In my continuing effort to debunk or support nutritional claims, I will focus today on whether sugar is addictive. You cannot spend more than five minutes in a comment section on nutrition before someone says “Sugar is as addictive as cocaine.”
And again, I believe a lot of simply accept that as a fact, even among reasonably scientific people. My default position regarding any nutritional claim these days is that there’s a 95% chance that it’s bogus.
There are a lot of nonsensical claims about sugar, and I’ll get to them during the next few weeks, but again, we are going to target the claim that sugar is addictive. And we’ll use real science, which is missing from almost every nutritional claim.
What is this claim that sugar is addictive?
A lot of people have been claiming that sugar is addictive. I even found such claims on websites that focus on drug addictions. Here’s one from The Addiction Center:
Some studies have suggested that sugar is as addictive as Cocaine. People often enjoy the dopamine release that sugar brings. But due to the addictive nature of sugar, long-term health effects like obesity and diabetes are a risk of sugar overindulgence. Similar to other compulsions or behavioral addictions, sugar addiction is a special risk for people with low moods, anxiety, and stress.
Of course, they don’t link to a study that supports these claims, but I’ll get to them in a bit.
Another website, Healthline, makes the same claim. They state that “experts agree” that sugar is as addictive as cocaine. What experts? Where is this published? Once again, it’s hard to tell.
This is getting like my article looking into the effects of artificial sweeteners on health — without making the effort to examine the science, so-called health experts accepted false claims as fact. It is frustrating.
The top Google hits for “sugar addiction” lead to a list of authoritative websites that all seem to reiterate the same claim — sugar is as addictive as cocaine. This is why most of us who rest our laurels on the foundation of scientific skepticism never take Google hits as being authoritative.
We need to dig into these claims and find out what the best research says.
Time for some science
A lot of these claims about sugar seem to come from a set of experiments with rats where they were given a choice between cocaine and sugar water, and they always chose sugar water.
Across species, drugs like cocaine are thought to have rewarding effects that greatly surpass those of other, nondrug rewards. So, shouldn’t most rats choose cocaine? Yet, most rats choose the other, nondrug reward instead. This is true for both sexes, and even for rats with rather extensive drug using histories.
So based on these rat studies, it must be true that humans would prefer sugar to cocaine, making it more addictive than cocaine. Except, that’s not the conclusion I would make.
I’ve written about this extensively that animal studies rarely (less than 1% of the time) lead to clinical significance. That’s why most drug studies are failures even if they show promise in rats or cultured cells.
Most importantly, the design of these experiments was incorrect. There is a delay in a positive response to cocaine compared to sugar water, which is almost immediate. But once the delays are accounted for, delaying the availability of the sugar water for several minutes, the rats preferred the cocaine.
Furthermore, the rats preferred other rewards, such as regular rat food, over cocaine. But once there was a delay in receiving the alternative rewards (like sugar water), they went after the cocaine.
If sweetened water is more rewarding than cocaine (a pharmacodynamic account), then the rats should continue to choose the sweetened water over the drug, regardless of the programmed delay. These findings suggest that, in choice studies, rats normally choose the alternative reward over cocaine likely because the delay to cocaine reward is longer.
Now these studies don’t directly debunk the “sugar is addictive as cocaine” narrative, but they show that cocaine is more addictive than sugar when rats are given a choice that accounts for the slight time delay in the cocaine’s effect over alternatives, such as sugar water.
More science
One of the criticisms of the rat studies is that there might be a simpler conclusion for why rats preferred sugar water over cocaine (at least when they were offered at the same time) — palatability. Simply put, the sugar water tasted better.
So how do we apply this to humans? A review of sugar addiction research by David Benton, Ph.D., of the Department of Psychology, University of Swansea, Wales, believes that the hypothesis that sugar is addictive is implausible.
First, Benton states that humans would rarely choose pure sucrose or fats alone. If sugar was truly addictive, then packets of sugar would be the food of choice for those “addicted” to sugar. Humans choose foods for a lot of reasons — taste, texture, sweetness, umami, etc.
One person may want their sugar in the form of chocolate ice cream, but that might be disgusting to another. One person might like coffee very sweet while another would find it revolting. This is why we cannot and should not apply animal models for nutrition to humans — human decision-making is substantially more complicated than a rat trying to choose between cocaine and sugar water.
As Dr. Benton writes, “The day-to-day food preference of rats reflects palatability rather than sucrose content.” In other words, these rat studies that appear to be the basis of every single claim that sugar is as addictive as cocaine cannot be applied to human behavior towards food, specifically sugar.
Dr. Benton concludes:
There is no support from the human literature for the hypothesis that sucrose may be physically addictive or that addiction to sugar plays a role in eating disorders.
Here’s what I found — every single primary research paper that was listed in a PubMed search of “sugar addictive cocaine” referred to animal studies. As Dr. Benton wrote, none showed the effect in humans. None.
There were a lot of “opinion” papers that were published, many in respected journals, that made wild claims about sugar addiction, but they did not present any clinical trial, cohort, or case-control studies that supported these claims. What’s telling is that this claim about sugar being as addictive as cocaine narrative is old, so in the past decades, why hasn’t there been one human study that supported this claim?
Even more science
I had to do some digging, but I found a human cross-sectional study published in Appetite in July 2017. The researchers studied 1495 university students who were assessed for DSM-related signs of food addiction for particular food categories. The researchers concluded that:
The current findings indicate that sugary foods contribute minimally to ‘food dependence’ and increased risk of weight gain. Instead, they are consistent with the current scientific notion that food energy density, and the unique individual experience of eating, plays an important role in determining the reward value of food and promoting excessive energy intake.
Summary
Sometimes the absence of evidence is evidence of absence, especially when there have been several years of looking for that evidence. Right now, we know that rats, under very specific conditions, might appear to show an addiction to sugar. But, it may be more about palatability over cocaine rather than sugar itself.
Furthermore, there appears to be a total lack of biological plausibility, a critical step in showing causation between sugar and some level of addiction.
And the limited human studies that attempted to show a link between sugar and some type of psychological or physiological dependence were negative.
Right now, based on the lack of clinical or epidemiological evidence, it appears that the claim that sugar is as addictive as cocaine is utterly bogus. This is frustrating to me, because so many ostensibly reliable sources keep making this claim, yet it’s based on nothing.
Maybe someone will publish a cornerstone article that shows humans can be addicted to sugar, but until that time, I will stand by my conclusion — it’s bogus.
Citations
- Benton D. The plausibility of sugar addiction and its role in obesity and eating disorders. Clin Nutr. 2010 Jun;29(3):288-303. doi: 10.1016/j.clnu.2009.12.001. Epub 2009 Dec 28. PMID: 20056521.
- Markus CR, Rogers PJ, Brouns F, Schepers R. Eating dependence and weight gain; no human evidence for a ‘sugar-addiction’ model of overweight. Appetite. 2017 Jul 1;114:64-72. doi: 10.1016/j.appet.2017.03.024. Epub 2017 Mar 19. PMID: 28330706.
- Samaha AN. Sugar now or cocaine later? Neuropsychopharmacology. 2021 Jan;46(2):271-272. doi: 10.1038/s41386-020-00836-z. Epub 2020 Sep 1. PMID: 32873901; PMCID: PMC7852671.
