As Fat Bastard from the Austin Powers series once grumbled, “Carbs are the enemy.” It’s a mantra many people trying to drop a few pounds have adopted, and with good reason: For years now, the conventional thinking, as espoused by a large proportion of the many researchers and clinicians studying the topic, is that obesity is caused by caloric excess, mainly in the form of carbs. This is sometimes referred to as an “energy balance” disorder, with the treatment, of course, being to consume fewer calories while expending more. “It’s viewed as a psychological issue or even a question of character,” Dr. David Ludwig, a Harvard Medical School Professor and obesity researcher, told The New York Times in July.
But according to research published in the American Journal of Clinical Nutrition, it’s becoming increasingly apparent that carbs — like drugs or other habit-forming substances — can actually be addictive, with fast-digesting carbohydrates (such as bread and sugar) stimulating regions of the brain involved in cravings and addiction.
There’s been plenty of research in the past to show that sugar-heavy foods can trigger dopamine release in the pleasure centers of the brain. The surprising aspect of Ludwig’s research, however, is that even when people aren’t necessarily aware that they’re eating carbs, the intake of large amounts of fast-digesting carbs still activates the pleasure centers of the brain in a way that’s not dissimilar to drugs.
In other words, it’s not the deliciousness of a dessert that lights up our brain—it’s the carbs themselves.
But what is it about carbs that could possibly be so addictive?
According to Laura Schmidt, a professor in the School of Medicine at the University of California at San Francisco, “The argument is, if you have high spikes in blood glucose [caused by the carbs], they’re going to be followed by low dips, which will cause you to crave more.” But it goes beyond just your blood: Eighty-five percent of all the glucose you ingest goes to your brain, and when it thinks it’s experiencing a glycogen deficit (in reality, just a crash following the blood sugar spike), your brain will urgently crave more.
Another reason has to do with the effect of insulin (the hormone produced by your pancreas to turn the sugar from carbs into energy) on the metabolism of carbs. “Elevate insulin levels even a little, and the body switches over from burning fat for fuel to burning carbohydrates, by necessity,” Dr. Robert Lustig, a pediatric endocrinologist at the University of California at San Francisco, told The New York Times earlier in the summer. And the more insulin you release, the more you crave carbs.
Still, the notion that certain foods — specifically fast-acting carbs — may be literally “addictive” isn’t without controversy. “[The study] doesn’t tell you if this is the reason they got obese,” Lustig told NPR. “Or if this is what happens once you’re already obese.”
Basically, it’s not clear whether the cause-and-effect relationship of eating carbs and triggering certain responses in the brain is really an addiction, like drugs or alcohol, or a compulsion, like sex. “There’s a difference between compulsion and addiction,” psychologist and neuroscientist Jim Pfaus explained to us in 2016. “Addiction can’t be stopped without major consequence, including new brain activity. Compulsive behavior can be stopped; it’s just difficult to do so.”
Nonetheless, Schmidt has developed a strategy for patients who claim they’re addicted to carbs. “The standard strategy is similar to any other form of addiction: Change your environment, change your social network and carefully observe the pattern of your cravings by maintaining a diary.”
“Once you know when your trigger times are, you prepare for them proactively,” she says. “You come up with substitutes.”
So while we may not be ready to start attending Carbohydrates Anonymous just yet, it’s reassuring to know that it’s more than just poor willpower that sees us destroying a family-sized bag of chips in a single sitting.