Your brain sees sugar as a reward. But does that mean it’s addictive?

Psychologist Ashley Gearhardt remembers one type 2 diabetes patient who acknowledged that eating pillowy Krispy Kreme doughnuts is devastatingly bad for her. Knowing that the donuts could worsen her disease didn’t stop her from driving out of her way to secure a box of the sweets.

“Clearly, compulsivity is happening,” said Gearhardt, a University of Michigan professor and one of the creators of the Yale Food Addiction Scale, a self-reporting tool that helps people find out whether they are at risk for food addiction. In her view, that inability to control an urge helps make the case that sugar is addictive.

Add sugar’s mood-altering effects to the argument. One Super Bowl commercial sticks in Gearhardt’s mind like no other. The 2015 ad features actor Danny Trejo, known for his rasp and various tough guy roles, wielding an ax and complaining to iconic TV parents Carol and Mike Brady in their 1970s split-level home. After he eats a Snickers bar, he’s transformed into a smiling and pleasant Marcia, the oldest kid in the blended Brady family. The ad is a cultural expression of something Gearhardt believes is real: that humans can become dependent on the sweet stuff.

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“We know that people aren’t just eating these foods for calories but because they want to feel pleasure. You can see that in the marketing all the time. You’re angry? Eat a Snickers. So [sugar consumption] is causing shifts in mood.”

Since that time, the idea of sugar addiction has gained steam, partly due to a much-publicized 2017 article that suggested rats prefer sugar to cocaine. But one study doesn’t make a consensus, and scientists have divergent opinions about whether people (or rodents) can become dependent on sugar.

What’s not in doubt is that sugar affects our development and our brains. Giles Yeo, professor of molecular neuroendocrinology at the Medical Research Council Metabolic Diseases Unit at the University of Cambridge in England, points out that mammals’ milk contains the fat and lactose sugar babies need to grow as quickly as possible and avoid becoming prey. And we feel good when we consume sugar because our brains see it as a reward.

But that does not make it addictive, according to Margaret Westwater, a postdoctoral fellow at the University of Oxford and Yale School of Medicine. She conducted a 2016 review of scientific research about sugar and addiction. She and her co-authors found no support for the idea that consuming sugar leads to behavior and distress in the same way as drugs of abuse.

In a chapter in a forthcoming edition of Food and Addiction: A Comprehensive Handbook, Westwater further debunks the notion that rodents will choose sugar over cocaine due to the sweet substance being more addictive than the narcotic. She explains that rodents get an immediate dopamine response from the taste of sugar. Cocaine, on the other hand, needs more time to metabolize and increase dopamine release. It delivers a delayed but much more forceful punch, with dopamine increasing 120%. When given cocaine or amphetamines, rodent brains release dopamine to 300% to 900% above the baseline, she said. Sugar’s pleasure-inducing spikes are nothing compared to the hormonal surges that follow use of those drugs.

That makes sugar much like anything else that “lights up the parts of the brain that make us feel nice” said Yeo, and that “includes drugs of abuse, which [are] addictive, alcohol, smoking, bungee jumping, sex, all of it – and sugar. So therefore, there are addictive elements to it.”

He continued: “Now, I’m not trying to bamboozle anybody with verbal gymnastics. When you speak to actual psychiatrists who work with addiction, sugar – while superficially covering aspects of addictive pathways – is not, in and of itself, actually addictive. It’s not like nicotine; it’s not a drug.”

Gearhardt differs and thinks the very definition of addiction needs to be revised.

“I struggle sometimes with what people are using for their benchmark for, how do you know when something’s addictive, because it’s actually been a constant topic of debate. We actually thought cocaine wasn’t addictive back in the 70s because its withdrawal syndrome didn’t look like [those of other] addictive drugs. What you use to make that designation is really important and shouldn’t just be brushed over.”

She and her team are proposing that “highly rewarding” and ultra-processed foods – many laden with sky-high amounts of sugar, salt and fat – be classified as addictive substances in various diagnostic frameworks. Those reference guides, such as the International Classification of Diseases and the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM), help healthcare providers identify a patient’s condition, and legitimize a condition.

Gearhardt’s team aims to submit their DSM application this summer. Once they do so, a steering committee of psychiatric experts will evaluate the evidence and seek public comment, if they decide there’s enough evidence. The committee can decide to forward a recommendation to the association’s decision-making bodies for final approval.

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Gearhardt thinks there is precedent for change. She said the controversy around tobacco and cigarettes was resolved based on the following criteria for addiction: that a substance triggers compulsive use and affects moods, and that both people and animals will work hard to get it. Gearhardt’s team is proposing a new criterion: that a substance triggers strong urges and cravings.

If that proposal is approved or if researchers reach the now-unlikely consensus that sugar is addictive sometime in the future, what happens next? With nicotine, cigarettes eventually were labeled with a warning, despite tobacco companies deliberately misleading the public on the risks of smoking cigarettes. That industry’s youth marketing was severely curtailed, which might be an option for regulating sugar, since as Yeo pointed out, youth might be uniquely vulnerable to it.

But Emily Broad Leib, a Harvard Law School clinical professor and director of the university’s Center for Health Law and Policy Innovation, believes systemwide solutions will be an uphill battle. This is true despite successful campaigns in several US cities (and several countries) to address sugary drinks – for example, by taxing sodas. Sugar is low-cost and commonly added to everything from salad dressing to bread; even people who monitor sugar intake can hardly keep up with where the sweet stuff shows up. Leib says food and beverage companies capitalize on the lack of guardrails and accountability for how much they sweeten products.

“They’re unfettered in the decisions they make about how much sugar to use,” Leib said, and probably just as likely as big tobacco to resist any efforts to change.