Everyone Calm Down for a Minute About ‘Sugar Addiction,’ Neuroscientists Plead

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Photo: Spencer Jones/FoodPix

You have, one assumes, seen the headlines. Like this one: “Sugar addiction like drug abuse, study reveals.” Or this one: “The 15 signs you could be a sugar addict.” Sugar, a wave of recent research has suggested, is as habit-forming as hard drugs are, a catchy idea that has helped shape the way people today think about the food they eat; even someone as physically formidable as Dwayne “the Rock” Johnson considers himself no match for the allure of a craft services table of doughnuts, due, at least in part, to a sugar addiction.

The notion makes intuitive sense. And yet, recently, a team of neuroscientists from the University of Cambridge investigated the evidence: Is “addiction” really the best way to think about the behavioral and biological response to sugar? In short: Well, no, probably not, they conclude in their review of the literature, published online this month in the European Journal of Nutrition, in which they call the scientific evidence on sugar addiction “far from convincing.” Let’s review their review, shall we?

Very few of these studies have been done on actual humans. Most of the research they found on sugar addiction was done using mice or rats, and it’s not clear that these findings will translate perfectly to people.

Also, the rodents in these studies were selected for these studies specifically because they really dig sugar. In choosing rodents for these studies, scientists tend to select for “sucrose preference” — that is, they pick the animals that have already been exposed to sugar and have already shown that they love it.

The neurochemical responses don’t really resemble addiction. When rodents are given sugar, levels of dopamine — that chemical associated with reward and motivation — temporarily increase, but then resettle to normal levels after repeated exposure to sugar. When they’re given cocaine, on the other hand, that dopamine surge “does not return to baseline but further increases after lever pressing and cocaine delivery,” the authors write. One doesn’t behave like the other, and so equating the two in a nifty metaphor doesn’t quite work.

It’s not that sugar addiction is definitely not real; the message here is more like “Just hang on a sec.” It’s something especially important for policymakers to keep in mind before adopting a too-narrow view of how to address the health risks associated with poor nutrition and obesity; it’s also something for those of us, the Rock included, to keep in mind when facing the temptation of free pastries at work.