaps those feelings are part of what drives him. As he knows all too well, the quality of life for obese children can be similar to that of children battling cancer. For him, those are the stakes. “We have already lost one generation of kids,” he says. “We can’t lose another.”
By Tiffany O’Callaghan in "New Scientist", USA, n. 3142, September, 9, 2017, excerpts pp. 42-43. Digitized, adapted and illustrated to be posted by Leopoldo Costa.