Sugar is apparently the enemy. More so than fat or calories themselves, sugar is considered the most dangerous thing you can consume and has been compared, even by scientists, to heroin. Newspaper headlines warn, “Sugar is as addictive as cocaine and heroin.” One article even pondered why people go to prison for selling drugs but not for selling Oreos.

I’m a professor of health psychology, and when I give lectures on healthy eating, I often discourage people from cutting out any particular foods or food groups. Inevitably, the first question I get is, “Even sugar?” Once, when I mentioned to a fellow scientist that I was fine with my kids eating sugar in moderation, he could barely hide his horror as he said that I must be fine with them using a little heroin now and then too.

The earliest connection of sugar and heroin that I can find in print comes from a 1978 nutrition book with the subtitle “New Lifestyle for Super Good Health.” It states that “the only difference between heroin addiction and sugar addiction is that sugar doesn’t need injection, is readily consumable because of its availability, and isn’t considered a social evil.” Are those really the only differences? Is sugar just as addictive as heroin?

Not quite.

Definitions of addiction abound, so let’s look at it from a few angles, starting with the most common: physical dependency. When people think of drug addiction, they tend to imagine biochemical components of the drug causing physical changes in the person, which in turn make the person want the drug so desperately that it becomes nearly impossible to resist.

That’s a pretty accurate description of physiological dependence. Dependence is characterized by two key symptoms: tolerance and withdrawal. Tolerance is the need for more and more of the drug in order to get the same effect. Withdrawal effects are unpleasant symptoms that occur when the drug is taken away. Withdrawal symptoms from heroin (which include anxiety, depression, agitation, cold sweats, chills, severe muscle and bone aches, nausea, vomiting, cramps, and involuntary limb spasms) are often so unpleasant that the addict will take the drug solely to relieve those symptoms rather than to achieve the pleasure that was initially achieved.

If your concern is that you will develop a physiological dependence on sugar, you needn’t worry. That kind of addiction, like one might have to heroin, is simply not going to happen.

Despite anecdotal claims, neither tolerance nor withdrawal has been shown scientifically in humans with sugar or any other nutrient or food (with the possible exception of caffeine). And although there is some evidence that rats can become sugar-dependent under certain specific circumstances (involving having them fast), tolerance has not been “convincingly demonstrated,” and applying rodent models of addiction to humans is controversial at best.

If your concern is that you will develop a physiological dependence on sugar, you needn’t worry. That kind of addiction, like one might have to heroin, is simply not going to happen.

But there are other ways to think about addiction that could apply to sugar. The current (Fifth) edition of the Diagnostic and Statistical Manual of Psychological Disorders includes what it calls “substance use disorder,” which is its version of addiction. Even if it’s a “severe” case, to be diagnosed with that disorder you don’t need to show tolerance or withdrawal. Those are merely two among the 11 symptoms that would count toward a diagnosis. Other symptoms that more easily map onto sugar use include having a strong desire or craving to consume it, consuming more of it than you intend, having persistent unsuccessful attempts to cut down on it, and continuing to use it even though it’s causing you problems.

This means that if you eat too much sugar and have tried and failed to cut it from your diet, you would technically qualify for a mild case of substance use disorder (provided those symptoms are causing you “significant impairment or distress”). Not the scary image that comes to mind when thinking about heroin addiction. A moderate case of substance use disorder involves having four or five symptoms; six or more qualifies as severe. Even with this definition, a severe case is unlikely, because even if you had all four of the symptoms listed above, the remaining ones (and tolerance and withdrawal) are less likely to apply to sugar. Most sugar-loving people won’t have two or more of these symptoms: failure to fulfill major role obligations; interference with important activities; social problems; too much time and effort seeking it or recovering from its effects; and repeated use in situations in which it is hazardous. People with binge eating disorder may engage in some of these behaviors when binge eating, but that is an overall eating problem, not a physiological dependence on specific foods.

Sweeping statements that vilify entire food groups (or specific foods) lead to eating rules that can backfire into overeating the forbidden foods or can become unhealthy obsessions.

The skeptical reader may be thinking here about highly publicized studies (many summarized here) that show that anticipating sugary foods activates the same parts of the brain as when drug addicts are exposed to drug-related cues. Perhaps this sounds exciting, but there are important problems with this work. First, much of it was conducted on rats, not people (reviewed here), and the researchers point out that the effects with sugar are smaller than those with drugs. What’s compelling was the idea that consuming sugar gives just as powerful a response as using heroin, and is therefore just as dangerous and addicting. Not even the rat studies suggest that to be the case. Second, when all of the studies on this topic are examined, it is evident that the results are highly inconsistent and frequently don’t show these patterns. In fact, the author of the most thorough review of this work concluded, rather vehemently, that the functional neuroimaging studies did not support the idea of food addictions.

Finally, it’s not clear what it would mean even if the patterns were consistent. Other than addictive drugs, there are many different experiences that stimulate these same brain regions, including winning and anticipating winning money and even listening to highly pleasurable music. Just because sugar (or other highly palatable foods) also stimulates these circuits does not mean that sugar is addictive. It’s a classic logic error, akin to saying that since having anthrax causes a fever, having a fever means you have anthrax. Although this pattern of results—if we found it consistently—would be necessary if sugar were truly addictive, it is not sufficient to prove that sugar is addictive.

So why do I care? As a health psychologist, I often see people choose unnecessary and unpleasant diets based on unsubstantiated claims. Sweeping statements that vilify entire food groups (or specific foods) lead to eating rules that can backfire into overeating the forbidden foods or can become unhealthy obsessions, occupying valuable mental space and leading to self-shaming and other miseries.

There’s nothing wrong with including sugar in your sensible ‘everything in moderation’ eating plan. But I’d avoid the heroin.